Optimal donation of kidney transplants after controlled circulatory death

The concept of immunothrombosis in pancreas transplantation

Early failure of a pancreatic allograft due to complete thrombosis has an incidence of approximately 10% and is the main cause of comorbidity in pancreas transplantation. Although several risk factors have been identified, the exact mechanisms leading to this serious complication are still unclear. In this review, we define the roles of the individual components involved during sterile immunothrombosis-namely endothelial cells, platelets, and innate immune cells. Further, we review the published evidence linking the main risk factors for pancreatic thrombosis to cellular activation and vascular modifications. We also explore the unique features of the pancreas itself: the vessel endothelium, specific vascularization, and relationship to other organs-notably the spleen and adipose tissue. Finally, we summarize the therapeutic possibilities for the prevention of pancreatic thrombosis depending on the different mechanisms such as anticoagulation, anti-inflammatory molecules, endothelium protectors, antagonism of damage-associated molecular patterns, and use of machine perfusion.

Normothermic Machine Perfusion and Normothermic Regional Perfusion of DCD Kidneys Before Transplantation: A Systematic Review

BACKGROUND

To overcome organ shortages, donation after circulatory death (DCD) kidneys are being increasingly used for transplantation. Prior research suggests that DCD kidneys have inferior outcomes compared with kidneys donated after brain death. Normothermic machine perfusion (NMP) and normothermic regional perfusion (NRP) may enhance the preservation of DCD kidneys and improve transplant outcomes. This study aimed to review the evidence surrounding NMP and NRP in DCD kidney transplantation.

METHODS

Two independent reviewers conducted searches for all publications reporting outcomes for NMP and NRP-controlled DCD kidneys, focusing on delayed graft function, primary nonfunction, graft function, graft survival, and graft utilization. Weighted means were calculated for all relevant outcomes and controls. Formal meta-analyses could not be conducted because of significant heterogeneity.

RESULTS

Twenty studies were included for review (6 NMP studies and 14 NRP studies). Delayed graft function rates seemed to be lower for NRP kidneys (24.6%) compared with NMP kidneys (54.3%). Both modalities yielded similar outcomes with respect to primary nonfunction (NMP 3.3% and NRP 5.6%), graft function (12-mo creatinine 149.3 μmol/L for NMP and 129.9 μmol/L for NRP), and graft utilization (NMP 83.3% and NRP 89%). Although no direct comparisons exist, our evidence suggests that both modalities have good short- and medium-term graft outcomes and high graft survival rates.

CONCLUSIONS

Current literature demonstrates that both NMP and NRP are feasible strategies that may increase donor organ utilization while maintaining acceptable transplant outcomes and likely improved outcomes compared with cold-stored DCD kidneys. Further research is needed to directly compare NRP and NMP outcomes.

Uterine Transplant Optimization From a Preclinical Donor Model With Controlled Cardiocirculatory Arrest

Background

Uterus transplantation from deceased donors offers a promising solution to the organ shortage, but optimal preservation methods are crucial for successful outcomes. Our primary objective is to conduct an initial assessment of the contribution of oxygenated hypothermic perfusion in uterine transplantation.

Methods

We performed a preclinical study on a porcine model of controlled donation after circulatory death (60 min warm ischemia). Ten uterus grafts were preserved for 12 h using static cold storage or hypothermic machine perfusion (VitaSmart device, perfusion pressure at 15 mm Hg). Subsequently, they were reperfused using ex vivo normothermic machine perfusion (Liverassist, perfusion pressure at 30 mm Hg) with oxygenated autologous blood to assess early ischemia/reperfusion injury. Not only resistance index assessment and oxygenation evaluation but also immunochemistry and gene expression analysis were performed.

Results

This study demonstrates the feasibility of using hypothermic machine perfusion for uterine graft preservation, showing improvements in reperfusion capacity (decrease of resistance indexes; P < 0.0001) and tissue oxygenation (higher oxygen level) compared with static cold storage.

