Abdominal Normothermic Regional Perfusion after Donation after Circulatory Death Improves Pancreatic Islet Isolation Yield.

Abdominal Normothermic Regional Perfusion (aNRP) is an in-situ normothermic oxygenated donor perfusion technique before procurement during controlled donation after circulatory death (cDCD) procedures and allows for organ quality evaluation. There are few data on the effect of aNRP on pancreatic islet isolation and subsequent transplantation outcomes. We aim to evaluate the impact of aNRP on cDCD pancreatic islet isolation and transplantation. A retrospective analysis was performed on pancreatic islet isolation outcomes from aNRP, cDCD, and Donation after Brain death (DBD) pancreases. Isolations were compared to previous donor age (60-75) matched isolations. Islet function was asses by a dynamic Glucose Stimulated Insulin Secretion (dGSIS). Donor baseline characteristics did not differ among groups. Isolations from aNRP pancreases (471,739 IEQ [655,435 - 244,851]) yielded more islets compared to cDCD (218,750 IEQ [375,951 - 112,364, p<0.01) and to DBD (206,522 IEQ [385,544 - 142,446, p=0.03) pancreases. dGSIS tests in seven aNRP islet preparations showed a mean stimulation index of 4.91, indicating good functionality. Bilirubin and alanine aminotransferase during aNRP correlated with islet yield (r2=0.685, p=0.002; r2=0.491, p=0.016 respectively). Islet isolation after aNRP in cDCD donors results in a high islet yield with viable functional islets. aNRP could increase the utilization of pancreases for islet transplantation.

Tensions between end-of-life care and organ donation in controlled donation after circulatory death: ICU healthcare professionals experiences.

BACKGROUND: The development of controlled donation after circulatory death (cDCD) is both important and challenging. The tension between end-of-life care and organ donation raises significant ethical issues for healthcare professionals in the intensive care unit (ICU). The aim of this prospective, multicenter, observational study is to better understand ICU physicians' and nurses' experiences with cDCD. METHODS: In 32 ICUs in France, ICU physicians and nurses were invited to complete a questionnaire after the death of end-of-life ICU patients identified as potential cDCD donors who had either experienced the withdrawal of life-sustaining therapies alone or with planned organ donation (OD(-) and OD( +) groups). The primary objective was to assess their anxiety (State Anxiety Inventory STAI Y-A) following the death of a potential cDCD donor. Secondary objectives were to explore potential tensions experienced between end-of-life care and organ donation. RESULTS: Two hundred six ICU healthcare professionals (79 physicians and 127 nurses) were included in the course of 79 potential cDCD donor situations. STAI Y-A did not differ between the OD(-) and OD( +) groups for either physicians or nurses (STAI Y-A were 34 (27-38) in OD(-) vs. 32 (27-40) in OD( +), p = 0.911, for physicians and 32 (25-37) in OD(-) vs. 39 (26-37) in OD( +), p = 0.875, for nurses). The possibility of organ donation was a factor influencing the WLST decision for nurses only, and a factor influencing the WLST implementation for both nurses and physicians. cDCD experience is perceived positively by ICU healthcare professionals overall. CONCLUSIONS: cDCD does not increase anxiety in ICU healthcare professionals compared to other situations of WLST. WLST and cDCD procedures could further be improved by supporting professionals in making their intentions clear between end-of-life support and the success of organ donation, and when needed, by enhancing communication between ICU physician and nurses. TRIAL REGISTRATION: This research was registered in ClinicalTrials.gov (Identifier: NCT05041023, September 10, 2021).

Outcomes of Donation After Circulatory Death (DCD) and Ex-Vivo Lung Perfusion (EVLP) Lung Transplantation.

