Perfusate Metabolomics Content and Expression of Tubular Transporters During Human Kidney Graft Preservation by Hypothermic Machine Perfusion.

BACKGROUND: Ischemia-related injury during the preimplantation period impacts kidney graft outcome. Evaluating these lesions by a noninvasive approach before transplantation could help us to understand graft injury mechanisms and identify potential biomarkers predictive of graft outcomes. This study aims to determine the metabolomic content of graft perfusion fluids and its dependence on preservation time and to explore whether tubular transporters are possibly involved in metabolomics variations. METHODS: Kidneys were stored on hypothermic perfusion machines. We evaluated the metabolomic profiles of perfusion fluids (n = 35) using liquid chromatography coupled with tandem mass spectrometry and studied the transcriptional expression of tubular transporters on preimplantation biopsies (n = 26), both collected at the end of graft perfusion. We used univariate and multivariate analyses to assess the impact of perfusion time on these parameters and their relationship with graft outcome. RESULTS: Seventy-two metabolites were found in preservation fluids at the end of perfusion, of which 40% were already present in the native conservation solution. We observed an increase of 23 metabolites with a longer perfusion time and a decrease of 8. The predictive model for time-dependent variation of metabolomics content showed good performance (R 2 = 76%, Q 2 = 54%, accuracy = 41%, and permutation test significant). Perfusion time did not affect the mRNA expression of transporters. We found no correlation between metabolomics and transporters expression. Neither the metabolomics content nor transporter expression was predictive of graft outcome. CONCLUSIONS: Our results call for further studies, focusing on both intra- and extratissue metabolome, to investigate whether transporter alterations can explain the variations observed in the preimplantation period.

Impact of targeted hypothermia in expanded-criteria organ donors on recipient kidney-graft function: study protocol for a multicentre randomised controlled trial (HYPOREME).

INTRODUCTION: Expanded-criteria donors (ECDs) are used to reduce the shortage of kidneys for transplantation. However, kidneys from ECDs are associated with an increased risk of delayed graft function (DGF), a risk factor for allograft loss and mortality. HYPOREME will be a multicentre randomised controlled trial (RCT) comparing targeted hypothermia to normothermia in ECDs, in a country where the use of machine perfusion for organ storage is the standard of care. We hypothesise that hypothermia will decrease the incidence of DGF. METHODS AND ANALYSIS: HYPOREME is a multicentre RCT comparing the effect on kidney function in recipients of targeted hypothermia (34°C-35°C) and normothermia (36.5°C-37.5°C) in the ECDs. The temperature intervention starts from randomisation and is maintained until aortic clamping in the operating room. We aim to enrol 289 ECDs in order to analyse the kidney function of 516 recipients in the 53 participating centres. The primary outcome is the occurrence of DGF in kidney recipients, defined as a requirement for renal replacement therapy within 7 days after transplantation (not counting a single session for hyperkalemia during the first 24 hours). Secondary outcomes include the proportion of patients with individual organs transplanted in each group; the number of organs transplanted from each ECD and the vital status and kidney function of the recipients 7 days, 28 days, 3 months and 1 year after transplantation. An interim analysis is planned after the enrolment of 258 kidney recipients. ETHICS AND DISSEMINATION: The trial was approved by the ethics committee of the French Intensive Care Society (CE-SRLF-16-07) on 26 April 2016 and by the competent French authorities on 20 April 2016 (Comité de Protection des Personnes-TOURS-Région Centre-Ouest 1, registration #2016-S3). Findings will be published in peer-reviewed journals and presented during national and international scientific meetings. TRIAL REGISTRATION NUMBER: NCT03098706.

Impact of the duration of normothermic regional perfusion on the results of liver transplant from controlled circulatory death donors: A retrospective, multicentric study.

In France, the program of controlled donation after circulatory death (cDCD) was established with routine use of in situ normothermic regional perfusion (NRP). There is currently no consensus on its optimal duration. The purpose was to assess the impact of NRP duration on liver graft function and biliary outcomes. One-hundred and fifty-six liver recipients from NRP-cDCD donors from six French centers between 2015 and 2019 were included. Primary endpoint was graft function assessed by early allograft dysfunction (EAD, according to Olthoff's criteria) and MEAF (model for early allograft function) score. Overall, three (1.9%) patients had primary non-function, 30 (19.2%) patients experienced EAD, and MEAF score was 7.3 (±1.7). Mean NRP duration was 179 (±43) min. There was no impact of NRP duration on EAD (170±44 min in patients with EAD vs. 181±42 min in patients without, P = .286). There was no significant association between NRP duration and MEAF score (P = .347). NRP duration did neither impact on overall biliary complications nor on non-anastomotic biliary strictures (overall rates of 16.7% and 3.9%, respectively). In conclusion, duration of NRP in cDCD donors does not seem to impact liver graft function and biliary outcomes after liver transplantation. A 1 to 4-h perfusion represents an optimal time window.