Conclusions

These findings provide valuable insights for further research and refinement of uterine transplantation procedures.

Risk Factors for Adverse Outcomes in Kidney Transplants From Donors After Circulatory Death With Normothermic Regional Perfusion: A Systematic Analysis

BACKGROUND

This study examined 1071 adult primary kidney transplants from the French-controlled donation after the circulatory determination of death (cDCD) program, which uses normothermic regional perfusion (NRP), and involves short cold ischemia times (CIT) and constrained asystole times differing by donor age.

METHODS

Logistic regression identified risk factors for primary nonfunction (PNF), delayed graft function (DGF), and graft failure.

RESULTS

Risk factors for PNF included donor hypertension, admission for ischemic vascular stroke, and HLA DR mismatches. Risk factors for DGF included functional warm ischemia time >40 min, dialysis >2 y, recipient body mass index of 30 kg/m 2 or higher, recipient diabetes, and CIT >10 h. Risk factors for 1-y graft failure included donor hypertension, donor lung recovery, ostial calcification, recipient cardiovascular comorbidities, and HLA DR mismatches. A high donor estimated glomerular filtration rate protected against DGF and graft failure at 1-y. After adjustment restricted to recipient and graft factors and donor age, the risks of PNF, DGF, and graft failure increased with donor age up to 65 y and then remained stable.

CONCLUSIONS

The study suggests that cDCD kidney transplants are highly successful, but also that its outcomes are influenced by lung recovery, poor HLA DR matching, and warm ischemia times differing with donor age. Our study identified several risk factors for kidney transplantation failure after cDCD with systematic use of NRP and some of them seem as modifiable variables associated with cDCD transplant outcome.

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).

Prediction of delayed graft function by early salivary microbiota following kidney transplantation

Delayed graft function (DGF) is a frequently observed complication following kidney transplantation (KT). Our prior research revealed dynamic shifts in salivary microbiota post-KT with immediate graft function (IGF), yet its behavior during DGF remains unexplored. Five recipients with DGF and 35 recipients with IGF were enrolled. Saliva samples were collected during the perioperative period, and 16S rRNA gene sequencing was performed. The salivary microbiota of IGFs changed significantly and gradually stabilized with the recovery of renal function. The salivary microbiota composition of DGFs was significantly different from that of IGFs, although the trend of variation appeared to be similar to that of IGFs. Salivary microbiota that differed significantly between patients with DGF and IGF at 1 day after transplantation were able to accurately distinguish the two groups in the randomForest algorithm (accuracy = 0.8333, sensitivity = 0.7778, specificity = 1, and area under curve = 0.85), with Selenomonas playing an important role. Bacteroidales (Spearman's r =  - 0.4872 and p = 0.0293) and Veillonella (Spearmen's r =  - 0.5474 and p = 0.0125) were significantly associated with the serum creatinine in DGF patients. Moreover, the significant differences in overall salivary microbiota structure between DGF and IGF patients disappeared upon long-term follow-up. This is the first study to investigate the dynamic changes in salivary microbiota in DGFs. Our findings suggested that salivary microbiota was able to predict DGF in the early stages after kidney transplantation, which might help the perioperative clinical management and early-stage intervention of kidney transplant recipients. KEY POINTS: • Salivary microbiota on the first day after KT could predict DGF. • Alterations in salivary taxa after KT are related to recovery of renal function.

HDAC6 inhibition: a significant potential regulator and therapeutic option to translate into clinical practice in renal transplantation

