Cold Static Preservation Research Articles

Ex vivo perfusion induces a time- and perfusate-dependent molecular repair response in explanted porcine lungs.

Ex vivo lung perfusion (EVLP) shows promise in ameliorating pretransplant acute lung injury (ALI) and expanding the donor organ pool, but the mechanisms of ex vivo repair remain poorly understood. We aimed to assess the utility of gene expression for characterizing ALI during EVLP. One hundred sixty-nine porcine lung samples were collected in vivo (n = 25), after 0 (n = 11) and 12 (n = 11) hours of cold static preservation (CSP), and after 0 (n = 57), 6 (n = 8), and 12 (n = 57) hours of EVLP, utilizing various ventilation and perfusate strategies. The expression of 53 previously described ALI-related genes was measured and correlated with function and histology. Twenty-eight genes were significantly upregulated and 6 genes downregulated after 12 hours of EVLP. Aggregate gene sets demonstrated differential expression with EVLP (P < .001) but not CSP. Upregulated 28-gene set expression peaked after 6 hours of EVLP, whereas downregulated 6-gene set expression continued to decline after 12 hours. Cellular perfusates demonstrated a greater reduction in downregulated 6-gene set expression vs acellular perfusate (P < .038). Gene set expression correlated with relevant functional and histologic parameters, including P/F ratio (P < .001) and interstitial inflammation (P < .005). Further studies with posttransplant results are warranted to evaluate the clinical significance of this novel molecular approach for assessing organ quality during EVLP.

The ex vivo evaluation of oxygenated blood continuous perfusion to prevent ischemic-reperfusion injury of donor lung

Objective To study the protective effect of ex vivo perfusion to prevent donor-lung injury. Methods After being flushed with Celsior solution, the donor lungs were divided to control group (4 ℃ cold static preservation, subgroups-C4, C8, C12, C18) and experimental group (ex vivo oxygenated blood continuous perfusion, subgroups-T4, T8, T12, T18). Then the donor lungs connected with ventilator and ex vivo perfusion system to worked for 6 h. Lung ventilation resistance (LR), the left inferior pulmonary vein blood PO2 (LIPV-PO2), the left inferior pulmonary vein blood PCO2 (LIPV-PCO2), and lung water content (LWC), were evaluated. Lung edema were studied by light microscopic observation and apoptotic cells (AC) were detected by terminal-deoxynucleotidyl transferase mediated nick end labeling (TUNEL). Results Lung function evaluation: (1) Lung function of experiment group was relatively stable, LR and LWC of T18 were significantly more than T4 (P=0.012, 0.010, respectively); LR and LWC of C12 were significantly more than C4 (P=0.018, 0.015, respectively); In the same time point LR and LWC of T12 and T18 were significantly less than C12 and C18 respectively (LR: P=0.025, 0.028; LWC: P=0.021, 0.027; respectively); (2) Lung injury evaluation: pulmonary edema classification (LEC) and AC of T18 were significantly more than T4 (P=0.023, 0.020, respectively); LEC and AC of C12 and C18 were significantly more than C4 (PLEC=0.023, 0.020; PAC=0.015, 0.011, respectively); LEC and AC of C18 were significantly more than T18 (P=0.007, 0.026, respectively). Conclusion Ex vivo oxygenated blood continuous perfusion without ventilator ameliorates hypothermic time-dependent ischemic-reperfusion injury. But further systems evaluation in complete physiologic condition is necessary. Key words: Lung transplatation; Lung preservation; Lung injury; Ex vivo perfusion

Advances in machine perfusion, organ preservation, and cryobiology: potential impact on vascularized composite allotransplantation.

In this review, we discuss novel strategies that allow for extended preservation of vascularized composite allografts and their potential future clinical implications for the field of vascularized composite allotransplantation (VCA). The current gold standard in tissue preservation - static cold preservation on ice - is insufficient to preserve VCA grafts for more than a few hours. Advancements in the field of VCA regarding matching and allocation, desensitization, and potential tolerance induction are all within reasonable reach to achieve; these are, however, constrained by limited preservation time of VCA grafts. Although machine perfusion holds many advantages over static cold preservation, it currently does not elongate the preservation time. More extreme preservation techniques, such as cryopreservation approaches, are, however, specifically difficult to apply to composite tissues as the susceptibility to ischemia and cryoprotectant agents varies greatly by tissue type. In the current scope of extended preservation protocols, high subzero approaches of VCA grafts will be particularly critical enabling technologies for the implementation of tolerance protocols clinically. Ultimately, advances in both preservation techniques and tolerance induction have the potential to transform the field of VCA and eventually lead to broad applications in reconstructive transplantation.

