OBJECTIVE: The shortage of donor liver hinders the development of liver transplantation. This study aimed to clarify the poor outcomes of functionally marginal liver grafts (FMLs) and provide evidence for the improvement of ischemia-free liver transplantation (IFLT) after FML transplantation.
METHODS: Propensity score matching was used to control for confounding factors. The outcomes of the control group and FML group were compared to demonstrate the negative impact of FMLs on liver transplantation patients. We compared the clinical improvements of the different surgical types. To elucidate the underlying mechanism, we conducted bioinformatic analysis based on transcriptome and single-cell profiles.
RESULTS: FMLs had a significantly greater hazard ratio (HR: 1.969, P=0.018) than did other marginal livers. A worse 90-day survival (Mortality: 12.3% vs. 5.0%, P=0.007) was observed in patients who underwent FML transplantation. Patients who received FMLs had a significant improvement in overall survival after IFLT (Mortality: 10.4% vs 31.3%, P=0.006). Pyroptosis and inflammation were inhibited in patients who underwent IFLT. The infiltration of natural killer cells was lower in liver grafts from these patients. Bulk transcriptome profiles revealed a positive relationship between IL-32 and Caspase 1 (R=0.73, P=0.01) and between IL-32 and Gasdermin D (R=0.84, P=0.0012).
CONCLUSIONS: FML is a more important negative prognostic parameter than other marginal liver parameters. IFLT might ameliorate liver injury in FMLs by inhibiting the infiltration of NK cells, consequently leading to the abortion of IL-32, which drives pyroptosis in monocytes and macrophages.

UNASSIGNED: The magnitude of potential benefits that hypothermic oxygenated perfusion (HOPE) may provide for liver transplantation (LT) patients compared to static cold storage (SCS) remains uncertain. In this systematic review and meta-analysis, we aimed to investigate the therapeutic effect that HOPE can offer LT recipients relative to SCS by synthesizing available evidence.
UNASSIGNED: A literature search was conducted in Embase, Medline, Web of Science, and the Cochrane database up to 1 June, 2023. The included studies were pooled for meta-analysis to synthesize their findings. Subgroup analysis was performed to investigate potential differences between HOPE and SCS for specific subgroups.
UNASSIGNED: A total of 11 studies comprising 1765 patients were included. Compared with SCS, HOPE was associated with a significant reduction in the incidence of early allograft dysfunction (EAD) (OR: 0.36, 95% CI: 0.26-0.50), as well as a noteworthy decrease in graft loss rate within one year (OR: 0.57, 95% CI: 0.33-0.97) and a lower occurrence of Clavien-Dindo grade IIIa or higher complications (OR: 0.62, 95% CI: 0.43-0.89). Subgroup analysis revealed that HOPE significantly reduced the one-year mortality rate, any biliary complications incidence, and acute rejection of transplanted liver rate in patients who received organs from donation after cardiac death (DCD).
UNASSIGNED: HOPE has demonstrated efficacy in reducing the incidence of EAD after LT and shows some potential in diminishing postoperative complications such as biliary complications and acute rejection. This ultimately leads to improved patient prognosis, particularly among those receiving DCD grafts.

OBJECTIVE: Ischemia and hypoxia are the main factors limiting limb replantation and transplantation. Static cold storage (SCS), a common preservation method for tissues and organs, can only prolong limb ischemia time to 4 - 6 h. The normothermic machine perfusion (NMP) is a promising method for the preservation of tissues and organs, which can extend the preservation time in vitro by providing continuous oxygen and nutrients. This study aimed to evaluate the difference in the efficacy of the 2 limb preservation methods.
METHODS: The 6 forelimbs from beagle dogs were divided into 2 groups. In the SCS group (n = 3), the limbs were preserved in a sterile refrigerator at 4 °C for 24 h, and in the NMP group (n = 3), the perfusate prepared with autologous blood was used for the oxygenated machine perfusion at physiological temperature for 24 h, and the solution was changed every 6 h. The effects of limb storage were evaluated by weight gain, perfusate biochemical analysis, enzyme-linked immunosorbent assay, and histological analysis. All statistical analyses and graphs were performed using GraphPad Prism 9.0 one-way or two-way analysis of variance. The p value of less than 0.05 was considered to indicate statistical significance.
RESULTS: In the NMP group, the weight gained percentage was 11.72% ± 4.06%; the hypoxia-inducible factor-1α contents showed no significant changes; the shape of muscle fibers was normal; the gap between muscle fibers slightly increased, showing the intercellular distance of (30.19 ± 2.83) μm; and the vascular α-smooth muscle actin (α-SMA) contents were lower than those in the normal blood vessels. The creatine kinase level in the perfusate of the NMP group increased from the beginning of perfusion, decreased after each perfusate change, and remained stable at the end of perfusion showing a peak level of 4097.6 U/L. The lactate dehydrogenase level of the NMP group increased near the end of perfusion and reached the peak level of 374.4 U/L. In the SCS group, the percentage of weight gain was 0.18% ± 0.10%, and the contents of hypoxia-inducible factor-1α increased gradually and reached the maximum level of (164.85 ± 20.75) pg/mL at the end of the experiment. The muscle fibers lost their normal shape and the gap between muscle fibers increased, showing an intercellular distance of (41.66 ± 5.38) μm. The contents of vascular α-SMA were much lower in the SCS group as compared to normal blood vessels.
CONCLUSIONS: NMP caused lesser muscle damage and contained more vascular α-SMA as compared to SCS. This study demonstrated that NMP of the amputated limb with perfusate solution based on autologous blood could maintain the physiological activities of the limb for at least 24 h.

