ESOT Congress Daily Recap
Monday 30 June 2025
A Changing Climate: Challenges for Society, Healthcare Systems, and Transplantation - Opening Plenary Highlights
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Scientific Programme Highlights: New study provides breakthrough in pig-to-human kidney transplantation
A pioneering study, presented today at the ESOT Congress, has provided unprecedented insights into the immune response following pig-to-human kidney xenotransplantation. The findings mark a significant step forward in overcoming the biggest challenge in xenotransplantation: rejection by the human immune system.
Using cutting-edge spatial molecular imaging, the international research team (Paris Institute for Transplantation and Organ Regeneration & NYU Langone Transplant Institute) mapped how human immune cells interact with pig kidney tissue in transplanted organs, revealing critical early markers of rejection and potential intervention strategies.
Human immune cells were found in every part of the pig kidney's filtering system after the transplant. The researchers observed early molecular signs of antibody-mediated rejection as soon as Day 10 and peaking at Day 33, reinforcing previous findings that rejection begins rapidly but progresses over time. By tracking these immune responses for up to 61 days, the team identified a crucial window for targeted therapeutic intervention.
The study’s innovative approach used a bioinformatic pipeline to distinguish human immune cells from pig structural cells, allowing for precise mapping of immune infiltration patterns. Notably, macrophages and myeloid cells were the most prevalent immune cell types across all time points, further confirming their role as key mediators in xenograft rejection. When targeted therapeutic interventions were introduced, immune-mediated signs of rejection were successfully weakened. Combined with novel spatial insights into how immune cells interact with pig kidney tissue, this marks a major breakthrough — paving the way for more refined anti-rejection strategies. These advances come at a pivotal time as the first US-based clinical trials of pig kidney transplantation into living human recipients begin in 2025.
“Our study provides the most detailed molecular map to date of how the human immune system engages with a transplanted pig kidney,” explained Dr. Goutaudier. “By pinpointing specific immune cell behaviours and gene expressions, we can refine anti-rejection treatments and improve transplant viability.”
With xenotransplantation poised to address the global organ shortage crisis, these findings bring researchers one step closer to making genetically modified pig kidneys a viable long-term solution.
Stronger Together PRO Award
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Scientific Programme Highlights: Deceased-donor-initiated chains sustain kidney paired donation in Italy
Leonardo Da Vinci Award Nominee: Cristina Silvestre
The pioneering DEC-K (DECeased-donor initiated Kidney exchange) programme leverages deceased donors to trigger transplant chains involving immunologically incompatible living-donor pairs. From March 2018 to December 2024, 30 chains were launched across 15 transplant centres, resulting in 79 transplants; 52 from living donors and 27 from deceased donors were returned to the regional transplant waiting list of the initiating donor’s region, preserving geographic fairness at chain conclusion.
Most chains involved two to three donor–recipient dyads and were prompted by ABO (blood type) incompatibility (n=25), HLA (immune system) sensitisation (n=19), or both (n=6). Chains had an average duration of 98.5 days, reflecting the coordination needed to complete multi-centre exchanges. Despite this complexity, the programme maintained a high completion rate.
Notably, 93.6% of chains completed successfully. Reasons for early termination in three cases included clinical or psychological issues. Importantly, no serious complications occurred in living donors, and only four graft losses were recorded: two vascular thromboses, one rejection, and one primary non-function.
At 6-months post-transplant, serum creatinine levels were comparable between living and deceased donor recipients (1.3 vs. 1.4 mg/dL; p=0.24), and one-year patient survival reached 98.7%.
This study confirms the feasibility and impact of deceased-donor-initiated chains in expanding transplant access and supporting equity-driven organ allocation, particularly in settings where altruistic, non-directed donors are scarce.
Scientific Programme Highlights: Pre-donation cardiac arrest is associated with modest graft survival benefit in liver transplantation
Leonardo Da Vinci Award Nominee: Dharesh Raj Amarnath
Analysis of the United Network for Organ Sharing (UNOS) registry suggests that livers from donors with pre-donation cardiac arrest may confer a modest survival advantage, supporting their safe use in clinical liver transplantation.