One-year experience with ex vivo lung perfusion: Preliminary results from a single center.

To enlarge the donor pool for lung transplantation, an increasing number of extended criteria donor lungs are used. However, in more than 50% of multi-organ donors the lungs are not used. Ex vivo lung perfusion offers a unique possibility to evaluate and eventually recondition the injured donor lungs. The aim of our study was to assess the enlargement of the donor pool and the outcome with extended criteria donor lungs after ex vivo lung perfusion. Data were prospectively collected in our lung transplant database. We compared the results of lung transplants after ex vivo lung perfusion with those after conventional cold static preservation. In total, 11 extended criteria donor lungs processed with ex vivo lung perfusion and 41 cold static preservation lungs transplanted consecutively between May 2016 and May 2017 were evaluated. Normothermic ex vivo lung perfusion was performed according to the Toronto protocol for 4 h. Cold static preservation lungs were stored in low-potassium dextran solution. Ex vivo lung perfusion lungs before procurement had significantly lower PaO2/FiO2 (P/F) ratios and more X-ray abnormalities. There were no statistically significant differences for pre-donation ventilation time, smoking history, or sex. After reconditioning with ex vivo lung perfusion, 9 out of 11 processed lungs were considered suitable and successfully transplanted. The mean postoperative ventilation time and in-hospital stay were not significantly different in ex vivo lung perfusion and cold static preservation recipients. Ex vivo lung perfusion can safely be used in the evaluation of lungs initially considered not suitable for transplantation. The primary outcome was not negatively affected and normothermic ex vivo lung perfusion is a useful tool to increase the usage of potentially transplantable lungs.

Comprehensive Review on Custodiol-N (HTK-N) and its Molecular Side of Action for Organ Preservation

The later fate of a graft is highly dependent on its initial quality. Aside from that the three predominant phases during transplantation (Tx) organ retrieval, cold static preservation and reperfusion cause in a direct and indirect manner graft injury. There is complex ischemia reperfusion injury (IRI) triggered during the whole process of Tx which contributes to further damage of the graft. The today's organ preservation with commercially available solutions that all have toxic potential per se is still imperfect. Thus, improved preservation solutions are desperately needed to be able to even safely preserve grafts from extended criteria donors which are more susceptible to especially IRI. Most recently, a modified less toxic histidine-tryptophan-ketoglutarate (HTK; Custodiol®) the so called histidine-tryptophan-ketoglutarate-N (HTK-N) for both better cardioplegia and organ preservation for Tx has been developed. It is characterized as an electrolyte balanced, iron chelatorsupplemented, and amino acid-fortified organ preservation solution with replaced buffer ameliorating resistance to injury during the cold static preservation with subsequent IRI. Numerous in vitro and in vivo experiments have shown the superiority of the HTK-N solution in ROS generation, microcirculation, and subsequent inflammatory response compared with HTK. According to data available to date, HTK-N has both lower cytotoxicity and higher protective potential than HTK. First clinical studies on both HTK-N for cardioplegia in cardiac surgery and for organ preservation for transplantation have been performed or are ongoing. In this review, the novelty and composition of HTK-N and studies investigating the potential of this new solution are focussed, after summarizing the most relevant molecular mechanisms of IRI.

Does Ischemia Free Liver Procurement Under Normothermic Perfusion Benefit the Outcome of Liver Transplantation?

BackgroundIn contrast to conventional static cold preservation, normothermic machine perfusion (NMP) provides a beneficial alternative preservation of donor livers. However, the liver still suffered cold ischemic injury before attaching to the perfusion device.Material/MethodsTo prevent cold ischemic injury during procurement, we describe a novel procedure called ischemia-free liver procurement (IFLP) under NMP. Two liver grafts were procured from brain death donor under NMP and underwent 2-hour ex vivo NMP followed by 3 and 6 hours of static cold preservation. From procurement to post-transplantation course, evidence was collected to prove that IFLP is safe and benefits recipients.ResultsThe post-transplantation course was uneventful, and the liver function tests and histological study revealed minimal hepatocyte and biliary epithelium injury during the preservation.ConclusionsThis preliminary experience demonstrates the clinical feasibility and safety of IFLP under NMP which offering opportunities to increase the number of donor livers and to improve the organ function.

