Portable hypothermic oxygenated machine perfusion for organ preservation in liver transplantation: A randomized, open-label, clinical trial.

BACKGROUND AND AIMS: In liver transplantation, cold preservation induces ischemia, resulting in significant reperfusion injury. Hypothermic oxygenated machine perfusion (HMP-O 2 ) has shown benefits compared to static cold storage (SCS) by limiting ischemia-reperfusion injury. This study reports outcomes using a novel portable HMP-O 2 device in the first US randomized control trial. APPROACH AND RESULTS: The PILOT trial (NCT03484455) was a multicenter, randomized, open-label, noninferiority trial, with participants randomized to HMP-O 2 or SCS. HMP-O 2 livers were preserved using the Lifeport Liver Transporter and Vasosol perfusion solution. The primary outcome was early allograft dysfunction. Noninferiority margin was 7.5%. From April 3, 2019, to July 12, 2022, 179 patients were randomized to HMP-O 2 (n=90) or SCS (n=89). The per-protocol cohort included 63 HMP-O 2 and 73 SCS. Early allograft dysfunction occurred in 11.1% HMP-O 2 (N=7) and 16.4% SCS (N=12). The risk difference between HMP-O 2 and SCS was -5.33% (one-sided 95% upper confidence limit of 5.81%), establishing noninferiority. The risk of graft failure as predicted by Liver Graft Assessment Following Transplant score at seven days (L-GrAFT 7 ) was lower with HMP-O 2 [median (IQR) 3.4% (2.4-6.5) vs. 4.5% (2.9-9.4), p =0.024]. Primary nonfunction occurred in 2.2% of all SCS (n=3, p =0.10). Biliary strictures occurred in 16.4% SCS (n=12) and 6.3% (n=4) HMP-O 2 ( p =0.18). Nonanastomotic biliary strictures occurred only in SCS (n=4). CONCLUSIONS: HMP-O 2 demonstrates safety and noninferior efficacy for liver graft preservation in comparison to SCS. Early allograft failure by L-GrAFT 7 was lower in HMP-O 2 , suggesting improved early clinical function. Recipients of HMP-O 2 livers also demonstrated a lower incidence of primary nonfunction and biliary strictures, although this difference did not reach significance.

CITED4 gene therapy protects against maladaptive cardiac remodeling after ischemia/reperfusion injury in mice.

Cardiac signaling pathways functionally important in the heart's response to exercise often protect the heart against pathological stress, potentially providing novel therapeutic targets. However, it is important to determine which of these pathways can be feasibly targeted in vivo. Transgenic overexpression of exercise-induced CITED4 has been shown to protect against adverse remodeling after ischemia/reperfusion injury (IRI). Here we investigated whether somatic gene transfer of CITED4 in a clinically relevant time frame could promote recovery after IRI. Cardiac CITED4 gene delivery via intravenous AAV9 injections in wild type mice led to an approximately 3-fold increase in cardiac CITED4 expression. After 4 weeks, CITED4-treated animals developed physiological cardiac hypertrophy without adverse remodeling. In IRI, delivery of AAV9-CITED4 after reperfusion resulted in a 6-fold increase in CITED4 expression 1 week after surgery, as well as decreased apoptosis, fibrosis, and inflammatory markers, culminating in a smaller scar and improved cardiac function 8 weeks after IRI, compared with control mice receiving AAV9-GFP. Somatic gene transfer of CITED4 induced a phenotype suggestive of physiological cardiac growth and mitigated adverse remodeling after ischemic injury. These studies support the feasibility of CITED4 gene therapy delivered in a clinically relevant time frame to mitigate adverse ventricular remodeling after ischemic injury.

DNA-binding protein-A: a multitool in tubular epithelial cells.

Acute kidney injury is still associated with high morbidity and mortality. Reichardt et al. investigated DNA-binding protein-A (Ybx3) in acute kidney injury induced by ischemia-reperfusion injury and found that mice lacking Ybx3 have altered mitochondrial function and increased antioxidant activity, making them more resistant to ischemia-reperfusion injury-acute kidney injury. The study highlights a new role of the multifaceted protein DNA-binding protein-A, which could be potentially therapeutically exploited.

Salvaging donated kidneys from prolonged warm ischemia during ex vivo hypothermic oxygenated perfusion.

