Cited by 173Organ Transplantation Techniques and OutcomesReproductive Biology and FertilityTransplantation: Methods and Outcomes

The DOI matches its Crossref record; 52 of the 52 references it cites were found in a registry or an index; 3 of the 47 sources its claims cite were checked for support.

Vitrification and nanowarming enable long-term organ cryopreservation and life-sustaining kidney transplantation in a rat model

Open access

Abstract

Banking cryopreserved organs could transform transplantation into a planned procedure that more equitably reaches patients regardless of geographical and time constraints. Previous organ cryopreservation attempts have failed primarily due to ice formation, but a promising alternative is vitrification, or the rapid cooling of organs to a stable, ice-free, glass-like state. However, rewarming of vitrified organs can similarly fail due to ice crystallization if rewarming is too slow or cracking from thermal stress if rewarming is not uniform. Here we use “nanowarming,” which employs alternating magnetic fields to heat nanoparticles within the organ vasculature, to achieve both rapid and uniform warming, after which the nanoparticles are removed by perfusion. We show that vitrified kidneys can be cryogenically stored (up to 100 days) and successfully recovered by nanowarming to allow transplantation and restore life-sustaining full renal function in nephrectomized recipients in a male rat model. Scaling this technology may one day enable organ banking for improved transplantation.

Overview

AI snapshot

Written from the paper’s full text.

TL;DR

This study reports vitrification and nanowarming of rat kidneys stored for 1–100 days at −150 °C, followed by transplantation into nephrectomized male rats. Nanowarmed kidneys restored life-sustaining renal function, and all recipients survived the 30-day endpoint, with function normalizing after 2–3 weeks.

Key findings

  • Vitrified kidneys were stored for 1–100 days at −150 °C and rewarmed by nanowarming at 72.0 ± 8.0 °C/min, faster than the ~50 °C/min critical warming rate of VMP in kidney tissue; cooling was 20.5 ± 8.1 °C/min versus a 2 °C/min critical cooling rate.
  • In syngeneic Lewis-to-Lewis transplants with both native kidneys removed, all fresh control and nanowarmed kidney recipients survived the full 30-day study; serum creatinine in nanowarmed recipients peaked on days 2–3, fell below 2.0 mg/dL by day 19, reached normal rat range by day 23 (0.4–0.8 mg/dL), and from day 14 onward was not statistically different from controls.
  • At 30 days, eGFR was 2.2 ± 0.8 mL/min in nanowarmed recipients versus 2.7 ± 0.7 mL/min in controls (P = 0.421), and serum/urine parameters were statistically similar and essentially normal; no correlation was found between preservation time and peak creatinine, time to creatinine <2.0, or terminal creatinine (all P > 0.5).
  • During normothermic machine perfusion, nanowarmed kidneys made urine immediately and had vascular resistance of 31.3 ± 3.6 mmHg/mL/min × g, not statistically different from fresh control (18.8 ± 4.1, P = 0.9), 24-h cold stored (24.9 ± 2.6, P = 1.0), or VMP-only (27.5 ± 3.4, P = 1.0), but much lower than VS55-only (372 ± 131, P < 0.001).

Methods

  • Male Lewis and Sprague Dawley rats (450–525 g) were used; kidneys were recovered, flushed with UW solution, perfused with VMP CPA plus silica/PEG-coated iron oxide nanoparticles, cooled in a controlled-rate freezer to −150 °C, stored for 1–100 days, and rewarmed in a 15 kW RF coil at 63 kA/m and 180 kHz.
  • Assessments included micro-CT, histology, differential scanning calorimetry, normothermic machine perfusion with oxygenated acellular Krebs–Henseleit buffer, and syngeneic Lewis-to-Lewis kidney transplantation with bilateral native nephrectomy and daily laboratory follow-up to 30 days; limited allogeneic transplants and a 60-h cold-stored comparison were also performed.
  • Statistical analysis used R version 4.2.1 with ANOVA/Tukey HSD or Games–Howell, Wilcoxon/Kruskal–Wallis, and Pearson’s Chi-squared tests; biological replicates were n = 4–8 per group.