Histone deacetylase 6 (HDAC6), an almost exclusively cytoplasmic enzyme, plays an essential role in many biological processes and exerts its deacetylation-dependent/independent effects on a variety of target molecules, which has contributed to the flourishing growth of relatively isoform-specific enzyme inhibitors. Renal transplantation (RT) is one of the alternatively preferred treatments and the most cost-effective treatment approaches for the great majority of patients with end-stage renal disease (ESRD). HDAC6 expression and activity have recently been shown to be increased in kidney disease in a number of studies. To date, a substantial amount of validated studies has identified HDAC6 as a pivotal modulator of innate and adaptive immunity, and HDAC6 inhibitors (HDAC6i) are being developed and investigated for use in arrays of immune-related diseases, making HDAC6i a promising therapeutic candidate for the management of a variety of renal diseases. Based on accumulating evidence, HDAC6i markedly open up new avenues for therapeutic intervention to protect against oxidative stress-induced damage, tip the balance in favor of the generation of tolerance-related immune cells, and attenuate fibrosis by inhibiting multiple activations of cell profibrotic signaling pathways. Taken together, we have a point of view that targeting HDAC6 may be a novel approach for the therapeutic strategy of RT-related complications, including consequences of ischemia-reperfusion injury, induction of immune tolerance in transplantation, equilibrium of rejection, and improvement of chronic renal graft interstitial fibrosis after transplantation in patients. Herein, we will elaborate on the unique function of HDAC6, which focuses on therapeutical mechanism of action related to immunological events with a general account of the tantalizing potential to the clinic.

Improved Organ Utilization and Better Transplant Outcomes With In Situ Normothermic Regional Perfusion in Controlled Donation After Circulatory Death

BACKGROUND

. We evaluated whether the use of normothermic regional perfusion (NRP) was associated with increased organ recovery and improved transplant outcomes from controlled donation after circulatory death (cDCD).

METHODS

. This is a retrospective analysis of UK adult cDCD donors' where at least 1 abdominal organ was accepted for transplantation between January 1, 2011, and December 31, 2019.

RESULTS

. A mean of 3.3 organs was transplanted when NRP was used compared with 2.6 organs per donor when NRP was not used. When adjusting for organ-specific donor risk profiles, the use of NRP increased the odds of all abdominal organs being transplanted by 3-fold for liver ( P < 0.0001; 95% confidence interval [CI], 2.20-4.29), 1.5-fold for kidney ( P = 0.12; 95% CI, 0.87-2.58), and 1.6-fold for pancreas ( P = 0.0611; 95% CI, 0.98-2.64). Twelve-mo liver transplant survival was superior for recipients of a cDCD NRP graft with a 51% lower risk-adjusted hazard of transplant failure (HR = 0.494). In risk-adjusted analyses, NRP kidneys had a 35% lower chance of developing delayed graft function than non-NRP kidneys (odds ratio, 0.65; 95% CI, 0.465-0.901)' and the expected 12-mo estimated glomerular filtration rate was 6.3 mL/min/1.73 m 2 better if abdominal NRP was used ( P < 0.0001).

CONCLUSIONS

. The use of NRP during DCD organ recovery leads to increased organ utilization and improved transplant outcomes compared with conventional organ recovery.

[Association between controlled circulatory death donor waitlisting and waiting time before kidney transplantation in a French center]

INTRODUCTION

Transplantation from controlled donation after circulatory determination of death (cDCD) is a new practice in France. An additional specific consent is required for registration on the cDCD waiting list. The aim of this study is to evaluate the impact of cDCD acceptance on the waiting time for the registered patients on the transplant list.

METHODS

Patients registered on the kidney transplant waiting list for a Death Brain Donor (DBD) kidney transplant between 2018 and 2019 in our center were included. Patients who were candidates for a second kidney transplant or who had already received an organ transplant were not included. The cDCD waiting list registration was authorized by a signed consent of the patient on the day of DBD registration. The primary endpoint was time to renal transplantation.

RESULTS

Of the 315 patients eligible for a cDCD graft at transplant list registration, 152 were registered on the cDCD waiting list. Time to transplantation for these patients was multiplied by 1.42 (95%CI 1.07-1.87) compared with patients not registered for a cDCD graft. The time to transplantation was 2.59 months (95%CI 0.49-4.69) shorter for a 2-year follow-up for cDCD-listed patients. This represents one additional transplant at 6 months for every seven registered patients.

CONCLUSION

cDCD waiting list registration reduced the time to kidney transplantation in France.