BACKGROUND: Donation after circulatory death (DCD) and ex-vivo lung perfusion (EVLP) have been adopted to expand the donor pool in lung transplantation, but outcomes data have been conflicting. This study explores mid-term outcomes of DCD lung transplantation in the modern era, with a focus on EVLP and risk factors for graft failure. METHODS: The United Network for Organ Sharing (UNOS) database was queried for adult lung transplants from 1/1/2015 to 3/1/2023. Loss to follow-up, multiorgan and prior lung transplants were excluded. DCD vs DBD (donation after brain death) lung transplants were compared, with subgroup analysis +/- EVLP. Outcomes were survival and postoperative complications. Overall survival was analyzed separately for an early era (2015-2018) and modern era (2019-2023). RESULTS: The study included 1103 DCD (221 with EVLP, and 882 without) and 17973 donation after brain death (DBD) lung transplants (524 with EVLP, and 17449 without). Median follow-up was 3 years. DCD donors were less likely to be CDC high risk (19.3% vs 24.1%, p<0.001), have purulence on bronchoscopy (13.3% vs 18.3%, p<0.001) or infiltrates on chest x-ray (66.7% vs 67.8%, p=0.013). EVLP was more likely to be used for DCD transplants (20.0% vs 2.9%, p<0.001). After transplant, DCD recipients were more likely to be reintubated (24.3% vs 18.5%, p<0.001) and require ECMO within 72 hours (14.9% vs 7.8%, p<0.001), and DCD donation was an independent risk factor for these complications on multivariable logistic regression. Overall survival did not differ significantly between DCD and DBD transplants on adjusted survival analysis in the early or modern era (p=0.774 and p=0.468 respectively). On multivariable Cox regression, DCD and EVLP were not independent risk factors for mortality. On subgroup analysis, the DCD+EVLP cohort had significantly worse survival in the modern era, which remained significant after adjusting for donor and recipient factors (p=0.005). EVLP was an independent risk factor for graft failure in the DCD cohort (HR 1.33, 95% CI 1.00-1.77, p=0.047), but did not significantly affect DBD graft survival (p=0.870). Risk factors for graft failure and mortality in the DCD+EVLP cohort included pulmonary hypertension (HR 77.5, 95% CI 6.15-979, p<0.001), transfusion prior to transplant (HR 2.60, 95% CI 1.07-6.31, p=0.035), elevated creatinine (HR 2.82, 95% CI 1.34-5.90, p=0.006), and higher allocation score (HR 1.02, 95% CI 1.00-1.04, p=0.017) CONCLUSION: Study findings suggest increased risks of mortality and perioperative complications following transplantation with DCD lungs that have undergone EVLP. DCD lung transplantation without EVLP confers equivalent survival but with some increase in perioperative complications. Further investigation and careful recipient selection is warranted to optimize the use of these extended criteria donors in the modern era.

The Rapidly Evolving Landscape of DCD Heart Transplantation.

PURPOSE OF REVIEW: To summarise current international clinical outcomes from donation after circulatory death heart transplantation (DCD-HT); discuss procurement strategies, their impact on outcomes and overall organ procurement; and identify novel approaches and future areas for research in DCD-HT. RECENT FINDINGS: Globally, DCD-HT survival outcomes (regardless of procurement strategy) are comparable to heart transplantation from brain dead donors (BDD). Experience with normothermic machine perfusion sees improvement in rates of primary graft dysfunction. Techniques have evolved to reduce cold ischaemic exposure to directly procured DCD hearts, though controlled periods of cold ischaemia can likely be tolerated. There is interest in hypothermic machine perfusion (HMP) for directly procured DCD hearts, with promising early results. Survival outcomes are firmly established to be equivalent between BDD and DCD-HT. Procurement strategy (direct procurement vs. regional perfusion) remains a source of debate. Methods to improve allograft warm ischaemic tolerance are of interest and will be key to the uptake of HMP for directly procured DCD hearts.

Early Renal Outcomes Following Heart Transplantation Using Organs Procured After Circulatory Death.