Limitations

  • Stated by the paper: the study was performed in a rat model with limited sample size (n = 4–8 per group), not human or human-sized porcine kidneys; storage was studied only up to 100 days; transplant recipients were followed only to 30 days; only a limited number of allogeneic transplants were performed and host immune response was not characterized; mechanisms of initial transplant dysfunction were not determined; comparison to other transplant categories such as 36–48 h cold storage was incomplete; and nanowarmed organs experienced 2–3 weeks of initial graft dysfunction.
  • Evident from the text: all transplant experiments used male rats only, and no long-term survival or chronic allograft outcomes beyond 30 days were assessed.

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Integrity signals

Registry

Crossref · 10.1038/s41467-023-38824-8

Cites

52 of 52 references verified0 citation errors · 0 not checkable

Statistics

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Figures

Fig. 1 Overview of nanowarming. Depicted are the sequential steps of the nanowarming procedure as follows: (1) Kidney recovery from the donor; (2) Loading of cryoprotective agents (CPAs) and iron oxide nanoparticles (IONPs); (3) Rapid cooling to a vitrified state; (4) Storage at −150 °C until needed; (5) Rapid and uniform rewarming in radiofrequency (RF) alternating electromagnetic field; (6) Unloading of CPA and IONPs; and finally, organs are ready for (7A) assessment by normothermic machine perfusion or (7B) transplantation.
Fig. 1 Overview of nanowarming. Depicted are the sequential steps of the nanowarming procedure as follows: (1) Kidney recovery from the donor; (2) Loading of cryoprotective agents (CPAs) and iron oxide nanoparticles (IONPs); (3) Rapid cooling to a vitrified state; (4) Storage at −150 °C until needed; (5) Rapid and uniform rewarming in radiofrequency (RF) alternating electromagnetic field; (6) Unloading of CPA and IONPs; and finally, organs are ready for (7A) assessment by normothermic machine perfusion or (7B) transplantation.CC BY · PubMed Central
Fig. 2 Vitrification and nanowarming of kidneys. a CPA concentration, perfusion pressure, arterial flow rate, and temperature profile during the loading and subsequent unloading of CPA and IONPs in rat kidneys. b Representative thermal profile during cooling from above the melting temperature (Tm = −40.8 °C) to an annealing step just above the glass transition temperature (Tg = −128.3 °C), and finally slower cooling into the glassy zone. The blue shaded area is the zone of risk for ice formation. Inset are cooling rates and the critical cooling rate (blue dashed line, CCR = 2 °C). n = 8. c Representative thermal history during nanowarming, rewarming rates, and the critical warming rate (red dashed line, CWR = 50 °C). n = 8. Representative photograph (d) and pseudocolor image acquired by micro-CT (e) of the vitrified VMP-loaded kidney. Representative photo (f) and pseudocolor image acquired by micro-CT (g) of the vitrified VMP + IONP-loaded kidney. The pseudocolor scale shows micro-CT image radiodensity (in Hounsfield units). Data are mean ± s.d. Source data are provided as a Source Data file. HU Hounsfield units; Tg glass transition temperature; Tm, melting temperature.
Fig. 2 Vitrification and nanowarming of kidneys. a CPA concentration, perfusion pressure, arterial flow rate, and temperature profile during the loading and subsequent unloading of CPA and IONPs in rat kidneys. b Representative thermal profile during cooling from above the melting temperature (Tm = −40.8 °C) to an annealing step just above the glass transition temperature (Tg = −128.3 °C), and finally slower cooling into the glassy zone. The blue shaded area is the zone of risk for ice formation. Inset are cooling rates and the critical cooling rate (blue dashed line, CCR = 2 °C). n = 8. c Representative thermal history during nanowarming, rewarming rates, and the critical warming rate (red dashed line, CWR = 50 °C). n = 8. Representative photograph (d) and pseudocolor image acquired by micro-CT (e) of the vitrified VMP-loaded kidney. Representative photo (f) and pseudocolor image acquired by micro-CT (g) of the vitrified VMP + IONP-loaded kidney. The pseudocolor scale shows micro-CT image radiodensity (in Hounsfield units). Data are mean ± s.d. Source data are provided as a Source Data file. HU Hounsfield units; Tg glass transition temperature; Tm, melting temperature.CC BY · PubMed Central