Prolonged warm ischemic is the main cause discarding donated organs after cardiac death. Here, we identified that prolonged warm ischemic time induced disseminated intravascular coagulation and severe capillary vasospasm after cardiac death of rat kidneys. Additionally, we found a significant accumulation of fibrinogen in a hypoxic cell culture of human umbilical vein epithelial cells and in isolated kidneys exposed to prolonged warm ischemic following flushing out of blood. However, pre-flushing the kidney with snake venom plasmin in a 90-minute warm ischemic model maximized removal of micro thrombi and facilitated the delivery of oxygen and therapeutic agents. Application of carbon monoxide-releasing CORM-401 during ex vivo hypothermic oxygenated perfusion achieved multipath protective effects in prolonged warm ischemic kidneys. This led to significant improvements in perfusion parameters, restoration of the microcirculation, amelioration of mitochondrial injury, oxidative stress, and apoptosis. This benefit resulted in significantly prolonged warm ischemic kidney recipient survival rates of 70%, compared with none in those receiving ex vivo hypothermic oxygenated perfusion alone. Significantly, ex vivo hypothermic oxygenated perfusion combined with cytoprotective carbon monoxide releasing CORM-401 treatment meaningfully protected the donated kidney after cardiac death from ischemia-reperfusion injury by reducing inflammation, oxidative stress, apoptosis, and pathological damage. Thus, our study suggests a new combination treatment strategy to potentially expand the donor pool by increasing use of organs after cardiac death and salvaging prolonged warm ischemic kidneys.

Comparison of the effects of normothermic machine perfusion and cold storage preservation on porcine intestinal allograft regenerative potential and viability.

Intestinal transplantation (IT) is the final treatment option for intestinal failure. Static cold storage (CS) is the standard preservation method used for intestinal allografts. However, CS and subsequent transplantation induce ischemia-reperfusion injury (IRI). Severe IRI impairs epithelial barrier function, including loss of intestinal stem cells (ISC), critical to epithelial regeneration. Normothermic machine perfusion (NMP) preservation of kidney and liver allografts minimizes CS-associated IRI; however, it has not been used clinically for IT. We hypothesized that intestine NMP would induce less epithelial injury and better protect the intestine's regenerative ability when compared with CS. Full-length porcine jejunum and ileum were procured, stored at 4 °C, or perfused at 34 °C for 6 hours (T6), and transplanted. Histology was assessed following procurement (T0), T6, and 1 hour after reperfusion. Real-time quantitative reverse transcription polymerase chain reaction, immunofluorescence, and crypt culture measured ISC viability and proliferative potential. A greater number of NMP-preserved intestine recipients survived posttransplant, which correlated with significantly decreased tissue injury following 1-hour reperfusion in NMP compared with CS samples. Additionally, ISC gene expression, spheroid area, and cellular proliferation were significantly increased in NMP-T6 compared with CS-T6 intestine. NMP appears to reduce IRI and improve graft regeneration with improved ISC viability and proliferation.

Polyphyllin I alleviates neuroinflammation after cerebral ischemia-reperfusion injury via facilitating autophagy-mediated M2 microglial polarization.

Microglial activation and polarization play a central role in poststroke inflammation and neuronal damage. Modulating microglial polarization from pro-inflammatory to anti-inflammatory phenotype is a promising therapeutic strategy for the treatment of cerebral ischemia. Polyphyllin I (PPI), a steroidal saponin, shows multiple bioactivities in various diseases, but the potential function of PPI in cerebral ischemia is not elucidated yet. In our study, the influence of PPI on cerebral ischemia-reperfusion injury was evaluated. Mouse middle cerebral artery occlusion (MCAO) model and oxygen-glucose deprivation and reoxygenation (OGD/R) model were constructed to mimic cerebral ischemia-reperfusion injury in vivo and in vitro. TTC staining, TUNEL staining, RT-qPCR, ELISA, flow cytometry, western blot, immunofluorescence, hanging wire test, rotarod test and foot-fault test, open-field test and Morris water maze test were performed in our study. We found that PPI alleviated cerebral ischemia-reperfusion injury and neuroinflammation, and improved functional recovery of mice after MCAO. PPI modulated microglial polarization towards anti-inflammatory M2 phenotype in MCAO mice in vivo and post OGD/R in vitro. Besides, PPI promoted autophagy via suppressing Akt/mTOR signaling in microglia, while inhibition of autophagy abrogated the effect of PPI on M2 microglial polarization after OGD/R. Furthermore, PPI facilitated autophagy-mediated ROS clearance to inhibit NLRP3 inflammasome activation in microglia, and NLRP3 inflammasome reactivation by nigericin abolished the effect of PPI on M2 microglia polarization. In conclusion, PPI alleviated post-stroke neuroinflammation and tissue damage via increasing autophagy-mediated M2 microglial polarization. Our data suggested that PPI had potential for ischemic stroke treatment.