"A Delicate balance"-Perceptions and Experiences of ICU Physicians and Nurses Regarding Controlled Donation After Circulatory Death. A Qualitative Study

Controlled donation after circulatory death (cDCD) is considered by many as a potential response to the scarcity of donor organs. However, healthcare professionals may feel uncomfortable as end-of-life care and organ donation overlap in cDCD, creating a potential barrier to its development. The aim of this qualitative study was to gain insight on the perceptions and experiences of intensive care units (ICU) physicians and nurses regarding cDCD. We used thematic analysis of in-depth semi-structured interviews and 6-month field observation in a large teaching hospital. 17 staff members (8 physicians and 9 nurses) participated in the study. Analysis showed a gap between ethical principles and routine clinical practice, with a delicate balance between end-of-life care and organ donation. This tension arises at three critical moments: during the decision-making process leading to the withdrawal of life-sustaining treatments (LST), during the period between the decision to withdraw LST and its actual implementation, and during the dying and death process. Our findings shed light on the strategies developed by healthcare professionals to solve these ethical tensions and to cope with the emotional ambiguities. cDCD implementation in routine practice requires a shared understanding of the tradeoff between end-of-life care and organ donation within ICU.

Critical pathways for controlled donation after circulatory death in France

INTRODUCTION

In 2015, France authorised controlled donation after circulatory death (cDCD) according to a nationally approved protocol. The aim of this study is to provide an overview from the perspective of critical care specialists of cDCD. The primary objective is to assess how the organ donation procedure affects the withdrawal of life-sustaining therapies (WLST) process. The secondary objective is to assess the impact of cDCD donors' diagnoses on the whole process.

MATERIAL AND METHODS

This 2015-2019 prospective observational multicentre study evaluated the WLST process in all potential cDCD donors identified nationwide, comparing 2 different sets of subgroups: 1- those whose WLST began after organ donation was ruled out vs. while it was still under consideration; 2- those with a main diagnosis of post-anoxic brain injury (PABI) vs. primary brain injury (PBI) at the time of the WLST decision.

RESULTS

The study analysed 908 potential cDCD donors. Organ donation remained under consideration at WLST initiation for 54.5% of them with longer intervals between their WLST decision and its initiation (2 [1-4] vs. 1 [1-2] days, P < 0.01). Overall, 60% had post-anoxic brain injury. Time from ICU admission to WLST decision was longer for primary brain injury donors (10 [4-21] vs. 6 [4-9] days, P < 0.01). Median time to death (agonal phase) was 15 [15-20] minutes.

CONCLUSIONS

French cDCD donors are mostly related to post-anoxic brain injury. The organ donation process does not accelerate WLST decision but increases the interval between the WLST decision and its initiation.

Novel Organ Perfusion and Preservation Strategies in Controlled Donation After Circulatory Death in Pancreas and Kidney Transplantation

BACKGROUND

Kidney and pancreatic transplants from controlled donation after circulatory death donors are vulnerable to ischemia-reperfusion injuries. In this context of transplant shortage, there is a need to optimize the function of these transplants and to develop novel perfusion and preservation strategies in controlled donation after circulatory death in kidney and pancreatic transplants.

IN SITU PERFUSION AND PRESERVATION STRATEGIES

In situ regional normothermic perfusion improves the outcome of kidney transplants from controlled donation after circulatory death and provides equivalent results for the kidney from brain-dead donors. In situ regional normothermic perfusion is under investigation for pancreatic transplants.

EX SITU PERFUSION AND PRESERVATION STRATEGIES

Perfusion on hypothermic machine perfusion is highly recommended for the kidney from controlled donation after cardiac death. Hypothermic oxygenated perfusion machine decreases the rate of graft rejection and graft failure in kidney transplantation. Ex situ normothermic perfusion is an easy way to assess renal function. In the future, kidney transplants could benefit from drug therapy during ex situ normothermic perfusion. In pancreas transplantation, hypothermic machine perfusion and ex situ normothermic perfusion present encouraging results in preclinical studies.