Fig. 3 Histologic appearance of CPA-only treated and CPA plus nanowarmed kidneys. Histological changes (H&E) of renal cortex and medulla following treatment with CPA (VS55-only and VMP-only) and vitrification and nanowarming (N–W) compared to fresh untreated controls. Scale bars are 100 µm. Data are representative images from n = 6 (Fresh Control and Nanowarmed), n = 3 (VS55), and n = 4 (VMP) separate experiments for each condition. H&E, hematoxylin and eosin.
Fig. 3 Histologic appearance of CPA-only treated and CPA plus nanowarmed kidneys. Histological changes (H&E) of renal cortex and medulla following treatment with CPA (VS55-only and VMP-only) and vitrification and nanowarming (N–W) compared to fresh untreated controls. Scale bars are 100 µm. Data are representative images from n = 6 (Fresh Control and Nanowarmed), n = 3 (VS55), and n = 4 (VMP) separate experiments for each condition. H&E, hematoxylin and eosin.CC BY · PubMed Central
Fig. 4 Normothermic machine perfusion of rat kidneys using acellular blood substitute. a Schematic of the normothermic perfusion system for diagnostic assessment of fresh untreated (control), 24-h UW preserved (24 h), VMP loaded-unloaded (VMP), VS55 loaded-unloaded (VS55), and vitrified and nanowarmed (V–N) rat kidneys. b Cumulative urine output over the course of perfusion. c Creatinine clearance. d Alterations in renal artery flow. e Oxygen consumption rate. f Venous pH. g Vascular resistance. h Lactate production. i Glucose consumption. Data are mean ± s.d. n = 4 per condition. Statistical comparison between nanowarmed kidney and other treatment groups at minute 40 using ANOVA and Tukey HSD (Games–Howell if unequal variance) post hoc tests. *P < 0.05, **P < 0.01, ***P < 0.001; NS, not significant. Full statistical treatment in Supplementary materials. Source data are provided as a Source Data file. OCR oxygen consumption rate; V–N, vitrified and nanowarmed.
Fig. 4 Normothermic machine perfusion of rat kidneys using acellular blood substitute. a Schematic of the normothermic perfusion system for diagnostic assessment of fresh untreated (control), 24-h UW preserved (24 h), VMP loaded-unloaded (VMP), VS55 loaded-unloaded (VS55), and vitrified and nanowarmed (V–N) rat kidneys. b Cumulative urine output over the course of perfusion. c Creatinine clearance. d Alterations in renal artery flow. e Oxygen consumption rate. f Venous pH. g Vascular resistance. h Lactate production. i Glucose consumption. Data are mean ± s.d. n = 4 per condition. Statistical comparison between nanowarmed kidney and other treatment groups at minute 40 using ANOVA and Tukey HSD (Games–Howell if unequal variance) post hoc tests. *P < 0.05, **P < 0.01, ***P < 0.001; NS, not significant. Full statistical treatment in Supplementary materials. Source data are provided as a Source Data file. OCR oxygen consumption rate; V–N, vitrified and nanowarmed.CC BY · PubMed Central
Fig. 5 Electrolytes and glucose during normothermic perfusion of kidneys. a–d Venous effluent (left) and e–h Urine (right) effluent analysis of electrolytes and glucose during 40 min of normothermic machine perfusion of fresh control, 24-h cold stored, VMP-only, and VS55-only treated kidneys were compared to nanowarmed kidneys. Measured parameters include sodium (a, e), potassium (b, f), chloride (c, g), and glucose (d, h). Data are mean ± s.d. for n = 4 for each group and time point. Source data are provided as a Source Data file. V–N, vitrified and nanowarmed.