BACKGROUND: Transplantation using hearts obtained through donation after circulatory death (DCD) is increasing, but data on recipient renal outcomes are limited. METHODS AND RESULTS: Patients at a single institution who underwent heart transplantation using organs procured through DCD or donation after brain death (DBD) from April 2016 to August 2022 were included in this retrospective cohort study. Hemodynamic measures were collected via right heart catheterization performed 1 week after transplantation. Posttransplantation renal outcomes included estimated glomerular filtration rate at 1 week, 4 weeks, and 16 weeks, and the incidence of acute kidney injury (AKI) and renal replacement therapy within 1 week. The analysis included 225 patients (55 recipients of DCD). Baseline characteristics were comparable between recipients of DCD and DBD. Renal outcomes within 1 week posttransplantation in recipients of DCD were similar to recipients of DBD, including percent change in estimated glomerular filtration rate (-37.9% [-58.6 to -6.2] versus -31.9% [-52.4 to -9.9]; P=0.91), incidence of AKI (47.3% versus 46.5%; P>0.99) and incidence of renal replacement therapy (3.6% versus 4.7%; P>0.99). Recipients of DCD with AKI within 1 week ("early AKI") did not recover to baseline estimated glomerular filtration rate (75.8 [60.2-91.3] mL/min per 1.73 m2) by week 16 (59.3 [46.9-73.6] mL/min per 1.73 m2; P=0.002), whereas recipients without early AKI exhibited comparable estimated glomerular filtration rate to baseline by week 4 (84.5 [70.8-98.5] mL/min per 1.73 m2; P=0.084). Similar trends were observed in recipients of DBD. CONCLUSIONS: Recipients of DCD demonstrated similar renal outcomes compared with recipients of DBD, supporting the ongoing use of DCD transplantation. Early AKI was associated with persistent renal dysfunction for recipients of both DCD and DBD.

Loss of Nr4a1 ameliorates endothelial cell injury and vascular leakage in lung transplantation from circulatory-death donor.

BACKGROUND: Ischemia-reperfusion injury (IRI) stands as a major trigger for primary graft dysfunction (PGD) in lung transplantation (LTx). Especially in LTx from donation after cardiac death (DCD), effective control of IRI following warm ischemia (WIRI) is crucial to prevent PGD. This study aimed to identify the key factors affecting WIRI in LTx from DCD. METHODS: Previously reported RNA-sequencing dataset of lung WIRI was reanalyzed to identify nuclear receptor subfamily 4 group A member 1 (NR4A1) as the immediate early gene for WIRI. Dynamics of NR4A1 expression were verified using a mouse hilar clamp model. To investigate the role of NR4A1 in WIRI, a mouse model of LTx from DCD was established using Nr4a1 knockout (Nr4a1-/-) mice. RESULTS: NR4A1 was located around vascular cells, and its protein levels in the lungs increased rapidly and transiently during WIRI. LTｘ from Nr4a1-/- donors significantly improved pulmonary graft function compared to wild-type donors (P < 0.001). Histological analysis showed decreased microvascular endothelial cell death (P = 0.007), neutrophil infiltration (P < 0.001), and albumin leakage (P < 0.001). Evans blue permeability assay demonstrated maintained pulmonary microvascular barrier integrity in grafts from Nr4a1-/- donors, correlating with diminished pulmonary edema (P < 0.001). However, NR4A1 did not significantly affect the inflammatory response during WIRI, and IRI was not suppressed when a wild-type donor lung was transplanted into the Nr4a1-/- recipient. CONCLUSIONS: Donor NR4A1 plays a specialized role in the positive regulation of endothelial cell injury and microvascular hyperpermeability. These findings demonstrate the potential of targeting NR4A1 interventions to alleviate PGD and improve outcomes in LTx from DCD.

Early outcomes in heart transplantation using donation after circulatory death donors in patients bridged with durable left ventricular assist devices.

OBJECTIVE: Donation after circulatory death heart transplantation potentially increases donor allografts, especially for patients with lower listing status. We assessed the outcomes of donation after circulatory death heart transplantation in patients bridged with durable left ventricular assist devices. METHODS: The United Network for Organ Sharing database was queried for adult heart transplants using donation after circulatory death donors from 2019 to 2022. Patients were stratified between those with durable left ventricular assist devices and those with intra-aortic balloon pump, inotropic, or no bridging support (control group). Primary outcome was 1-year mortality. Secondary end points were hospital length of stay, stroke, pacemaker implantation, dialysis, and acute rejection before discharge. RESULTS: A total of 160 left ventricular assist device recipients and 311 control recipients met study inclusion criteria. Recipients bridged with left ventricular assist devices were younger (55 vs 58 years, P < .001) with lower body mass index (28.3 vs 30.3, P < .001), longer waitlist times (112 vs 34 days, P < .001), longer out of body times (5.7 vs 4.6 hours, P < .001), and less frequent normothermic regional perfusion (31% vs 40%, P = .049). Patients with left ventricular assist devices commonly underwent transplantation at United Network for Organ Sharing status 3 and 4 (92%), whereas control patients underwent transplantation at status 2 (27%), status 3 (10%), status 4 (30%), or status 6 (30%). Kaplan-Meier analysis showed no difference in 1-year mortality between groups (P = .34). However, acute rejection was higher in the unadjusted left ventricular assist device cohort (26% vs 13%, P < .001). On multivariable logistic regression, left ventricular assist device was an independent predictor of acute rejection (odds ratio, 2.21, 95% CI, 1.32-3.69, P = .002). CONCLUSIONS: Durable left ventricular assist devices may be associated with a higher risk of developing an early inflammatory response in donation after circulatory death heart transplantation; however, 1-year survival was similar between groups.

