New approaches to kidney banking through nature-inspired high sub-zeropreservation strategies

ABSTRACTThe broad aim of this program targets the banking of kidneys for transplantationWe propose to develop a nature inspiredholistic and non toxic solution to dramatically extend preservation times during transplantation of human and xeno kidneysOur approach is based on the best strategies employed by freezetolerant and hibernating animals in nature augmented with complementary strategies developed using recent scientific understanding and bioengineering principlesImportantlyour approach does not seek to solve all the problems needed for vitrification or classical cryopreservationbut rather be the first to develop organ preservation in a controlledpartially frozen or ice free equilibrium state using high subzero temperaturesranging fromtoCcombined with metabolic depressionThese are temperatures and strategies used in nature by species able to survive months in a state ofsuspended animationwith the whole animalincluding every single organ beingbankedwithout injuryWe have conceived an integrated approach in which we will develop a new stasis cocktail optimized for the critical phases of protectionprior to storagepreservationduring storageand revival resuscitationafter storageA critical aspect for translation of this technology to complex organs will be designing and optimizing a stasis cocktail which will serve the heterogeneous cell types of the kidney together with well developed model systems for renal transplantAcross three specific aimsin this first phasewe use representative renal cell typesHuman Renal Proximal Tubular Epithelial CellsHRPTEpiCand Human Renal Glomerular Endothelial CellsHRGECas a simplified in vitro kidney modelThe objective is to develop anature inspiredbioengineering augmented non toxic cryostasis cocktail that seeks to accomplish a broader set of goals than traditional cryoprotectants andpre conditioningcoolingand rewarming protocol for high subzero cryopreservation in the presence of limitedcontrolled ice or total absence of ice in a thermodynamically stable stateSpecificallythe study is designed to contrast the efficacy of a partial freezing strategy with an ice free approachboth of which are employed in natureWe will combine components that enablearesistance to deleterious changes in cell volume and prevention of intracellular ice formation through the use of low molecular weight compoundsbthe active suppression of metabolic rate beyond what is possible through passive temperature effects alonethrough the application of metabolic rate inhibitorsandcthe enhancement of stress tolerance and reduction of cryoinjury through the application of antioxidants and prosurvival compoundsThe best conditions will then be evaluated using a whole kidney model in Phase Iand ultimately kidney transplant in Phase IIThis specific proposal is an important standalone project that also should lead to solutions for preservation of natural and engineered vital organsas well as for traditional cell and tissue bankingUltimatelywe anticipate achieving up todays banking using the best of these approaches which would be a game changer for transplantation and allow time for induction of immune tolerance in the recipient Narrative The need for organ transplantation is continuing to grow steadily and official U Sorgan transplant waitlist statistics show that there areX the number of people on the waitlist than received a transplant last yearUnited Network of Organ SharingUNOSdataand other estimates suggest thatof all annual U Sdeaths would be prevented by organ transplantationAt the same timemany vital organs are left unused due to the short amount of time that organs can be kept alive for transport and of those used the risk of ischemic and other forms of damage still exists and can contribute to graft rejectionShort preservation times and risk of ischemia also constrain optimal donor recipient matching and prevent the ultimate strategy of immune tolerance inductionOur technology promises to overcome these issues by markedly extending the preservation time enabling tissue matched organs stored for sufficient timeweeks to monthsto meet the challenges of global transportation and immune tolerance induction