Effects of Short and Long Term Cold Static Preservation Followed by Normothermic Ex Vivo Lung Perfusion in a Porcine Model

Ex Vivo Lung Perfusion (EVLP) is a promising tool for evaluation and reconditioning of marginal donor lungs. However, the optimal treatment protocol is discussed controversely. After lung harvest EVLP can be performed immediately or after a prolonged cold ischemic time. We hypothesize that lung functional parameters are equally or better preserved after prolonged cold static preservation followed by EVLP compared to immediate EVLP.

Subnormothermic Regulated Hepatic Reperfusion Preserves Mitochondrial Function in Swine Liver Procured after Cardiac Death

Livers procured after cardiac death can have an extreme degree of ischemia‐reperfusion injury (IRI) and are at increased risk of graft failure after liver transplantation. Reductions in respiratory control index (RCI) and Ca2+ retention capacity (CRC) are markers of mitochondrial dysfunction and cell apoptosis. Regulated hepatic reperfusion (RHR) is a novel organ resuscitation therapy that may facilitate hepatic mitochondrial recovery from IRI using an energy substrate‐enriched, leukocyte‐depleted, oxygen‐saturated perfusate delivered in a pressure, and temperature‐controlled milieu. We used a swine donation after cardiac death (DCD) model, in which all livers were subjected to 60 min of in situ warm ischemia and 120 min of cold static (CS) preservation. All livers were subsequently reperfused and monitored for 2 h in the ex vivo perfusion machine. Four methods of reperfusion were compared with 5 animals in each treatment group. Group I: Sanguineous‐Subnormothermic (SS); Group II: RHR‐Subnormothermic (s‐RHR); Group III: Sanguineous‐Normothermic (NS); Group IV: RHR‐Normothermic (n‐RHR). Liver biopsies were collected at baseline (pre‐ischemia), at 2 h of CS following 1 h of in situ warm ischemia, and after 30 min of ex vivo reperfusion. We isolated mitochondria via differential centrifugation and measured mitochondrial bioenergetics, i.e. the ability to utilize nutrients and O2 (respiration) to generate energy (state 3 (added ADP)/state 4 (depleted ADP) respiration = RCI) and CRC, i.e. the capability of mitochondria to tolerate a challenge of 20 μM CaCl2 boluses every 90 s until mitochondrial bioenergetic failure. We found that with substrate glutamate/malate (GM), RCI with s‐RHR was 60% higher than its baseline and 2.3‐fold higher than after NS reperfusion. With substrate succinate (SC), RCI with s‐RHR reperfusion was 99% of its baseline and 2‐fold higher than NS. These changes were due mostly to the lower state 4 respiration rate in the s‐RHR group, indicating less proton leaking compared to other groups. Reperfusion lowered CRC by about 33% across all groups; however, with substrate GM, CRC after s‐RHR was 2‐fold larger than in the SS group; with substrate SC, CRC after s‐RHR was 3‐fold larger compared to other groups. Mitochondria likely play a critical role in control of hepatocyte function and viability during liver transplantation; thus preservation of mitochondrial function is critically important. Ex vivo subnormothermic‐regulated hepatic reperfusion best preserved mitochondrial function and viability. This novel strategy has potential applicability to human liver transplantation.Support or Funding InformationMCW Institutional FundingThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Two-Day Lung Preservation Followed by Lung Transplantation in a Large Animal Model Using Novel Extracellular Oxygen Carrier

To date, reliable cold static lung preservation (CSP) strategies are limited to 12h as longer times have been associated with impaired graft function. Even though lungs are stored inflated with O2, this poor performance is possibly related to poor oxygen availability and transfer at low temperatures, accumulation of reactive oxygen species, and cellular death. HEMO2Life® is an O2 therapeutic, which consists of the extracellular O2 carrier of the marine invertebrate Arenicola marina known as Hemarina-M101 (M101). M101 has potent anti-oxidative properties and each molecule can carry up to 156 O2 molecules. The purpose of this study was to investigate the use of M101 during extended CSP.