Fig. 5 Electrolytes and glucose during normothermic perfusion of kidneys. a–d Venous effluent (left) and e–h Urine (right) effluent analysis of electrolytes and glucose during 40 min of normothermic machine perfusion of fresh control, 24-h cold stored, VMP-only, and VS55-only treated kidneys were compared to nanowarmed kidneys. Measured parameters include sodium (a, e), potassium (b, f), chloride (c, g), and glucose (d, h). Data are mean ± s.d. for n = 4 for each group and time point. Source data are provided as a Source Data file. V–N, vitrified and nanowarmed.CC BY · PubMed Central
Fig. 6 Gross and histologic appearance of nanowarmed and control kidney transplants. Representative appearance of fresh control kidney before cannulation and recovery (n = 5), 60-h cold-stored kidney at the time of intraoperative transplant organ failure (n = 1), fresh control kidney transplants at day 30 post transplant (n = 5), nanowarmed kidney transplants at day 30 post transplant (n = 5). a Gross images in situ. b Bisected kidneys following explant. c Histology of renal cortex (H&E). d Histology of renal medulla (H&E). Scale bars are 100 µm. H&E hematoxylin and eosin.
Fig. 6 Gross and histologic appearance of nanowarmed and control kidney transplants. Representative appearance of fresh control kidney before cannulation and recovery (n = 5), 60-h cold-stored kidney at the time of intraoperative transplant organ failure (n = 1), fresh control kidney transplants at day 30 post transplant (n = 5), nanowarmed kidney transplants at day 30 post transplant (n = 5). a Gross images in situ. b Bisected kidneys following explant. c Histology of renal cortex (H&E). d Histology of renal medulla (H&E). Scale bars are 100 µm. H&E hematoxylin and eosin.CC BY · PubMed Central
Fig. 7 Transplant outcomes of nanowarmed and fresh control kidney transplants. a Depiction showing the transplant schema. Organs were recovered from donor rats and either immediately transplanted (n = 5); vitrified, nanowarmed and transplanted (n = 5); or stored for 60 h (n = 1) in UW solution prior to transplant. The 60-h cold stored kidney failed intraoperatively, and the recipient was sacrificed. Nanowarmed (blue) and fresh control kidney transplants (red) were followed for 30 days post syngeneic transplant with daily labs and assessments. b Serum creatinine with individual recipient curves and aggregate data shown; c Venous potassium; d Venous pH; e Venous bicarbonate (HCO3-); f Venous partial pressure of CO2 (pCO2); g Venous lactate; h Hemoglobin. i Daily weight normalized to day −1 pretransplant. The gray bands are normal ranges. Data are mean ± s.d. Statistical tests were Wilcoxon (b, d, e, f, g, i) or t-test (c, h). *P < 0.05, **P < 0.01, ***P < 0.001; NS not significant. Source data are provided as a Source Data file. Full statistical treatment in Supplementary materials.
Fig. 7 Transplant outcomes of nanowarmed and fresh control kidney transplants. a Depiction showing the transplant schema. Organs were recovered from donor rats and either immediately transplanted (n = 5); vitrified, nanowarmed and transplanted (n = 5); or stored for 60 h (n = 1) in UW solution prior to transplant. The 60-h cold stored kidney failed intraoperatively, and the recipient was sacrificed. Nanowarmed (blue) and fresh control kidney transplants (red) were followed for 30 days post syngeneic transplant with daily labs and assessments. b Serum creatinine with individual recipient curves and aggregate data shown; c Venous potassium; d Venous pH; e Venous bicarbonate (HCO3-); f Venous partial pressure of CO2 (pCO2); g Venous lactate; h Hemoglobin. i Daily weight normalized to day −1 pretransplant. The gray bands are normal ranges. Data are mean ± s.d. Statistical tests were Wilcoxon (b, d, e, f, g, i) or t-test (c, h). *P < 0.05, **P < 0.01, ***P < 0.001; NS not significant. Source data are provided as a Source Data file. Full statistical treatment in Supplementary materials.CC BY · PubMed Central