Insights on Protective Effect of Platelet Rich Plasma and Tadalafil on Testicular Ischemia/Reperfusion Injury in Rats Exposed to Testicular Torsion/Detorsion.

BACKGROUND/AIMS: Ischemic reperfusion (I-R) injury is greatly influenced by the testicular torsion/detorsion process (TDP). In this instance, the anti-inflammatory properties of plateletrich plasma (PRP) combined with tadalafil (Td) significantly promote tissue healing in the I-R injury model. METHODS: Five groups of rats were created: the control group, the I-R group not receiving any therapy, the I-R group receiving a single dosage of Td (0.25 mg/kg, I.P.), the I-R group receiving a single dose of PRP (80 l, intratesticular), and the I-R group receiving both Td and PRP. Sperm morphology, motility, and histology were assessed. The levels of TNF-, BAX, antioxidant status, and testosterone were measured. Additionally, E-selectin expression was done. RESULTS: PRP reduced oxidative stress, inflammation, and apoptosis while also boosting testosterone levels, which alleviated I-R injury. Otherwise, PRP reduces E-selectin expression, which modifies the pathways that control endothelial function. Td also partially demonstrated its testicular-protective activity at the same time. CONCLUSION: PRP's proven anti-inflammatory, antioxidant, and antiapoptotic potentials make it a natural treatment for testicular harm caused by tadalafil. For the first time, it was demonstrated that PRP therapy restored the functionality of the vascular endothelium, specifically the control of E-selectin expression. Combining Td and PRP therapy may be a promising strategy for improving response to PDE5 inhibitors.

Gut-derived trimethylamine N-oxide promotes CCR2-mediated macrophage infiltration in acute kidney injury.

BACKGROUND: Inflammation is crucial in the development of acute kidney injury (AKI) and subsequent chronic kidney disease (CKD) following renal ischaemia-reperfusion (IR) injury. Gut microbiota metabolites trigger inflammation and affect IR-induced renal damage. Yet the driving factors and mechanisms are unclear. Trimethylamine N-oxide (TMAO), a gut-derived choline metabolite, is a strong pro-inflammatory factor that increases in patients with AKI and CKD. We hypothesized that TMAO can promote renal injury caused by IR. METHODS: Mice subjected to unilateral renal IR to induce AKI and CKD were fed a high-choline diet to observe the effects of TMAO on kidney inflammation, fibrosis and macrophage dynamics. RESULTS: A choline-rich diet altered the gut microbiota and elevated TMAO levels, exacerbating IR-induced AKI and subsequent CKD. Single-cell analysis identified a distinct subset of CCR2+ macrophages derived from monocytes as key responders to TMAO, intensifying immune cell interactions and worsening renal injury. TMAO promoted sustained CCR2 expression after IR, increasing macrophage infiltration. CCR2 deletion and antagonist RS-102895 improved TMAO-induced inflammation and fibrosis and alleviated renal injury induced by IR. CONCLUSIONS: Our study provides valuable insights into the link between TMAO and IR-induced renal inflammation and fibrosis, emphasizing the critical role of TMAO-mediated macrophage infiltration via CCR2 as a key therapeutic target in the acute and chronic phases after IR.

Therapeutic Use of Carbon Monoxide in Ex-Vivo Lung Perfusion in Donor With Prolonged Cold Ischemia.