Expanding Horizons in Cardiac Transplant: Efficacy and Outcomes of Circulatory and Brain Death Donor Hearts in a Newly Implemented Cardiac Transplant Program with Limited Donor Accessibility and a Literature Review.

(1) Background: Cardiac donation after circulatory death (DCD) is an emerging paradigm in organ transplantation. However, this technique is recent and has only been implemented by highly experienced centers. This study compares the characteristics and outcomes of thoraco-abdominal normothermic regional perfusion (TANRP) and static cold-storage DCD and traditional donation after brain death (DBD) cardiac transplants (CT) in a newly stablished transplant program with restricted donor availability. (2) Method: We performed a retrospective, single-center study of all adult patients who underwent a CT between November 2019 and December 2023, with a follow-up conducted until August 2024. Data were retrieved from medical records. A review of the current literature on DCD CT was conducted to provide a broader context for our findings. The primary outcome was survival at 6 months after transplantation. (3) Results: During the study period, 76 adults (median age 56 years [IQR: 50-63 years]) underwent CT, and 12 (16%) were DCD donors. DCD donors had a similar age (46 vs. 47 years, p = 0.727), were mostly male (92%), and one patient had left ventricular dysfunction during the intraoperative DCD process. There were no significant differences in recipients' characteristics. Survival was similar in the DCD group compared to DBD at 6 months (100 vs. 94%) and 12 months post-CT survival (92% vs. 94%), p = 0.82. There was no primary graft dysfunction in the DCD group (9% in DBD, p = 0.581). The median total hospital stay was longer in the DCD group (46 vs. 21 days, p = 0.021). An increase of 150% in transplantation activity due to DCD was estimated. (4) Conclusions: In a new CT program that utilized older donors and included recipients with similar illnesses and comorbidities, comparable outcomes between DCD and DBD hearts were observed. DCD was rapidly incorporated into the transplant activity, demonstrating an expedited learning curve and significantly increasing the availability of donor hearts.

The current landscape of in situ and ex situ machine perfusion utilization for liver grafts from cardiac donation after circulatory death donors in the US.

Donation after circulatory death (DCD) is driving the increase in deceased organ donors in the United States. Normothermic regional perfusion (NRP) and ex situ machine perfusion (es-MP) have been instrumental in improving liver transplant outcomes and graft utilization. This study examines the current landscape of liver utilization from cardiac DCD donors in the United States. Using the United Network for Organ Sharing Standard Transplant Analysis and Research file, all adult (≥18 years old) DCD donors in the United States from which the heart was used for transplantation from October 1, 2020, to September 30, 2023, were compared by procurement technique (NRP versus super rapid recovery [SRR]) and storage strategy (es-MP versus static cold storage). One hundred eighty-eight livers were transplanted from 309 thoracoabdominal NRP donors (61% utilization) versus 305 (56%) liver transplants from 544 SRR donors. es-MP was used in 20% (n = 38) of NRP cases versus 32% (98) of SRR cases. Of the liver grafts, 281 (59%) were exposed to NRP, es-MP, or both. While there is widespread utilization of machine perfusion, more research is needed to determine optimal graft management strategies, particularly concerning the use of multiple technologies in complementary ways. More complete data collection is necessary at a national level to address these important research questions.

