Prevention of Chronic Rejection of Marginal Kidney Graft by Using a Hydrogen Gas-Containing Preservation Solution and Adequate Immunosuppression in a Miniature Pig Model
Nishi K, Iwai S, Tajima K, Okano S, Sano M, Kobayashi E. · Frontiers in Immunology. 2021;11:626295.
What kind of evidence is this?
Preclinical
Controlled donor-after-cardiac-death kidney-transplant study in mature microminiature pigs
Kidney and urinary health
Other forms
Not reported in this record.
Not reported in this record.
Methods at a glance
Four donor and eight recipient microminiature pigs; ischemic kidneys were transplanted across non-matched swine-leukocyte-antigen backgrounds with multidrug immunosuppression.
12 pigs overall. Recipient groups were hydrogenated preservation solution n=4, non-hydrogenated solution n=3 and one living-donor reference recipient n=1.
Ten-minute rinse, 60 or 240 minutes of cold storage, then follow-up to 100 days or humane endpoint.
Donor kidneys were rinsed for ten minutes and stored for 60 or 240 minutes at 4°C in hydrogenated ETK preservation solution before transplantation.
H₂ dissolved in organ-preservation solution — H₂ only, not Brown's gas and not inhalation.
Dissolved H₂ was maintained at at least 1 ppm for four hours. The preparation paragraph prints an internal container-pressure value of '0.06 ppm', which is dimensionally inconsistent and is preserved as a source issue rather than corrected by inference.
Not applicable — dissolved H₂ organ-preservation solution, not gas inhalation.
No O₂ was co-delivered as part of the H₂ intervention.
Non-hydrogenated ETK after the same 20-minute donor ischemia, plus one living-donor reference kidney.
Outcomes and reported result
Survival, urine output, BUN/creatinine, renal blood flow and resistive index, CT perfusion, thrombosis, histopathology, chronic rejection/fibrosis and syndecan-1.
Three of four hydrogenated-solution recipients reached 100 days; the fourth had major ureteral obstruction/intervention. All three non-hydrogenated ischemic-kidney recipients were sacrificed on days 3–7 with anuria, thrombosis and worsening kidney function. Long-term H₂ grafts had absent or mild chronic rejection, but the comparison was extremely small and not balanced for all surgical details.
The complete free PMC article, tables and supplement descriptions were checked for donor/recipient counts, preparation concentration, the printed unit inconsistency, storage schedules, survival and graft findings, complications, limitations, commercial funding and conflicts.
A reported association, difference or mechanism is not automatically a clinical benefit. Null findings, outcome type, study design and precision all matter.
Cautions and applicability
Only four treated and three ischemic controls, one living reference, unknown SLA haplotypes, surgical/ischemic heterogeneity, major ureteral complication, extensive immunosuppression and limited mechanistic tissue assays. Doctors Man funded the work and helped devise the H₂-infusion system; two authors were medical advisers to the company.
Experimental marginal-kidney transplantation in mature miniature pigs; it does not establish human graft preservation or rejection prevention.
Not reported in this record.
Not reported in this record.
Not reported in this record.
No single-study GRADE certainty rating is assigned. Certainty is assessed by important outcome across a complete eligible evidence set, not by attaching a final grade to one source.
Sources and record status
PMID: 33679720 · DOI: 10.3389/fimmu.2020.626295
Free full article in PubMed Central.
Complete PMC article, supplementary descriptions and PubMed metadata; full-text extraction checked 9 August 2026.
2026-08-10