The review, led by Marissa C. Kuo and W. Christian Crannell of Vanderbilt University Medical Center with colleagues across Vanderbilt’s surgical, nephrology, biomedical engineering, and cardiac surgery departments, synthesized preclinical and clinical evidence on 10 degrees Celsius static storage in heart, lung, liver, and kidney transplantation. Guided by the Preferred Reporting Items for Systematic Reviews and Meta-Analysis scoping review guidelines, the team searched PubMed, Embase, Web of Science, and Scopus on May 22, 2025, returning 1,182 articles. After duplicate removal and independent screening by two reviewers, 45 studies met inclusion criteria, supplemented by 8 studies retrieved from reference lists and 15 additional references covering perfusion strategies, mitochondrial biomarkers, and controlled rewarming. The result is the most complete picture to date of a preservation approach that is quietly reshaping transplant practice.

The strongest evidence comes from lung transplantation. In animal models, storage at 10 degrees Celsius compared with conventional ice has been associated with improved oxygen uptake, lower airway pressures, greater lung compliance, less edema, better arterial oxygenation, and lower pulmonary vascular resistance after transplantation. Biochemical markers of inflammation, including interleukin-8 and interleukin-1 beta, were lower after reperfusion in organs kept at the warmer temperature. Metabolomic studies add mechanistic depth: in a porcine model, lungs stored at 10 degrees Celsius showed upregulation of protective metabolites such as glutathione and ascorbate, downregulation of substrates that induce mitochondrial depolarization, and elevated mitochondrial respiration supported primarily by complexes I and II. Lipid byproducts dominated the metabolite profile, suggesting that beta-oxidation may serve as an alternative energy substrate that keeps graft metabolism gently active, an organ-protective state the authors liken to hibernation.

Clinical experience in lungs has moved rapidly from proof of concept to multicenter trials. A 2021 pilot study of five bilateral lung transplants using 10 degrees Celsius storage reported zero cases of grade 3 primary graft dysfunction, no need for postoperative extracorporeal membrane oxygenation, and 100 percent 30-day survival. A retrospective matched cohort study found that preservation times extending up to 24 hours at 10 degrees Celsius produced no differences in mechanical ventilation time, intensive care or hospital stay, primary graft dysfunction rates, or survival compared with ice storage. A single-institution prospective study and the largest trial to date, a multicenter non-randomized prospective study of 70 donor lungs stored at 10 degrees Celsius overnight and transplanted the next morning, both found outcomes equivalent to conventional storage, with the multicenter trial reporting primary graft dysfunction rates of 5.7 percent versus 9.3 percent in controls. An international randomized non-inferiority trial has recently completed enrollment and may settle the question definitively.

The clinical implications extend beyond graft function into the logistics of transplantation itself. Because organs stored at 10 degrees Celsius tolerate longer cold ischemic times, surgical teams can schedule transplants during daytime hours rather than performing emergency operations in the middle of the night. Case reports describe hearts transported more than 10 hours without machine perfusion, from Anchorage, Alaska to Nashville, Tennessee, and sequential transplantation of two lungs from a single donor into two different recipients at different institutions. For a field in which more than 23,000 waitlisted patients died awaiting a kidney transplant in the United States between 2020 and 2024, and nearly 31,000 died waiting for any organ, every hour of safe preservation time translates into more organs reaching more patients.

Heart transplantation data, though earlier in its development, are similarly encouraging. A propensity-matched cohort study using a reusable 10 degrees Celsius cooler for organ transport found lower lactate changes and slightly higher cardiac index at 24 and 72 hours postoperatively compared with ice storage, though primary graft dysfunction rates did not differ and donor characteristics were not perfectly balanced. A more recent study of hearts procured after thoracoabdominal normothermic regional perfusion found that 10 degrees Celsius storage was associated with reduced risk of primary graft dysfunction, lower postoperative vasoactive inotropic scores, decreased use of renal replacement therapy, shorter intensive care stays, and reduced six-month mortality. Animal work dating back decades supports the temperature window: canine and rat studies found mitochondrial structural changes were less severe below 14 degrees Celsius, and that high-energy phosphate content was severely depleted only when storage temperatures exceeded 10 degrees Celsius.