INTRODUCTION: Carbon monoxide (CO) has been shown to exert protective effects in multiple organs following ischemic injury, including the lung. The purpose of this study was to examine the effects of CO administration during ex vivo lung perfusion (EVLP) on lung grafts exposed to prolonged cold ischemia. METHODS: Ten porcine lungs were subjected to 18 h of cold ischemia followed by 6 h of EVLP. Lungs were randomized to EVLP alone (control, n = 5) or delivery of 500 ppm of CO during the 1st hour of EVLP (treatment, n = 5). Following EVLP, the left lungs were transplanted and reperfused for 4 h. RESULTS: At the end of EVLP, pulmonary vascular resistance (P = 0.007) and wet to dry lung weight ratios (P = 0.027) were significantly reduced in CO treated lungs. Posttransplant, lung graft PaO2/FiO2 (P = 0.032) and compliance (P = 0.024) were significantly higher and peak airway pressure (P = 0.032) and wet to dry ratios (P = 0.003) were significantly lower in CO treated lungs. Interleukin-6 was significantly reduced in plasma during reperfusion in the CO treated group (P = 0.040). CONCLUSIONS: In this preclinical porcine model, CO application during EVLP resulted in better graft performance and outcomes after reperfusion.

Luminal Delivery of Pectin-Modified Oxygen Microbubbles Mitigates Rodent Experimental Intestinal Ischemia.

INTRODUCTION: Ischemic gut injury is common in the intensive care unit, impairs gut barrier function, and contributes to multiorgan dysfunction. One novel intervention to mitigate ischemic gut injury is the direct luminal delivery of oxygen microbubbles (OMB). Formulations of OMB can be modified to control the rate of oxygen delivery. This project examined whether luminal delivery of pectin-modified OMB (OMBp5) can reduce ischemic gut injury in a rodent model. METHODS: The OMBp5 formulation was adapted to improve delivery of oxygen along the length of small intestine. Adult Sprague-Dawley rats (n = 24) were randomly allocated to three groups: sham-surgery (SS), intestinal ischemia (II), and intestinal ischemia plus luminal delivery of OMBp5 (II + O). Ischemia-reperfusion injury was induced by superior mesenteric artery occlusion for 45 min followed by reperfusion for 30 min. Outcome data included macroscopic score of mucosal injury, the histological score of gut injury, and plasma biomarkers of intestinal injury. RESULTS: Macroscopic, microscopic data, and intestinal injury biomarker results demonstrated minimal intestinal damage in the SS group and constant damage in the II group. II + O group had a significantly improved macroscopic score throughout the gut mucosa (P = 0.04) than the II. The mean histological score of gut injury for the II + O group was significantly improved on the II group (P ≤ 0.01) in the proximal intestine only, within 30 cm of delivery. No differences were observed in plasma biomarkers of intestinal injury following OMBp5 treatment. CONCLUSIONS: This proof-of-concept study has demonstrated that luminal OMBp5 decreases ischemic injury to the proximal small intestine. There is a need to improve oxygen delivery over the full length of the intestine. These findings support further studies with clinically relevant end points, such as systemic inflammation and vital organ dysfunction.

Impact of a Single Dose of Alpha-1-Antitrypsin in a Rat Model of Bilateral Kidney Ischemia Reperfusion Injury.

INTRODUCTION: Renal ischemia reperfusion injury is a major cause of perioperative acute kidney injury. Alpha-1-antitrypsin (AAT), a protease inhibitor, might improve outcomes by reducing inflammation and apoptosis. We investigated the effects of a single intravenous dose of AAT immediately before ischemia in a rat bilateral renal clamping model. METHODS: Both renal pedicles of male Sprague-Dawley rats were clamped (45 min). Plasma and renal tissue were collected at 3 h, 24 h, and 7 d. Intravenous AAT (60 mg/kg) was administered 5 min before clamping. Controls received saline. Shams underwent surgery without clamping or injection. Kidney function was assessed by plasma creatinine; injury by aspartate aminotransferase, heart-type-fatty-acid-binding-protein, and histopathology. Renal gene expression of tumor necrosis factor α, interleukin (IL)-6, heat shock protein 70, Chemokine (C-X-C motif) ligand 2, cyclo-oxygenase 2, endothelin-1, IL-10, heme oxygenase 1, B-cell lymphoma 2, and bcl-2-like protein 4 were determined by quantitative reverse transcriptase polymerase chain reaction. RESULTS: None of the 3 h and 24 h end points were different between Control and AAT. In Sham, survival was 100% (6/6), 33% in Control (2/6), and 83% (5/6) in AAT (overall log-rank 0.03). At 7 d, plasma creatinine was lower with higher glomerular filtration rate in surviving AAT treated animals compared to Control (P < 0.001, P 0.03, respectively). These also had lower tumor necrosis factor α and IL-6 gene expression (P 0.001, P < 0.001, respectively). CONCLUSIONS: These data suggest that a single intravenous dose of AAT immediately before ischemia might affect proinflammatory gene expression, glomerular filtration rate and animal survival at 1 wk after reperfusion despite an absence of improvement in early renal function and injury. These findings deserve further investigating in sufficiently powered studies including both sexes.