Expression of c-jun/c-fos mRNA Indicates Persistent Myocardial Stretch During Asphyxia-Induced Cardiac Arrest.

Right ventricular dysfunction is a key clinical issue for the viability of donation-after-circulatory-death (DCD) heart transplantation. DCD hearts with volume overload have the potential to exhibit aggravated right ventricular dysfunction following heart transplantation. The c-jun/c-fos mRNAs are genes that immediately respond to myocardial cell stretch. We assessed myocardial cell stretch during asphyxia-induced cardiac arrest by measuring c-jun/c-fos mRNA expression levels. The trachea was dissected and ligated to initiate asphyxiation in anesthetized Wistar rats under paralyzed ventilation. The hearts were harvested at 4 time points: 0, 15, 30, and 45 minutes after the termination of ventilation. Free walls of the right and left ventricles and the interventricular septum were sectioned. Total RNA was extracted from these tissues, and cDNA was synthesized using reverse transcription. The c-jun/c-fos mRNA expression levels were quantified using the droplet digital polymerase chain reaction method. In the left ventricle, c-jun/c-fos expression levels rapidly increased at 15 minutes, but the expression levels returned to the baseline level at 30 minutes after tracheal ligation. In contrast, in the right ventricle, c-jun/c-fos expression levels gradually increased and peaked 30 minutes after tracheal ligation. Myocardial cell stretching in the right ventricle is prolonged after asphyxia-induced cardiac arrest compared to that in the left ventricle, which may lead to right ventricular dysfunction after DCD heart transplantation.

Normothermic Regional Perfusion in Controlled Donation After Circulatory Death Liver Transplantation: A Systematic Review and Meta-Analysis.

Liver grafts from controlled donation after circulatory death (cDCD) donors have lower utilization rates due to inferior graft and patient survival rates, largely attributable to the increased incidence of ischemic cholangiopathy, when compared with grafts from brain dead donors (DBD). Normothermic regional perfusion (NRP) may improve the quality of cDCD livers to allow for expansion of the donor pool, helping to alleviate the shortage of transplantable grafts. A systematic review and metanalysis was conducted comparing NRP cDCD livers with both non-NRP cDCD livers and DBD livers. In comparison to non-NRP cDCD outcomes, NRP cDCD grafts had lower rates of ischemic cholangiopathy [RR = 0.23, 95% CI (0.11, 0.49), p = 0.0002], primary non-function [RR = 0.51, 95% CI (0.27, 0.97), p = 0.04], and recipient death [HR = 0.5, 95% CI (0.36, 0.69), p < 0.0001]. There was no difference in outcomes between NRP cDCD donation compared to DBD liver donation. In conclusion, NRP improved the quality of cDCD livers compared to their non-NRP counterparts. NRP cDCD livers had similar outcomes to DBD grafts. This provides further evidence supporting the continued use of NRP in cDCD liver transplantation and offers weight to proposals for its more widespread adoption.

The Differential Impact of Early Graft Dysfunction in Kidney Donation After Brain Death and After Circulatory Death: Insights from the Dutch National Transplant Registry.

Kidneys donated after circulatory death (DCD) perform similarly to kidneys donated after brain death (DBD). However, the respective incidences of delayed graft function (DGF) differ. This questions the donor type-specific impact of early graft function on long-term outcome. Using competing risk and cox regression analysis, we compared death-censored graft loss between types of early graft function: DGF (temporary dialysis dependency started within seven days after transplantation), slow graft function (SGF, three-day plasma creatinine decline less than 10% per day), and immediate graft function (IGF). In 1061 DBD and 1605 DCD graft recipients (January 2014 until January 2023), graft survival was similar. DGF was associated with death-censored graft loss in DBD and DCD (adjusted hazard ratios [aHR]: DGF in DBD: 1.79 [1.04- 2.91], p = 0.027, DGF in DCD: 1.84 [1.18 - 2.87], p = 0.008; Reference: no DGF). SGF was associated with death-censored graft loss in DBD, but not significantly in DCD (aHR DBD: 2.82 (1.34 - 5.93), p = 0.007, and DCD: 1.54 (0.72 - 3.35), p = 0.262; Reference: IGF). Early graft dysfunction has a differential impact on graft outcome in DBD and DCD. The differences between DBD and DCD should be accounted for in research and the clinic.