The biochemical rationale centers on the mitochondria. At deep hypothermic temperatures near 4 degrees Celsius, the oxygen-binding equilibrium of myoglobin strongly favors the oxygenated form, but cytosolic oxygen diffusion slows dramatically and mitochondrial respiration becomes markedly attenuated. In this near-static state, the mitochondrial proton-motive force collapses, forcing ATP synthase to run in reverse and hydrolyze ATP, while electron flow reverses through succinate dehydrogenase, causing succinate to accumulate, a metabolic hallmark of ischemia. Upon reperfusion, rapid oxidation of that succinate generates a burst of superoxide radicals that can trigger mitochondrial permeability transition pore opening, cytochrome c release, and apoptotic signaling. Released mitochondrial DNA then circulates as a damage-associated molecular pattern, activating innate immune pathways that contribute to graft inflammation and rejection. Moderate cooling to around 10 degrees Celsius, by contrast, appears to preserve slow, reversible electron transport, maintain mitochondrial ultrastructure, and keep myoglobin-mitochondrial oxygen coupling intact.

Evidence in liver and kidney transplantation remains thinner and more mixed. In a comprehensive porcine model of donation after circulatory death, 10 hours of 10 degrees Celsius static storage followed by normothermic perfusion produced superior hemodynamic profiles, more bile with higher pH and bicarbonate, and metabolomic evidence of less citric acid cycle dysfunction and mitochondrial oxidative damage than ice storage, but no human liver studies have yet been published. Older kidney studies yielded conflicting results, with some suggesting slightly higher temperatures may better preserve adenine nucleotide levels, and species differences in mitochondrial temperature responses complicate extrapolation to humans. A 2024 rat cell study found the highest viability at 10 degrees Celsius, and a single human deceased donor kidney transplant after 10 degrees Celsius storage achieved immediate graft function, the first patient in a larger prospective trial now underway.

The review also situates 10 degrees Celsius storage within the broader landscape of preservation technology, including oxygenated hypothermic perfusion and controlled rewarming. Randomized trials of hypothermic oxygenated perfusion in liver transplantation have shown fewer non-anastomotic biliary strictures and less early allograft dysfunction, while a kidney trial of extended criteria donors showed no benefit, possibly because organs were stored on ice before perfusion began. Controlled oxygenated rewarming studies suggest that a gentler temperature gradient at reperfusion protects mitochondrial coupling, a benefit that 10 degrees Celsius storage could amplify by starting closer to physiological temperature. Notably, no study has directly compared static 10 degrees Celsius storage with machine perfusion, and the authors suggest that a simple, inexpensive cooler could in some cases obviate the need for costly perfusion devices.

The authors are careful about the limits of the evidence. Definitive conclusions, they write, await well-designed randomized clinical trials capable of providing the highest quality evidence, and the data are far stronger for heart and lung storage than for liver and kidney. Yet the convergence of mechanistic plausibility, decades of animal data, and increasingly positive clinical experience has given the field reason to reconsider a fundamental assumption: that colder is always better. If ongoing randomized trials confirm the early signals, the humble bag of ice that has defined organ preservation since the advent of transplantation may give way to a precisely controlled 10 degrees Celsius, a change that costs little, requires no complex machinery, and could extend the reach of every donated organ.

Subject of Research: Static organ storage at 10 degrees Celsius as an alternative to conventional ice preservation in deceased donor heart, lung, liver, and kidney transplantation

Article Title: 10° Celsius Static Storage in Deceased Donor Organ Transplantation: A Narrative Review

Article References: Kuo, M. C., Breeding, E., Kiyimba, F., Gohar, E. Y., Walden, R. L., Bacchetta, M., & Crannell, W. C. (2026). 10° Celsius Static Storage in Deceased Donor Organ Transplantation: A Narrative Review. Current Transplantation Reports, 13(1), Article 31. https://doi.org/10.1007/s40472-026-00528-5

Image Credits: AI Generated

DOI: 10.1007/s40472-026-00528-5

Keywords: organ transplantation, organ preservation, 10 degrees Celsius storage, static cold storage, mitochondria, ischemia-reperfusion injury, lung transplantation, heart transplantation, cold ischemia time, machine perfusion, deceased donor, primary graft dysfunction