Ex vivo perfusion of the donor heart: Preliminary experience in high-risk transplantations.

BACKGROUND: The number of heart transplantations (HTs) has decreased in France since 2017 (-5%/year) despite a stable rate of patients referred on the waiting list. Ex vivo heart perfusion (EVHP) is an innovative approach for organ preservation, reducing graft ischaemic time and facilitating continuous organ monitoring before transplantation. AIM: To report our preliminary experience of seven donor hearts preserved with EVHP, including the first heart resuscitated after circulatory-determined death in France. METHODS: Seven hearts were procured from donation after brain death (DBD) for HT or donation after circulatory-determined death (DCD) for research purposes (Protocol PFS20-004, Agence de la Biomédecine, La Plaine Saint-Denis, France). All grafts were preserved using the Organ Care System® (TransMedics Inc., Andover, MA, USA) for normothermic EVHP. Perfusion parameters were adjusted to achieve stable or decreasing arterial lactate trend consistent with suitability for organ transplantation. RESULTS: Indications for EVHP were assessment of a marginal graft in four cases, prolonged preservation in two cases (anticipated duration for retrieval of recipient's heart>3hours) and resuscitation after circulatory-determined death in one case. Median duration of EVHP was 270 (interquartile range 216-343) minutes. five were transplanted, with a median ex situ preservation time (ischaemic time+EVHP time) of 334 (interquartile range 326-444) minutes. The two other grafts were discarded for HT. Three recipients had extracorporeal life support after HT, and presented complete cardiac recovery within a week after HT. One patient died at day 11 because of septic shock. The 3-month survival rate was 75% among recipients. Three months after HT, the left ventricular ejection fraction was>60% in all cases. CONCLUSIONS: EVHP enabled safe prolonged preservation and assessment of marginal grafts. This approach provides an opportunity to expand the donor pool by resuscitating grafts from donors with extended criteria, including controlled DCD.

Bacterial Pneumonia in Brain-Dead Patients: Clinical Features and Impact on Lung Suitability for Donation.

OBJECTIVES: To appraise the epidemiological features of bacterial pneumonia and its impact on lung suitability for donation in brain-dead patients managed with protective ventilatory settings. DESIGN: Retrospective observational study. SETTING: Six ICUs from two university-affiliated hospitals. PATIENTS: Brain-dead adult patients managed in the participating ICUs over a 4-year period. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Among the 231 included patients, 145 (62.8%) were classified as ideal or extended-criteria potential lung donors at ICU admission and the remaining 86 patients having baseline contraindication for donation. Culture-proven aspiration pneumonia and early-onset ventilator-associated pneumonia occurred in 54 patients (23.4%) and 15 patients (6.5%), respectively (overall pneumonia incidence, 29.9%). Staphylococcus aureus and Enterobacterales were the most common pathogens. Using mixed-effects Cox proportional hazard models, age (adjusted hazard ratio, 0.98; 95% CI [0.96-0.99]), anoxic brain injury (3.55 [1.2-10.5]), aspiration (2.29 [1.22-4.29]), and not receiving antimicrobial agents at day 1 (3.56 [1.94-6.53]) were identified as independent predictors of pneumonia occurrence in the whole study population. Analyses restricted to potential lung donors yielded similar results. Pneumonia was associated with a postadmission decrease in the PaO2/FIO2 ratio and lower values at brain death, in the whole study population (estimated marginal mean, 294 [264-323] vs 365 [346-385] mm Hg in uninfected patients; p = 0.0005) as in potential lung donors (299 [248-350] vs 379 [350-408] mm Hg; p = 0.04; linear mixed models). Lungs were eventually retrieved in 31 patients (34.4%) among the 90 potential lung donors with at least one other organ harvested (pneumonia prevalence in lung donors (9.7%) vs nondonors (49.2%); p = 0.0002). CONCLUSIONS: Pneumonia occurs in one-third of brain-dead patients and appears as the main reason for lung nonharvesting in those presenting as potential lung donors. The initiation of antimicrobial prophylaxis upon the first day of the ICU stay in comatose patients with severe brain injury could enlarge the pool of actual lung donors.