Static cold storage is the cheapest and easiest method and current gold standard to store and preserve donor organs. This study aimed to compare the preservative capacity of gluconate-lactobionate-dextran (Unisol) solutions to histidine-tryptophan-ketoglutarate (HTK) solution. Murine syngeneic heterotopic heart transplantations (Balb/c-Balb/c) were carried out after 18 h of static cold storage. Cardiac grafts were either flushed and stored with Unisol-based solutions with high-(UHK) and low-potassium (ULK) ± glutathione, or HTK. Cardiac grafts were assessed for rebeating and functionality, histomorphologic alterations, and cytokine expression. Unisol-based solutions demonstrated a faster rebeating time (UHK 56 s, UHK + Glut 44 s, ULK 45 s, ULK + Glut 47 s) compared to HTK (119.5 s) along with a better contractility early after reperfusion and at the endpoint on POD 3. Ischemic injury led to a significantly increased leukocyte recruitment, with similar degrees of tissue damage and inflammatory infiltrate in all groups, yet the number of apoptotic cells tended to be lower in ULK compared to HTK. In UHK- and ULK-treated animals, a trend toward decreased expression of proinflammatory markers was seen when compared to HTK. Unisol-based solutions showed an improved preservative capacity compared with the gold standard HTK early after cardiac transplantation. Supplemented glutathione did not further improve tissue-protective properties.

Background: Machine perfusion (MP) and static cold storage (CS) are two prevalent methods for liver allograft preservation. However, the preferred method remains controversial. Aim: To conduct a meta-analysis on the impact of MP preservation on liver transplant outcome. Methods: PubMed, EMBASE, and Cochrane Library databases were systematically searched to identify relevant trials comparing the efficacy of MP vs. CS. Odds ratios (OR) and fixed-effects models were calculated to compare the pooled data. Results: Ten prospective cohort studies and two randomized controlled trials (RCTs) were included (MP livers vs. CS livers = 315:489). Machine perfusion demonstrated superior outcomes in posttransplantation aspartate aminotransferase levels compared to CS (P < 0.05). The overall incidence of early allograft dysfunction (EAD) was significantly reduced with MP preservation than CS [OR = 0.46; 95% confidence interval (CI) = 0.31-0.67; P < 0.0001]. The incidence of total biliary complications (OR = 0.53; 95% CI = 0.34-0.83; P = 0.006) and that of ischemic cholangiopathy (OR = 0.39; 95% CI = 0.18-0.85; P = 0.02) were significantly lower in recipients with MP preservation compared with CS preservation. Hypothermic machine perfusion (HMP) but not normothermic machine perfusion (NMP) was found to significantly protect grafts from total biliary complications and ischemic cholangiopathy (P < 0.05). However, no significant differences could be detected utilizing either HMP or NMP in primary nonfunction, hepatic artery thrombosis, postreperfusion syndrome, 1-year patient survival, or 1-year graft survival (P > 0.05). Conclusions: Machine perfusion is superior to CS on improving short-term outcomes for human liver transplantation, with a less clear effect in the longer term. Hypothermic machine perfusion but not NMP conducted significantly protective effects on EAD and biliary complications. Further RCTs are warranted to confirm MP\'s superiority and applications.

OBJECTIVE: This study was performed to evaluate the impact and underlying mechanisms of hypothermic machine perfusion (HMP) on half-size liver graft regeneration.
METHODS: Forty rats were randomly assigned to five groups: two in vitro groups (static cold storage [SCS] and HMP) and three in vivo groups (orthotopic liver transplantation, SCS, and HMP). Perfusates and plasma samples were collected for analysis of hepatic enzymes. Liver tissue was obtained for evaluation of histology, immunohistochemistry (Ki67 and proliferating cell nuclear antigen [PCNA]), and the regeneration rate. Cell cycle genes were analyzed by quantitative real-time polymerase chain reaction, and cyclin D1 and cyclin E1 were semiquantified by western blot.
RESULTS: HMP improved histopathological outcomes and decreased hepatic enzyme release. The expression of Ki67 and PCNA demonstrated a greater proliferation activity in the HMP than SCS group, and the expression of almost all cell cycle genes was elevated following HMP. Western blot results showed higher protein levels of cyclin D1 and cyclin E1 in the HMP than SCS group.
CONCLUSIONS: Our findings suggest for the first time that half-size liver graft protection by HMP involves recovery of graft regeneration.