Asystolic donor warm ischemia time is associated with development of postreperfusion syndrome in donation after circulatory death liver transplant.

BACKGROUND: Individual events during donation after circulatory death (DCD) procurement, such as hypotensive or hypoxic warm ischemia, or circulatory arrest are all a part of donor warm ischemia time (dWIT), and may have differing effects on the outcome of the liver graft. This study aimed to identify risk factors for postreperfusion syndrome (PRS), a state of severe hemodynamic derangement following graft reperfusion, and its impact on DCD liver transplantation (LT) outcomes. METHODS: This was a retrospective analysis using 106 DCD LT. Detailed information for events during procurement (withdrawal of life support; systolic blood pressure < 80 mmHg; oxygen saturation < 80%; circulatory arrest; aortic cold perfusion) and their association with the development of PRS were examined using logistic regression. RESULTS: The overall incidence of PRS was 26.4%, occurring in 28 patients. Independent risk factors for PRS were asystolic dWIT (odds ratio (OR) 3.65, 95% confidence interval (CI) 1.38-9.66) and MELD score (OR 1.06, 95% CI 1.01-1.10). Total bilirubin was significantly higher in the PRS group at postoperative day (POD) 1 (p = .02; 5.2 mg/dL vs. 3.4 mg/dL), POD 3 (p = .049; 4.5 mg/dL vs. 2.8 mg/dL), and POD 7 (p = .04; 3.1 mg/dL vs. 1.9 mg/dL). Renal replacement therapy after LT was more likely to be required in the PRS group (p = .01; 48.2% vs. 23.1%). CONCLUSION: Asystolic dWIT is a risk factor for the development of PRS in DCD LT. Our results suggest that asystolic dWIT should be considered when selecting DCD liver donors.

Comparative Analysis of Ischemia-Reperfusion Injury in Heart Transplantation: A Single-Center Study Evaluating Conventional Ice-Cold Storage versus the Paragonix SherpaPak Cardiac Transport System.

BACKGROUND: Since the 2018 allocation system change in heart transplantation (HT), ischemic times have increased, which may be associated with peri-operative and post-operative complications. This study aimed to compare ischemia reperfusion injury (IRI) in hearts preserved using ice-cold storage (ICS) and the Paragonix SherpaPak TM Cardiac Transport System (CTS). METHODS: From January 2021 to June 2022, consecutive endomyocardial biopsies from 90 HT recipients were analyzed by a cardiac pathologist in a single-blinded manner: 33 ICS and 57 CTS. Endomyocardial biopsies were performed at three-time intervals post-HT, and the severity of IRI manifesting histologically as coagulative myocyte necrosis (CMN) was evaluated, along with graft rejection and graft function. RESULTS: The incidence of IRI at weeks 1, 4, and 8 post-HT were similar between the ICS and CTS groups. There was a 59.3% statistically significant reduction in CMN from week 1 to 4 with CTS, but not with ICS. By week 8, there were significant reductions in CMN in both groups. Only 1 out of 33 (3%) patients in the ICS group had an ischemic time >240 mins, compared to 10 out of 52 (19%) patients in the CTS group. During the follow-up period of 8 weeks to 12 months, there were no significant differences in rejection rates, formation of de novo donor-specific antibodies and overall survival between the groups. CONCLUSION: The CTS preservation system had similar rates of IRI and clinical outcomes compared to ICS despite longer overall ischemic times. There is significantly more recovery of IRI in the early post operative period with CTS. This study supports CTS as a viable option for preservation from remote locations, expanding the donor pool.

Protective Effects of Hydrogen Gas Inhalation for Hindlimb Ischaemia-Reperfusion Injury in a Mouse Model.

