Transplantation of a beating heart: A first in man

Metabolomics Differences of the Donor Livers Between In Situ and Ex Situ Conditions During Ischemia-free Liver Transplantation

BACKGROUND

Ischemia-free liver transplantation (IFLT) has been innovated to avoid graft ischemia during organ procurement, preservation, and implantation. However, the metabolism activity of the donor livers between in the in situ and ex situ normothermic machine perfusion (NMP) conditions, and between standard criteria donor and extend criteria donor remains unknown.

METHODS

During IFLT, plasma samples were collected both at the portal vein and hepatic vein of the donor livers in situ during procurement and ex situ during NMP. An ultra-high performance liquid chromatography-mass spectrometry was conducted to investigate the common and distinct intraliver metabolite exchange.

RESULTS

Profound cysteine and methionine metabolism, and aminoacyl-tRNA biosynthesis were found in both in situ and ex situ conditions. However, obvious D-arginine and D-ornithine metabolism, arginine and proline metabolism were only found in the in situ condition. The suppressed activities of the urea cycle pathway during ex situ condition were confirmed in an RNA expression level. In addition, compared with extend criteria donor group, standard criteria donor group had more active intraliver metabolite exchange in metabonomics level. Furthermore, we found that the relative concentration of p-cresol, allocystathionine, L-prolyl-L-proline in the ex situ group was strongly correlated with peak alanine aminotransferase and aspartate aminotransferase at postoperative days 1-7.

CONCLUSIONS

In the current study, we show the common and distinct metabolism activities during IFLT. These findings might provide insights on how to modify the design of NMP device, improve the perfusate components, and redefine the criteria of graft viability.

Ischemia-free organ transplantation - a review

PURPOSE OF REVIEW

Organ transplantation is one of the miracles in medicine in the 20th century. However, in the current practice, all the donor organs suffer from ischemia/reperfusion injury (IRI), which compromise transplant outcomes and limits organ availability. Continuous efforts have been made in organ machine perfusion to ameliorate IRI. In 2017, ischemia-free organ transplantation (IFOT) was first proposed with the aim of complete avoidance of IRI in organ transplantation. The purpose of this review is to highlight the latest progresses in IFOT.

RECENT FINDINGS

The feasibility of IFOT has been validated in liver, kidney, and heart transplantation. The results of the first nonrandomized controlled study demonstrate that ischemia-free liver transplantation (IFLT) may improve transplant outcomes and increase organ availability. Furthermore, laboratory results, including the absence of the characteristic pathological changes, gene transcription and metabolic reprogramming, as well as sterile inflammation activation in IFLT grafts, suggest the virtual avoidance of graft IRI in IFLT.

SUMMARY

IFOT might change the current practice by abrogating graft IRI. IFOT also provides a unique model to investigate the interaction between allograft IRI and rejection. The next steps will be to simplify the technique, make long-distance transportation possible and evaluate cost-effectiveness.