Verification

Claims the paper makes

42 Own result · 18 Own interpretation · 13 Not checked yet · 12 Own method · 8 No full text of the sources · 5 No basis given · 1 Supported so far · 1 Partly supported · 1 Sources not found · accuracy not yet measured

Verify all 19 references — free account

Show all 35 claims

  • Probably not a substantial claim. 27
  • It may state two separate claims as one. 54
66 of 66
  • The paper relies on this without support.

    Organ banking via cryopreservation would make organ transplantation elective and improve donor/recipient matching, equity in access, patient preparation, tolerance protocols, organ utilization, and graft and patient survival.

    “Organ banking via cryopreservation would make organ transplantation an elective rather than an urgent/emergent procedure and revolutionize how organs are used to treat human disease. Better donor/recipient matching, improved equity in access, better patient preparation, better transplant tolerance protocols, increased organ utilization, and enhanced graft and patient survival could all be enabled”
  • The paper relies on this without support.

    Vitrification followed by long-term transplant success with a kidney or any organ has never been reproducibly achieved.

    “Indeed, vitrification followed by long-term transplant success with a kidney (or any organ) has never been reproducibly achieved.”
  • The paper relies on this without support.

    Perfusion within capillaries allows sufficiently uniform delivery of CPAs and IONPs regardless of organ size.

    “In addition, perfusion within the capillaries allows sufficiently uniform delivery of CPAs and IONPs regardless of organ size.”
  • The authors state this as an assumption.

    The transport from the capillary vasculature into the extravascular space occurs across a membrane (composite basement and cell membrane) that can be described by coupled solute/solvent flow using irreversible thermodynamics as described by the Kedem-Katchalsky equations.

    “The transport from the capillary vasculature into the extravascular space is assumed to occur across a membrane (composite basement and cell membrane) that can be described by coupled solute/solvent flow using irreversible thermodynamics as described by the Kedem-Katchalsky (KK) equations.”
  • The authors state this as an assumption.

    The kidney can be represented by many parallel identical cylindrical/hexagonal prism units, each consisting of a central capillary surrounded by tissue.

    “In the Krogh model, the kidney is represented by many parallel identical cylindrical/hexagonal prism units, each consisting of a central capillary surrounded by tissue.”
  • The authors state this as an assumption.

    The processes in one Krogh unit are typical and representative of the processes in the whole organ.

    “The mass transfer in the whole kidney is analyzed by considering the processes in such a unit to be typical and representative of the processes in the whole organ.”
  • The paper relies on this without support.

    Nanowarming is independent of size.

    “In contrast, nanowarming is independent of size.”
  • The paper relies on this without support.

    Fahy and colleagues have never reproduced their finding of a successful rabbit kidney transplant.

    “but have never reproduced that finding.”
  • The paper relies on this without support.

    The current organ transplantation system is based on severe time constraints from organ acquisition to transplant, typically measured in hours.

    “The current system is based on severe time constraints from organ acquisition to transplant, typically measured in hours.”
9 of 9

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Citations

Cites

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Research works printed but not linked: 1

  1. National Research Council. Realizing the Promise of Equity in the Organ Transplantation System (The National Academies Press, Washington, DC, 2022).

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Metadata

Authors
Han, Z., Rao, J. S., Gangwar, L., Namsrai, B.-E., Pasek-Allen, J. L., Etheridge, M. L., Wolf, S. M., Pruett, T. L., Bischof, J. C., & Finger, E. B.
Affiliations
University of Minnesota (US)
Corresponding author
  • Bischof, John C.
  • Finger, Erik B.
Venue
Nature Communications
Published
2023-06-09
Volume
14
Issue
1
Pages
3407-3407
ISSN
2041-1723 (ISSN-L)
OpenAlex
W4380090567
Cited by
173
References
51
Citations by year
2026: 58 · 2025: 53 · 2024: 46 · 2023: 16
FWCI
38.87
Type
journal article
Language
en
Open access
Locations
  • Nature Communications (publishedVersion, cc-by)
  • PubMed Central (publishedVersion, cc-by)
  • PubMed (publishedVersion)
  • RePEc: Research Papers in Economics (submittedVersion)
  • DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion, cc-by-sa)
Funders
  • U.S. Department of Health & Human Services | NIH | National Institute of Diabetes and Digestive and Kidney Diseases (DK117425, DK131209, DK132211)
  • Biostasis Research Institute
  • U.S. Department of Health & Human Services | NIH | National Heart, Lung, and Blood Institute (HL135046)
  • National Science Foundation (EEC-1941543)
Topics
  • Health Sciences › Medicine › Surgery › Organ Transplantation Techniques and Outcomes
  • Health Sciences › Medicine › Reproductive Medicine › Reproductive Biology and Fertility
  • Health Sciences › Medicine › Surgery › Transplantation: Methods and Outcomes
Keywords
organ cryopreservation, vitrification, nanowarming, kidney transplantation, organ banking, alternating magnetic field heating, magnetic nanoparticles, ice crystal formation, thermal stress, renal function recovery, rat model
MeSH terms
Animals, Kidney, Male, Organ Preservation, Cryopreservation, Kidney Transplantation, Rats, Vitrification

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