OBJECTIVE: Ischaemia-reperfusion (I/R) injury is a severe post-operative complication that triggers an inflammatory response and causes severe damage. Hydrogen gas has anti-oxidant and anti-apoptotic properties and has been shown to be safe in humans. The study aimed to investigate whether hydrogen gas protects against skeletal muscle I/R injury. METHODS: Experimental basic research using mice. A total of 160 eight to 10 week old albino laboratory bred strain of house mice (25.8 ± 0.68 g) were used in this study. The mice were cable tied to the hindlimb under anaesthesia and then placed in an anaesthesia box filled with air and 2% isoflurane (control group); 80 mice were additionally subjected to 1.3% hydrogen gas in this mix (hydrogen group). After two hours, the cable ties were removed to initiate reperfusion, and hydrogen inhalation lasted for six hours in the hydrogen group. After six hours, the mice were taken out of the box and kept in cages under standard conditions until time for observation at 16 different time points after reperfusion: zero, two, four, six, eight, and 10 hours and one, two, three, four, five, six, seven, 14, 21, and 28 days. Five mice were sacrificed using excess anaesthesia at each time point, and the bilateral hindlimb tissues were harvested. The inflammatory effects of the I/R injury were assessed by evaluating serum interleukin-6 concentrations using enzyme linked immunosorbent assay, as well as histological and immunohistochemical analyses. Untreated mice with I/R injury were used as controls. RESULTS: Hydrogen gas showed protective effects associated with a reduction in inflammatory cell infiltration (neutrophils, macrophages, and lymphocytes), a reduced area of damaged muscle, maintenance of normal muscle cells, and replacement of damaged muscle cells with neoplastic myocytes. CONCLUSION: Inhalation of hydrogen gas had a protective effect against hindlimb I/R injury in mice, in part by reducing inflammatory cell infiltration and in part by preserving normal muscle cells.

Extrahepatic Bile Duct Organoids as a Model to Study Ischemia/Reperfusion Injury During Liver Transplantation.

Biliary complications are still a major cause for morbidity and mortality after liver transplantation (LT). Ischemia/reperfusion injury (IRI) leads to disruption of the biliary epithelium. We introduce a novel model to study the effect of IRI on human cholangiocytes using extrahepatic cholangiocyte organoids (ECOs). Extrahepatic bile duct tissue was collected during LT at static cold storage and after reperfusion (n = 15); gallbladder tissue was used for controls (n = 5). ECOs (n = 9) were cultured from extrahepatic biliary tissue, with IRI induced in an atmosphere of 95% air (nitrogen), 1% O2 and 5% CO2for 48 h, followed by 24 h of reoxygenation. Qualitative and quantitative histology and qRT-PCR were performed to discern phenotype, markers of hypoxia, programmed cell death and proliferation. ECOs self-organized into circular structures resembling biliary architecture containing cholangiocytes that expressed EpCAM, CK19, LGR5 and SOX-9. After hypoxia, ECOs showed increased expression of VEGF A (p < 0.0001), SLC2A1 (p < 0.0001) and ACSL4 (p < 0.0001) to indicate response to hypoxic damage and subsequent programmed cell death. Increase in cyclin D1 (p < 0.0001) after reoxygenation indicated proliferative activity in ECOs. Therefore, ECO structure and response to IRI are comparable to that found in-vivo, providing a suitable model to study IRI of the bile duct in-vitro.

HOPE Mitigates Ischemia-Reperfusion Injury in Ex-Situ Split Grafts: A Comparative Study With Living Donation in Pediatric Liver Transplantation.

Optimizing graft preservation is key for ex-situ split grafts in pediatric liver transplantation (PSLT). Hypothermic Oxygenated Perfusion (HOPE) improves ischemia-reperfusion injury (IRI) and post-operative outcomes in adult LT. This study compares the use of HOPE in ex-situ partial grafts to static cold storage ex-situ partial grafts (SCS-Split) and to the gold standard living donor liver transplantation (LDLT). All consecutive HOPE-Split, SCS-Split and LDLT performed between 2018-2023 for pediatric recipients were included. Post-reperfusion syndrome (PRS, drop ≥30% in systolic arterial pressure) and reperfusion biopsies served as early indicators of IRI. We included 47 pediatric recipients (15 HOPE-Split, 17 SCS-Split, and 15 LDLT). In comparison to SCS-Split, HOPE-Split had a significantly shorter cold ischemia time (CIT) (470min vs. 538 min; p =0.02), lower PRS rates (13.3% vs. 47.1%; p = 0.04) and a lower IRI score (3 vs. 4; p = 0.03). The overall IRI score (3 vs. 3; p = 0.28) and PRS (13.3% vs. 13.3%; p = 1) after HOPE-Split were comparable to LDLT, despite a longer CIT (470 min vs. 117 min; p < 0.001). Surgical complications, one-year graft, and recipient survival did not differ among the groups. In conclusion, HOPE-Split mitigates early IRI in pediatric recipients in comparison to SCS-Split, approaching the gold standard of LDLT.