The effect of antioxidants on angiogenesis in uterine transplantation

The aim of this study was to investigate the effect of antioxidants on angiogenesis in uterine transplantation. We used 24 female rats equally divided into four groups: Group 1 had the uterus stored in HTK (Histidine–Tryptophan–Ketoglutarate) solution at 4 °C cold storage for 4 h. Group 2 had the uterine tissue stored in HTK solution combined with acetyl L-carnitine (10−8 M) for 4 h at +4 °C. The same procedures with Group 1 and 2 were repeated for 24 h for Groups 3 and 4, respectively. Histological investigation and immunohistochemical analysis were performed. Histological findings showed that storing donor uterus in HTK solution at +4° C for 24 h results in histological alteration in uterus. We also found that immunoreactivity of VEGFR-2 in all layers of rat uterus in Group 2 was lower than that in Group 1, and the expression of the uterus in Group 4 was lower than that in Group 3. We concluded that antioxidant acetyl L-carnitine, which was added to the organ preservation solution HTK, had prevented the formation of free radicals, and thus protected the uterus that was stored in short and long cold storage periods.Impact statementWhat is already known on this subject? Ischemia–reperfusion is a complex pathophysiological process involve in hypoxia and/or reoxygenation, ionic imbalance-induced oedema and acidosis, oxidative stress, mitochondrial uncoupling, coagulation and endothelium activation. The composition of preservation solutions must be adapted to the severity of ischaemia–reperfusion injuries to reduce cellular damage and inflammation and preserve graft functionality and integrity, thus improving short-term and long-term graft outcome. Clinicians use three types of composition of solution for static cold preservation: intracellular, intermediate and extracellular. HTK will be used frequently, especially with the consideration of lower price and more easy handling aspects. L-carnitine acts as an antioxidant, protects against free radicals and prevents mitochondrial damage. VEGFR-2 plays an important role in angiogenesis, chemotaxis, proliferation and migration of endothelial cells.What this study adds? In this study, we investigate the effect of antioxidants on angiogenesis in uterus transplantation. Our results showed that antioxidant acetyl L-carnitine that added to the organ preservation solution HTK, has prevented the formation of free radicals, thus protect the uterus that was stored in short and long cold storage periods.What the implications are for future studies? Therefore, we will contribute to the literature with the results of this study.

Prevention of ischemia-reperfusion lung injury during static cold preservation by supplementation of standard preservation solution with HEMO2life® in pig lung transplantation model

We describe the results of adding a new biological agent HEMO2life® to a standard preservation solution for hypothermic static lung preservation aiming to improve early functional parameters after lung transplantation. HEMO2life® is a natural oxygen carrier extracted from Arenicola marina with high oxygen affinity developed as an additive to standard organ preservation solutions. Standard preservation solution (Perfadex®) was compared with Perfadex® associated with HEMO2life® and with sham animals after 24 h of hypothermic preservation followed by lung transplantation. During five hours of lung reperfusion, functional parameters and biomarkers expression in serum and in bronchoalveolar lavage fluid (BALF) were measured. After five hours of reperfusion, HEMO2life® group led to significant improvement in functional parameters: reduction of graft vascular resistance (p < .05) and increase in graft oxygenation ratio (p < .05). Several ischemia-reperfusion related biomarkers showed positive trends in the HEMO2life® group: expression of HMG B1 in serum tended to be lower in comparison (2.1 ± 0.8 vs. 4.6 ± 1.5) with Perfadex® group, TNF-α and IL-8 in BALF were significantly higher in the two experimental groups compared to control (p < .05). During cold ischemia, expression of HIF1α and histology remained unchanged and similar to control. Supplementation of the Perfadex® solution by an innovative oxygen carrier HEMO2life® during hypothermic static preservation improves early graft function after prolonged cold ischemia in lung transplantation.

Characterizing the early inflammatory contribution of the donor kidney following reperfusion.