Procurement Trends, Indications, and Outcomes of Heart-Lung Transplantation in the Contemporary Era.

BACKGROUND: Evolving trends in organ procurement and technological innovation prompted an investigation into recent trends, indications, and outcomes following combined heart-lung transplantation (HLTx). METHODS: The United Network for Organ Sharing database was queried for all adult (≥18 years) HLTx performed between July 1, 2013 and June 30, 2023. Patients with previous transplants were excluded. The primary endpoint was the effect of donor, recipient, and transplantation characteristics on 1- and 5-year survival. Secondary analyses included a comparison of HLTx at high- and low-volume centers, an assessment of HLTx following donation after circulatory death (DCD), and an evaluation of HLTx volume over time. Cox proportional-hazards models were used to assess factors associated with mortality. Temporal trends were evaluated with linear regression. RESULTS: After exclusions, 319 patients were analyzed, of whom 5 (1.6%) were DCD. HLTx volume increased from 2013 to 2023 (p < 0.001). One- and 5-year survival following HLTx was 84.0% and 59.5%, respectively. One-year survival was higher for patients undergoing HLTx at a high-volume center (88.3% vs. 77.9%; p = 0.012). After risk adjustment, extracorporeal membrane oxygenation support 72 h posttransplant and predischarge dialysis were associated with increased 1-year mortality (HR = 3.19, 95% CI = 1.86-5.49 and HR = 3.47, 95% CI = 2.17-5.54, respectively) and 5-year mortality (HR = 2.901, 95% CI = 1.679-5.011 and HR = 3.327, 95% CI = 2.085-5.311, respectively), but HLTx at a high-volume center was not associated with either. CONCLUSIONS: HLTx volume has resurged, with DCD HLTx emerging as a viable procurement strategy. Factors associated with 1- and 5-year survival may be used to guide postoperative management following HLTx.

Donation After Circulatory Death following Withdrawal of Life-Sustaining Treatments. Are We Ready to Break the Dead Donor Rule?

A fundamental criterion considered essential to deem the procedure of vital organ procurement for transplantation ethical is that the donor must be dead, as per the Dead Donor Rule (DDR). In the case of Donation after Circulatory Death (DCD), is the donor genuinely dead? The main aim of this article is to clarify this uncertainty, which primarily arises from the fact that in DCD, death is determined based on cardiac criteria (Circulatory Death, CD), rather than neurological criteria (Brain Death, BD), and that to allow the procurement procedure, physicians reperfuse the organs in an assisted manner. To ensure that the cessation of circulation leads to the irreversible loss of brain functions, DCD regulations require that physicians wait a certain period after CD before commencing vital organ procurement. However, during this "no-touch period," the organs are at risk of damage, potentially rendering them unsuitable for transplantation. When DCD is performed on patients whose CD follows a Withdrawal of Life-Sustaining Treatment (WLST) (DCD Maastricht III category), how long should the no-touch period last? Does its existence really make sense? Does beginning the procedure of vital organ procurement immediately after WLST constitute a violation of the DDR that can be ethically justified? The discussion aims to provide arguments in support of the non-absoluteness of the DDR.

Liver function maximum capacity test during normothermic regional perfusion predicts graft function after transplantation.

