Machine perfusion technologies have redefined the landscape of organ preservation by enabling not just static cold storage, but graft optimization and assessment with the opportunity for additional therapeutic interventions. Preservation solutions, traditionally developed for static cold storage, are now being adapted for use in dynamic perfusion platforms. The optimal composition for machine perfusion remains unclear as we shift to creating biologically intelligent platforms tailored to mitigate ischemia–reperfusion injury. This review presents a mechanistic framework for understanding organ preservation through the lens of shared vulnerabilities, particularly: mitochondrial dysfunction, endothelial barrier breakdown, and the activation of inflammatory cascades. We discuss the evolution of classical preservation solutions, the rationale for redox-targeted and endothelial-stabilizing additives, and the promise of modular approaches adaptable to both static cold storage and machine perfusion. By integrating recent preclinical insights, systems biology, and emerging clinical trials, we outline the path toward unified, precision-preservation strategies capable of expanding the donor pool and improving transplant outcomes.

Ex situ machine perfusion has emerged as a pivotal technique for organ preservation and pre-transplant viability assessment, where the real-time monitoring of mitochondrial biomarkers—flavin mononucleotide (FMN) and nicotinamide adenine dinucleotide (NADH)—could significantly mitigate ischemia-reperfusion injury risks. This study develops a non-invasive optical method combining fluorescence and UV-visible spectrophotometry to quantify FMN and NADH in hypothermic oxygenated perfusion media. Calibration curves revealed linear responses for both biomarkers in absorption and fluorescence (FMN: λ_ex = 445 nm, λ_em = 530–540 nm; NADH: λ_ex = 340 nm, λ_em = 465 nm) at concentrations < 100 μg mL⁻¹. However, NADH exhibited nonlinear fluorescence above 100 μg mL⁻¹, requiring shifted excitation to 365 nm for reliable detection. Spectroscopic analysis further demonstrated how perfusion solution composition alters FMN/NADH fluorescence properties, with consistent reproducibility across media. The method’s robustness was validated through comparative studies in clinically relevant solutions, proposing a strategy for precise biomarker quantification without invasive sampling. These findings establish a foundation for real-time, optical biosensor development to enhance organ perfusion monitoring. By bridging spectroscopic principles with clinical needs, this work advances translational sensor technologies for transplant medicine, offering a template for future device integration.

Background: Uterus transplantation (UTx) is an emerging treatment for absolute uterine factor infertility. However, the use of deceased donors is limited, and donation after circulatory death (DCD) has not yet been utilized. Ischemic injury remains a major barrier, particularly compared with living donor procedures. Hypothermic oxygenated perfusion (HOPE), which has shown protective effects in heart, liver, and kidney transplantation, may offer similar benefits for uterine grafts. Methods: We report the first series applying HOPE to human uteri to improve preservation and enable metabolic injury assessment during perfusion. Six uteri (3 DBD, 3 DCD; median donor age 53 years) underwent 8 h of HOPE following procurement, while paired tissue controls were preserved using static cold storage (SCS). Perfusion was delivered using a pressure-controlled system (15 mmHg, 10 ± 1 °C, VitaSmart^®). Perfusate and tissue samples were analyzed for mitochondrial injury, inflammation, and transcriptional responses. Results: HOPE maintained stable flows (70–150 mL/min), delivered high oxygen levels (pO₂ ≈ 1000 hPa), and increased tissue ATP levels. Stratification based on perfusate flavin mononucleotide (FMN) release identified grafts with greater Complex I/II injury. HOPE was associated with lower levels of mitochondrial injury markers and inflammatory signals, preserved tissue architecture, and promoted gene expression patterns consistent with metabolic recovery compared with paired SCS tissue controls. Conclusions: These findings suggest that HOPE may serve as a preservation approach that enables metabolic and ischemic injury assessment and may facilitate broader use of deceased donor uteri for transplantation.

Background/Objectives: The use of extended-criteria donors (ECDs) is rapidly increasing, with higher risks for impaired outcomes after liver transplantation (LT). Normothermic machine perfusion (NMP) can enhance graft viability assessment, though lactate clearance as a viability marker lacks consensus in clinical practice. Methods: This study analyzed 213 adult liver transplants using NMP from October 2022 to January 2024. Perfusate lactate levels were measured with an Epoc^® reader and five lactate-based viability criteria were evaluated for predicting post-LT outcomes. Results: All livers cleared lactate at 6 h of NMP (median 0.51 mmol/L). However, 33 livers failed at least one lactate viability criterion. Thirteen livers (6.1%) were discarded based on traditional criteria, but discard rates would have been higher using Groningen (14.6%) or Brisbane (11.2%) criteria for lactate. Outcomes for the recipients of livers that failed the lactate criteria were comparable to those of recipients with livers meeting all criteria, including biliary complications (p = 0.63), graft survival (>0.99), and 6-month CCI (p = 0.89). ROC analysis revealed poor predictive value for graft survival for lactate clearance criteria (AUC 0.50), while lactate was outperformed by MEAF score (AUC 0.67). Conclusions: Lactate clearance alone does not predict outcomes, highlighting the need for further validation of alternative viability.

Background/Objectives: Hypothermic oxygenated perfusion (HOPE) improves graft preservation in whole liver transplantation, yet evidence supporting its use in split grafts for pediatric transplantation remains limited. Mitochondrial injury assessed during HOPE through spectroscopic measurement of flavin mononucleotide (FMN) has been associated with graft function in whole-organ transplantation. Here, we evaluate a human liver assessment pathway integrating mitochondrial viability testing with ex situ liver splitting during HOPE. Methods: Following standard procurement and transport, twelve discarded extended criteria human donor livers were evaluated for split feasibility and underwent HOPE (VitaSmart^®). Donors were between 40 and 72 years with a BMI of 23.4–42.7 kg/m² and 4–22 h of cold storage prior to HOPE. After two hours of portal-venous HOPE treatment, different split procedures were performed. Perfusates and tissues were analyzed for mitochondrial injury and inflammatory responses. Results: Four grafts met previously reported FMN thresholds for transplant suitability in whole-graft HOPE studies (FMN ≤ 0.02 μg/mL at 60 min). Livers with low FMN release demonstrated lower Complex I and II injury, greater ATP recovery, and reduced inflammatory signaling during HOPE. Conclusions: These findings indicate that mitochondrial injury during HOPE can be monitored during ex situ splitting and suggest that FMN-guided metabolic assessment may support graft evaluation within split liver transplantation pathways for pediatric recipients.