New approaches to kidney banking through nature-inspired high sub-zero preservation strategies - ABSTRACT
The kidney transplant waitlist comprises 83% of the U.S. organ transplant waitlist. Yet, for every 5 patients who die
or become too sick for transplantation, 3 kidneys are discarded. Organ preservation quality is linked to graft lifespan
with kidneys having only 50% graft survival after 10 years. Extending preservation to a week, or longer, would enable
nationwide (theoretically global) donor-recipient matching, allowing many good quality kidneys not transplanted today
(e.g., extended criteria donor kidneys) to be offered to the patients who most need them. Kidney preservation times
of 7-9 days would enable translation of clinical immune tolerance induction, and avoidance of life-long
immunosuppression requirements, from contexts of living donor transplantation to deceased organ donation
(80% of all transplants), improving the lives of transplant recipients, and saving the healthcare system ~ $100 million
dollars each year. Improved and extended preservation technology, with off-the-shelf availability, can enhance
screening for transmissible diseases/malignancies, allow assessment of organ quality, drug/gene therapies for graft
function augmenting, and support xeno-transplantation research. Moreover, 3D slices from preserved kidneys
unmatched for transplant, have wide applicability in drug safety/efficacy testing, and a large variety of research topics.
Building on the project's Phase I feasibility success that demonstrated unprecedented (rabbit) kidney
preservation for up to 14 days, we here scale-up this new technology to develop a (i) nature-inspired and
(ii) machine perfusion enabled, subzero solution to dramatically extend preservation times of human and
porcine (xeno) kidneys. High subzero temperatures (-12 to -20°C) applied using an ultra-stable equilibrium
approach are combined with stress tolerance enhancement and metabolic suppression strategies. Optimized
machine perfusion protocols, 3D combinatorial high throughput screening with precision cut kidney slices,
advanced µCT imaging, whole human kidney, and porcine survival auto transplantation models are employed.
Based upon the significant Phase I achievements and our team's organ preservation experience, we develop
technologies and strategies in Phase II for enhanced human kidney equilibrium ice-free high subzero banking
via: 1) multi-temperature multi-step machine perfusion platform supportive of pre-conditioning protocols, for clinical
scale kidney effective and uniform permeation, at all renal compartmental levels, with (i) biocompatible cryostasis
cocktails formulated on the basis of toxicity neutralization and mutual dilution principles, and (ii) effective
revival/reconditioning protocols for enhanced reperfusion; 2) validation of (168-216h) 7-9 days preservation in
complete absence of ice with (iii) cross country shipping of stored kidneys, and clinical practices of ex vivo renal
perfusion; 3) porcine model kidney orthotopic transplantation with long-term survival, with and without “anywhere
in the world” shipping, and 4) randomized physiologic ex vivo assessment trial of 7-9 days stored human kidneys.
This Phase II sets the stage for logistical model of centralized centers of excellence for preservation and
assessment, enabling vastly improved clinical outcomes and patients' access across the country, and world.