Purpose: In an effort to reduce waitlist mortality, extended criteria donor organs, including those from donation after circulatory death (DCD), are being used with increasing frequency. These donors carry an increased risk for postoperative complications, and balancing donor-recipient risks is currently based on generalized nomograms. Abdominal normothermic regional perfusion (aNRP) enables individual evaluation of DCD organs, but a gold standard to determine suitability for transplantation is lacking. This study aimed to incorporate individualized and predictive measurements of the liver maximum capacity (LiMAx) test to objectively grade liver function during aNRP and prevent post-op complications. Methods: aNRP was performed to salvage 18 DCD liver grafts, otherwise discarded. Continuous variables were presented as the median with the interquartile range. Results: The liver function maximum capacity (LiMAx) test was successfully performed within the aNRP circuit in 17 aNRPs (94%). Donor livers with good lactate clearance during aNRP demonstrated significantly higher LiMAx scores (396 (301-451) µg/kg/h versus those who did not 105 (70-158) µg/kg/h; P = 0.006). This was also true for manifesting stress hyperglycemia > 20 mmol/l (P = 0.032). LiMAx score correlated with alanine aminotransferase (ALT; R = - 0.755) and aspartate transaminase (AST; R = - 0.800) levels during perfusion and distinguished livers that were selected for transplantation (397 (346-453) µg/kg/h) from those who were discarded (155 (87-206) µg/kg/h; P < 0.001). Twelve livers were accepted for transplantation, blinded for LiMAx results, and all had LiMAx scores of > 241 µg/kg/h. Postoperatively, LiMAx during aNRP displayed correlation with 24-h lactate levels. Conclusions: This study shows for the first time the feasibility to assess liver function during aNRP in individual donor livers. LiMAx presents an objective tool to predict donor liver function and risk of complications in the recipient, thus enabling individualized matching of donor livers for an individual recipient. The LiMAx test may present a valuable test for the prediction of donor liver function, preventing post-transplant complication, and personalizing the selection of donor livers for individual recipients. Supplementary Information: The online version contains supplementary material available at 10.1007/s13167-024-00371-7.

Air-ventilated normothermic mechanical perfusion improves susceptibility to donation after circulatory death and cold preservation-induced cholestatic liver injury through PPAR-γ/UGT1A1 axis.

End-ischemic normothermic mechanical perfusion (NMP) could provide a curative treatment to reduce cholestatic liver injury from donation after circulatory death (DCD) in donors. However, the underlying mechanism remains elusive. Our previous study demonstrated that air-ventilated NMP could improve functional recovery of DCD in a preclinical NMP rat model. Here, metabolomics analysis revealed that air-ventilated NMP alleviated DCD- and cold preservation-induced cholestatic liver injury, as shown by the elevated release of alanine aminotransferase (ALT), aspartate aminotransferase (AST), bilirubin, and γ-glutamyl transferase (GGT) in the perfusate (p < .05) and the reduction in the levels of bile acid metabolites, including ω-muricholic acid, glycohyodeoxycholic acid, glycocholic acid, and glycochenodeoxycholate (GCDC) in the perfused livers (p < .05). In addition, the expression of the key bile acid metabolism enzyme UDP-glucuronosyltransferase 1A1 (UGT1A1), which is predominantly expressed in hepatocytes, was substantially elevated in the DCD rat liver, followed by air-ventilated NMP (p < .05), and in vitro, this increase was induced by decreased GCDC and hypoxia-reoxygenation in the hepatic cells HepG2 and L02 (p < .05). Knockdown of UGT1A1 in hepatic cells by siRNA aggravated hepatic injury caused by GCDC and hypoxia-reoxygenation, as indicated by the ALT and AST levels in the supernatant. Mechanistically, UGT1A1 is transcriptionally regulated by peroxisome proliferator-activator receptor-γ (PPAR-γ) under hypoxia-physoxia. Taken together, our data revealed that air-ventilated NMP could alleviate DCD- and cold preservation-induced cholestatic liver injury through PPAR-γ/UGT1A1 axis. Based on the results from this study, air-ventilated NMP confers a promising approach for predicting and alleviating cholestatic liver injury through PPAR-γ/UGT1A1 axis.

Tuscany Normothermic Regional Perfusion Mobile Teams for Controlled Donation After Circulatory Death.

INTRODUCTION: To facilitate the implementation of controlled donation after circulatory death (cDCD) programs even in hospitals not equipped with a local extracorporeal membrane oxygenation (ECMO) team, some countries have launched a local cDCD network with an ECMO mobile team for normothermic regional perfusion (NRP). In the Tuscany region, in 2021, the Regional Transplant Authority launched a cDCD program to make the cDCD pathway feasible even in peripheral hospitals with NRP mobile teams, which were "converted" existing ECMO mobile teams, composed of highly skilled and experienced personnel. METHODS: We describe the Tuscany cDCD program, (2021-2023), for cDCD from peripheral hospitals with NRP mobile teams. RESULTS: Twenty-six cDCDs (26/40, 65%) came from peripheral hospitals. Following the launch of the cDCD program, cDCDs from peripheral hospitals increased, from 33% (2021) to 75% (2022 and 2023) of the overall cDCDs. The mean age was 63 years, with older donors (>75 years) in half the cases. The median warm ischemia time was 45 min (20 min are required by the Italian law for death certification), ranging from 35 to 59 min. Among the 20 livers retrieved and 18 kidneys retrieved, 16 livers, and 11 kidneys (single kidney transplantation) were transplanted, after ex vivo reperfusion, respectively. CONCLUSIONS: The use of NRP mobile teams proved to be feasible and safe in the management of cDCD in peripheral hospitals. No complications were reported with NRP despite the advanced age of most cDCDs.