Static cold storage (SCS) and hypothermic machine perfusion (HMP) are two primary options for renal allograft preservation. Compared with SCS, HMP decreased the incidence of delayed graft function (DGF) and protected graft function. However, more evidence is still needed to prove the advantages of the HMP. In this study, the outcomes of kidney grafts from the two preservation methods were compared by conducting a systematic review and meta-analysis. Randomized controlled trials (RCTs) comparing the effect of hypothermic machine perfusion and static cold storage in deceased donor kidney transplantation were identified through searches of the MEDLINE, EMBASE, and Cochrane databases between January 1, 1980 and December 30, 2017. The primary endpoints were delayed graft function and graft survival. Secondary endpoints included primary non-function (PNF), graft renal function, duration of DGF, acute rejection, postoperative hospital stay and patient survival. Summary effects were calculated as risk ratio (RR) with 95% confidence interval (CI) or mean difference (MD) with 95% confidence intervals (CI). A total of 13 RCTs were included, including 2048 kidney transplant recipients. The results indicated that compared with SCS, HMP decreased the incidence of DGF (RR 0.78, 95% CI 0.69-0.87, P < 0.0001), and improved the graft survival at 3 years (RR 1.06, 95% CI 1.02-1.11, P = 0.009). There was no significant difference in other endpoints. HMP might be a more desirable method of preservation for kidney grafts. The long-term outcomes of kidney allografts stored by hypothermic machine perfusion still need to be further investigated.

OBJECTIVE: To optimize the perfusates used for hypothermic machine perfusion (HMP).
METHODS: Sprague-Dawley rats were assigned randomly to three groups (n = 12 per group) that received either saline, University of Wisconsin cold-storage solution (UW) or histidine-tryptophan-ketoglutarate solution (HTK) as the perfusate. Each group was divided into two subgroups: static cold storage (SCS) and HMP (n = 6 per subgroup). The liver graft was retrieved according to the method described by Kamada. For the SCS group, the graft was directly placed into cold perfusate (0-4 °C) for 6 h after liver isolation while the portal vein of the graft was connected to the perfusion machine for the HMP group. Then the perfusates were collected at different time points for analysis of aspartate aminotransferase (AST), alanine transaminase (ALT) and lactate dehydrogenase (LDH) levels. Liver tissues were obtained for evaluation of histology, dry/wet weight (D/W) ratio, and malondialdehyde (MDA) and adenosine-triphosphate (ATP) levels. The portal vein pressure and velocity were monitored in real time in all HMP subgroups.
RESULTS: Comparison of HMP and SCS: Regardless of the perfusate, HMP improved the architecture of donor graft in reducing the congestion around sinusoids and central vein and maintaining sinusoid lining in morphology; HMP improved liver function in terms of ALT, AST and LDH, especially during the 3-6 h period (SCS vs HMP using saline: ALT3, 225.00 ± 105.62 vs 49.50 ± 18.50, P = 0.047; LDH3, 1362.17 ± 563.30 vs 325.75 ± 147.43, P = 0.041; UW: LDH6, 2880.14 ± 948.46 vs 2135.00 ± 174.27, P = 0.049; HTK, AST6, 307.50 ± 52.95 vs 185.20 ± 20.46, P = 0.041); HMP decreased MDA level (saline, 2.79 ± 0.30 vs 1.09 ± 0.09, P = 0.008; UW, 3.01 ± 0.77 vs 1.23 ± 0.68, P = 0.005; HTK, 3.30 ± 0.52 vs 1.56 ± 0.22, P = 0.006). Comparison among HMP subgroups: HTK showed less portal vein resistance than UW and saline (vs saline, 3.41 ± 0.49 vs 5.00 ± 0.38, P < 0.001; vs UW, 3.41 ± 0.49 vs 4.52 ± 0.63, P = 0.007); UW reduced edema most efficiently (vs saline, 0.68 ± 0.02 vs 0.79 ± 0.05, P = 0.013), while HTK maintained ATP levels best (vs saline, 622.60 ± 29.11 vs 327.43 ± 44.66, P < 0.001; vs UW, 622.60 ± 29.11 vs 301.80 ± 37.68, P < 0.001).
CONCLUSIONS: HMP is superior to SCS in maintaining both architecture and function of liver grafts. Further, HTK was found to be the optimal perfusate for HMP.