Ischemic preconditioning through pre-donation cardiac arrest (PDCA) may render donor livers more resilient to ischemia-reperfusion injury. Analysing 74,592 adult liver transplant procedures from the UNOS registry (2010–2023), investigators identified PDCA in 43.7% of donors. After adjusting for donor and recipient factors, PDCA was associated with modestly improved graft survival (adjusted hazard ratio [aHR] 0.914; 95% CI, 0.851–0.982; p=0.012), with greater benefit observed in donation after circulatory death (DCD) donors and those with elevated alanine aminotransferase (ALT).
The effect was more evident in specific donor subgroups, with survival benefits concentrated among DCD donors, those with moderately elevated ALT, shorter admission-to-donation intervals, and older donor age. A dose–response trend also emerged: each doubling of PDCA duration conferred additional graft survival benefit (aHR 0.953; 95% CI, 0.917–0.991; p=0.018).
No increase in early allograft dysfunction was observed, and similar associations were seen across secondary outcomes, reinforcing the robustness of the findings.
These results represent the largest real-world demonstration of ischemic preconditioning in liver transplantation and support the inclusion of PDCA livers in clinical practice, potentially expanding the donor pool by reducing unnecessary discards.
Scientific Programme Highlights: Ex vivo hypothermic perfusion preserves paediatric hearts for up to 8 hours
Leonardo Da Vinci Award Nominee: Kristina Andrijauskaite
A novel portable device demonstrated safe, effective preservation of paediatric-sized donor hearts with strong myocardial function and transplant success in preclinical models.
The VP.S ENCORE® PEDSTM device represents a critical innovation in paediatric donor heart preservation, employing a bespoke hypothermic perfusion system tailored to meet the metabolic needs of small hearts. In this preclinical study, six porcine hearts approximating infant and child size were perfused at 7.8 ± 1.5 °C under a controlled pressure of 11 ± 1.4 mmHg, achieving mean flow rates of 22 ± 14 mL/min for up to 8 hours. No edema was observed during preservation.
Metabolic assessment revealed low lactate levels (<3 mmol/L) throughout perfusion, consistent with sustained aerobic metabolism and limited ischemic injury. Endothelial integrity assays confirmed preservation of the vascular lining, while Langendorff re-perfusion testing showed strong left ventricular contractility (dP/dT >2,000 mmHg/s), indicating preserved myocardial function.
Two heterotopic transplants of preserved hearts were successfully completed in matched porcine recipients, showing 100% survival, normal metabolic profiles, and stable cardiac activity at the time of implantation. Behavioral assessments in recipient animals were within normal range through postoperative day 7, with no signs of rejection.
By safely extending preservation time beyond the 4–6 hour limit of cold storage, this device could transform transplant logistics, expanding access across wider geographic regions and reducing time pressures during surgical coordination. Future studies will assess long-term outcomes, immunologic responses, and support translation to clinical trials in paediatric patients.
Scientific Programme Highlights: T-cell regulatory loss precedes emergence of de novo donor-specific antibodies
Leonardo Da Vinci Award Nominee: Sumoyee Basu
A new study reveals that dysregulated alloreactive T-cell responses can be detected months before the emergence of de novo donor-specific antibodies (dnDSA) in kidney transplant recipients.
To explore early immune events leading to dnDSA, researchers conducted longitudinal analyses on peripheral blood samples from 52 initially DSA-negative patients in the OuTSMART trial. Using FluoroSpot assays, they measured IFN-γ and IL-17 production from CD4⁺ T cells following stimulation with donor and control HLA proteins, with and without depletion of regulatory cell subsets (CD19⁺ B cells and CD25^hi Tregs).
Antigen-specific IFN-γ responses (ASR) were detectable in 67.9% of assays (95/140), including in samples collected up to 32 months before dnDSA onset. From 4-months prior to dnDSA detection, unregulated IFN-γ responses to donor antigens became more prevalent, while control responses remained predominantly regulated. Furthermore, 28% of DSA samples (n=74) had unregulated IFN-γ responses, compared with 21% of controls (n=66), while regulated responses were twice as frequent in controls. No similar trend was observed for IL-17. Flow cytometry profiling suggested changes in regulatory immune subsets during this pre-sensitisation window.
These findings offer the first clinical systematic evidence of a quantifiable immune shift preceding dnDSA, identifying a potential window for early risk stratification and immune intervention to preserve long-term graft function.
Thank you to our partners
ESOT would like to thank its partners for supporting the ESOT Congress and for working together to improve outcomes for patients with terminal organ disease by means of transplantation, organ regeneration and substitution.