Early U.S. Heart Transplant Experience With Normothermic Regional Perfusion Following Donation After Circulatory Death.

BACKGROUND: Heart transplantation following donation after circulatory death (DCD HT) has short-term survival outcomes comparable to donation after brain death and has led to a significant increase in transplantation volume. The U.S. experience with the normothermic regional perfusion (NRP) DCD HT procurement method has not been evaluated. OBJECTIVES: The aim of this study was to examine short-term outcomes associated with NRP vs direct procurement and perfusion (DPP) methods used during DCD HT in the United States. METHODS: The UNOS (United Network for Organ Sharing) registry was queried for all adult (age ≥18 years) heart recipients and corresponding donors of controlled DCD HT from January 2019-December 2023. Transplantations were stratified by NRP or DPP reperfusion methods. The primary outcome was overall survival. RESULTS: A total of 918 heart donors and recipients met inclusion criteria, including 622 (68%) DPP and 296 (32%) NRP transplantations. Unadjusted Kaplan-Meier survival analysis demonstrated improved short-term survival associated with NRP (log-rank P = 0.005). After adjustment, DCD HT with NRP was independently associated with improved survival (HR: 0.39 [95% CI: 0.22-0.70]; P = 0.002). A propensity-matched analysis similarly demonstrated a cumulative survival benefit to NRP (log-rank P = 0.006). CONCLUSIONS: In this largest national series of DCD HT procurement perfusion strategies, NRP is associated with improved short-term survival as compared with DPP. This study evaluates the U.S. early experience with DCD HT, and longer-term follow-up data are needed to further assess the impact of DPP and NRP methods on post-heart transplantation outcomes.

Protective effects of mesenchymal stem cells-derived extracellular vesicles against ischemia-reperfusion injury of hearts donated after circulatory death: Preliminary study in a pig model.

INTRODUCTION: Insufficient supply of cardiac grafts represents a severe obstacle in heart transplantation. Donation after Circulatory Death (DCD), in addition to conventional donation after brain death, is one promising option to overcome the organ shortage. However, DCD organs undergo an inevitable more extended period of warm unprotected ischemia between circulatory arrest and graft procurement. Mesenchymal stromal cell-derived extracellular vesicles (MSC-EVs) have shown remarkable protective effects against ischemia-reperfusion injury. Thus, we aimed to enhance grafts preservation from DCD donors, through treatment with MSC-EVs. METHODS: Female pigs were euthanized by barbiturate overdose and after 20 min of a flat EKG, the chest was opened, the heart harvested and subsequently connected to an extracorporeal perfusion machine. MSC-EVs, isolated by ion exchange chromatography, were added to the perfusion solution (1×1011 particles) and the heart was perfused for 2 h. Then, heart tissue biopsies were taken to assess histological changes, mitochondrial morphology, antioxidant enzyme activity and inflammation mediators' expression. Biochemical parameters of myocardial viability were assessed in the perfusate. RESULTS: The treatment with MSC-EVs significantly prevented mitochondria swelling, mitochondrial cristae loss and oxidative stress in cardiac tissue. The protective effect of MSC-EVs was confirmed by the delayed increase of the cardiac-specific enzymes CK and TnC in the perfusate and the reduction of caspase-3+ cells in tissue sections. CONCLUSION: MSC-EVs improve graft quality by preserving the mitochondrial ultrastructure protecting the myocardium against oxidative stress, reducing apoptosis of cardiac cells and preventing the increase of pro-inflammatory cytokines.