HMGB1-Mediated Neutrophil Extracellular Trap Formation Exacerbates Intestinal Ischemia/Reperfusion-Induced Acute Lung Injury.

Influx of activated neutrophils into the lungs is the histopathologic hallmark of acute lung injury (ALI) after intestinal ischemia/reperfusion (I/R). Neutrophils can release DNA and granular proteins to form cytotoxic neutrophil extracellular traps (NETs), which promotes bystander tissue injury. However, whether NETs are responsible for the remote ALI after intestinal I/R and the mechanisms underlying the dissemination of harmful gut-derived mediators to the lungs are unknown. In the C57BL/6J mouse intestinal I/R model, DNase I-mediated degradation and protein arginine deiminase 4 (PAD4) inhibitor-mediated inhibition of NET treatments reduced NET formation, tissue inflammation, and pathological injury in the lung. High-mobility group protein B1 (HMGB1) blocking prevented NET formation and protected against tissue inflammation, as well as reduced cell apoptosis and improved survival rate. Moreover, recombinant human HMGB1 administration further drives NETs and concurrent tissue toxic injury, which in turn can be reversed by neutrophil deletion via anti-Ly6G Ab i.p. injection. Furthermore, global MyD88 deficiency regulated NET formation and alleviated the development of ALI induced by intestinal I/R. Thus, HMGB1 released from necroptotic enterocytes caused ALI after intestinal I/R by inducing NET formation. Targeting NETosis and the HMGB1 pathway might extend effective therapeutic strategies to minimize intestinal I/R-induced ALI.

Remote ischemic preconditioning versus sham-control for prevention of anastomotic leakage after resection for rectal cancer (RIPAL trial): a pilot randomized controlled, triple-blinded monocenter trial.

PURPOSE: Remote ischemic preconditioning (RIPC) reportedly reduces ischemia‒reperfusion injury (IRI) in various organ systems. In addition to tension and technical factors, ischemia is a common cause of anastomotic leakage (AL) after rectal resection. The aim of this pilot study was to investigate the potentially protective effect of RIPC on anastomotic healing and to determine the effect size to facilitate the development of a subsequent confirmatory trial. MATERIALS AND METHODS: Fifty-four patients with rectal cancer (RC) who underwent anterior resection were enrolled in this prospectively registered (DRKS0001894) pilot randomized controlled triple-blinded monocenter trial at the Department of Surgery, University Medicine Mannheim, Mannheim, Germany, between 10/12/2019 and 19/06/2022. The primary endpoint was AL within 30 days after surgery. The secondary endpoints were perioperative morbidity and mortality, reintervention, hospital stay, readmission and biomarkers of ischemia‒reperfusion injury (vascular endothelial growth factor, VEGF) and cell death (high mobility group box 1 protein, HMGB1). RIPC was induced through three 10-min cycles of alternating ischemia and reperfusion to the upper extremity. RESULTS: Of the 207 patients assessed, 153 were excluded, leaving 54 patients to be randomized to the RIPC or the sham-RIPC arm (27 each per arm). The mean age was 61 years, and the majority of patients were male (37:17 (68.5:31.5%)). Most of the patients underwent surgery after neoadjuvant therapy (29/54 (53.7%)) for adenocarcinoma (52/54 (96.3%)). The primary endpoint, AL, occurred almost equally frequently in both arms (RIPC arm: 4/25 (16%), sham arm: 4/26 (15.4%), p = 1.000). The secondary outcomes were comparable except for a greater rate of reintervention in the sham arm (9 (6-12) vs. 3 (1-5), p = 0.034). The median duration of endoscopic vacuum therapy was shorter in the RIPC arm (10.5 (10-11) vs. 38 (24-39) days, p = 0.083), although the difference was not statistically significant. CONCLUSION: A clinically relevant protective effect of RIPC on anastomotic healing after rectal resection cannot be assumed on the basis of these data.

