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Urine recirculation during normothermic kidney preservation improves energy balance involving the urea and TCA cycles

Abstract:
Background: Deceased donor kidneys experience cellular stress before undergoing transplantation. To alleviate this, preservation techniques were developed including normothermic machine perfusion (NMP).

Methods: Here, we performed kidney NMP on discarded human kidneys for up to 24 hours. Volume management was regulated either by urine recirculation (UR) or urine replacement (NUR) with Ringers lactate. Notably, UR led to longer perfusion times compared to NUR. To investigate kidney NMP metabolic traits with or without UR over time, we performed longitudinal metabolomics analyses of perfusates of eight NMP kidneys by 2D-gas chromatography mass spectrometry (GCxGC-MS).

Results: Over 600 metabolic features were profiled, from which 74 were identified and 54 consistently quantified across 26 perfusate samples. Most notably, elevated levels of disaccharides (different isomers), hydroxy-purines, urea, glutamate and amino acids associated with the perfusion factor UR. Moreover, donor estimated glomerular filtration rate (eGFR) correlated significantly with the accumulation of lactate and gluconate. Most strikingly, lactate levels seemed to be more balanced in UR NMP perfusate, which otherwise accumulated rapidly within the first six hours.

Conclusions: Kidney preservation by NMP was previously limited to hours. UR-NMP affected kidney energy homeostasis, carbohydrate & purine metabolism and the Urea and TCA cycles. These insights add value to explain how urine-driven adaptations contribute to prolonged kidney function under NMP.
Publication status:
Published
Peer review status:
Not peer reviewed

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Preprint server copy:
10.64898/2026.01.12.698950

Authors

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Role:
Author
ORCID:
0000-0002-0582-1815
More by this author
Institution:
University of Oxford
Division:
MSD
Department:
NDM
Sub department:
Target Discovery Institute
Role:
Author
More by this author
Institution:
University of Oxford
Division:
MSD
Department:
NDM
Sub department:
Target Discovery Institute
Role:
Author
ORCID:
0000-0002-9762-843X
More by this author
Institution:
University of Oxford
Division:
MSD
Department:
Surgical Sciences
Role:
Author
ORCID:
0000-0003-3846-0101
More by this author
Institution:
University of Oxford
Division:
MSD
Department:
NDM
Sub department:
Target Discovery Institute
Role:
Author
ORCID:
0009-0008-9407-3142


More from this funder
Funder identifier:
https://ror.org/03x94j517
Funding agency for:
Ploeg, RJ
Grant:
MR/R014132/1
More from this funder
Funder identifier:
https://ror.org/042pgcv68
Funding agency for:
Kessler, BM
Grant:
2024-I2M-2-001-1


Preprint server:
bioRxiv
Publication date:
2026-01-13
DOI:


Language:
English
Keywords:
Pubs id:
2358999
UUID:
uuid_46ccc2cf-6e37-4272-862b-d487792d6e45
Local pid:
pubs:2358999
Deposit date:
2026-01-14
ARK identifier:

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