Hypothermic Oxygenated machine PErfusion for high-risk liver grafts for transplantation: A systematic review and meta-analysis.

BACKGROUND: Hypothermic Oxygenated machine PErfusion (HOPE) can reduce ischemic reperfusion injury and improve outcomes for liver transplant recipients. However, the effect of HOPE on high-risk extended criteria donor (ECD) and donation after circulatory death determination (DCDD) grafts is incomplete, despite the expectation that this cohort benefit maximally from HOPE. Accordingly, this paper aims to characterize the effect of HOPE on ECD and DCDD grafts. METHODS: This study includes all papers comparing HOPE to static cold storage for high-risk ECD and DCDD grafts. Systematic searches of Medline, Embase, and Scopus were completed using the terms "HOPE" OR "hypothermic oxygenated machine perfusion" AND "liver transplantation". Data were extracted and analyzed using IBM SPSS to perform the meta-analysis. RESULTS: A total of 2286 records were identified, with 10 meeting the inclusion criteria. Overall, the quality of evidence is heterogenous with many papers relying on retrospective controls. However, pooled analysis demonstrates HOPE to significantly reduce the rate of early allograft dysfunction, 12-month graft failure, re-transplantation, total biliary complications, and non-anastomotic strictures for high-risk grafts. CONCLUSIONS: There is good evidence that HOPE improves outcomes following liver transplantation across a number of biochemical and clinical endpoints for high-risk grafts. Of note, the reduction in biliary complications and re-transplantation is particularly significant given the morbidity associated with these endpoints. However, further, high-quality prospective trials with contemporary controls and clinically relevant primary endpoints are needed to better define the impact of HOPE for this cohort of grafts.

Hyperoxia-Induced Secondary Respiratory Failure in a Systemic Ischaemia-Reperfusion Injury.

Recent studies revealed that excessive supplemental oxygen, such as inhaled 100% O2, damages various organ functions in post-cardiac arrest (CA) patients. Optimal indicators of supplemental oxygen are therefore important to prevent hyperoxic organ injuries. In this study, we evaluated a hyperoxic pulmonary injury and assessed the association between alveolar-arterial oxygen difference (AaDO2) and a degree of lung oedema. In this study, we focused on the hyperoxia-induced lung injury and its association with changes of gas-exchange parameters in post-CA rats. Rats were resuscitated from 10 min of asphyxial CA and stratified into two groups: those with inhaled 100% O2 (CA-FiO2 1.0) and those with 30% O2 (CA-FiO2 0.3). We prepared a sham surgery group for comparison (sham-FiO2 0.3). After 2 h, animals were sacrificed, and the lung wet-to-dry (W/D) weight ratio was measured. We collected blood gas results and measured the ratio of partial pressure arterial oxygen and fraction of inspired oxygen (p/f ratio), and calculated AaDO2. The lung W/D ratio in the CA-FiO2 1.0 group (5.8 ± 0.26) was higher than in the CA-FiO2 0.3 (4.6 ± 0.42) and sham-FiO2 0.3 groups (4.6 ± 0.38, p < 0.01). There was a significant difference in AaDO2 between CA-FiO2 1.0 (215 ± 49.3) and, CA-FiO2 0.3 (36.8 ± 32.3), and sham-FiO2 0.3 groups (49.0 ± 20.5, p < 0.01). There were also significant changes in pH and blood lactate levels in the early phase among the three groups. AaDO2 showed the strongest correlation with W/D ratio (r = 0.9415, p < 0.0001), followed by pH (r = -0.5131, p = 0.0294) and p/f ratio (r = -0.3861, p = 0.1135). Hyperoxic injury might cause the pulmonary oedema after CA. Measuring respiratory quotient (RQ) in rodents enabled an accurate calculation for AaDO2 at a variety level of inhaled O2. Given that AaDO2 measurement is non-invasive, we therefore consider AaDO2 to be a potentially optimal indicator of post-CA hyperoxic pulmonary injury.