Donor kidneys contain a large reservoir of passenger leucocytes that contribute to acute rejection via direct alloantigen presentation and pro-inflammatory cytokine secretion. However, the early contribution of these cells following revascularization has not previously been described. We performed a secondary, high-volume preservation flush following cold storage to characterize the inflammatory contribution of the donor kidney upon reperfusion. Porcine kidneys were retrieved using a protocol analogous to current UK clinical practice. Following 2 h of cold static preservation, kidneys underwent a secondary flush with Ringer's solution. The venous effluent was collected and leucocytes phenotyped via flow cytometry. Inflammatory mediators, including cytokines and cell-free DNA, were then assessed to determine the inflammatory contribution of the donor kidney. Upon reperfusion, a significant population of donor-derived CD45 + leucocytes mobilized from the renal vasculature via the renal vein [mean 4.738 × 10 8 (SD 1.348 × 10 8 )]. Within this population, T cells were dominant, representing >60% of the leucocyte repertoire. Granulocytes, monocytes and natural killer cells were also identified, but in comparatively lower numbers. Significant concentrations of cytokines and cell-free DNA were also eluted upon reperfusion. The donor kidney contains a significant immune load that rapidly mobilizes following reperfusion. Performing a secondary preservation flush prior to implantation may reduce this inflammatory burden via diversion of donor leucocytes and inflammatory mediators from entry into the recipient circulation. This may modulate direct presentation and reduce the inflammatory contribution of the donor kidney following transplantation.

Heart allograft preservation: an arduous journey from the donor to the recipient.

The discrepancy between needs and availability of organs for heart transplantation may be partially reduced by improving the utilization of organs currently deemed unsuitable. Strategies to achieve this goal need optimization of the entire process of organ procurement, transportation, and functional recovery after transplant. In the latest years, several studies reported improvements in organ utilization after appropriate donor management, and management of heart transportation is approaching a new era. In particular, apart from perfecting of traditional cold static preservation techniques, novel technologies now allow continuous heart perfusion prolonging out-of-body times, and prompted to the 'resuscitation' of hearts injured by the warm ischemia of circulatory death donors. The accomplishment of the journey needs appropriate protection of the graft during and after the transplant surgery. This concept is driven by adequate donor-recipient matching and aided by the assist devices that, mimicking organ perfusion machines, may allow graft reconditioning while maintaining recipient's peripheral organ function. The researches reviewed in this article support a significant improvement of the heart preservation during the multifaceted process of procurement, transport, and transplant. Future challenges will be to develop healing of currently unsuitable organs, while keeping the cost of technology within the borders of affordability for healthcare systems.

Effect of Hypothermic Machine Perfusion on the Preservation of Kidneys Donated After Cardiac Death: A Single-Center, Randomized, Controlled Trial.

To assess the application of a hypothermic machine perfusion device (LifePort) in kidney transplantation from donation after cardiac death (DCD) donors, 24 pairs of DCD kidneys were randomly divided into two groups: one of the paired kidneys from the same donor was perfused with the LifePort machine (hypothermic machine perfusion [HMP]), and the contralateral kidney was prepared using common static cold preservation (CCP). The two groups were compared with respect to the incidence of delayed graft function (DGF), level of graft function, and pathological changes in time-zero biopsy specimens. The incidence of DGF was 16.7 and 37.5% in the HMP and CCP groups, respectively; the difference between the two groups was statistically significant (P < 0.05). The incidence of acute rejection was 4.1 (1/24) and 8.3% (2/24) in the HMP and CCP groups, respectively; this difference was not statistically significant (P > 0.05). Forty-eight kidney patients were followed up for 6 months, and the two groups of recipients all survived, yielding a survival rate of 100%. The mean 6-month serum creatinine levels were 98.7 ± 23.6 µmol/L in the HMP group and 105.3 ± 35.1 µmol/L in the CCP group; there was no significant difference between the two groups. HMP can reduce the incidence of DGF in DCD kidneys, and this effect is greater for expanded criteria donors kidneys. HMP can also improve early renal function.

Activation of Fibrinolysis, But Not Coagulation, During End-Ischemic Ex Situ Normothermic Machine Perfusion of Human Donor Livers.

Ex situ normothermic machine perfusion (NMP) can be performed after traditional static cold preservation to assess graft function and viability before transplantation. It is unknown whether this results in activation of coagulation and fibrinolysis, as may occur upon graft reperfusion in vivo. Twelve donor livers declined for transplantation underwent 6 hours of end-ischemic NMP using a heparinized plasma-based perfusion fluid. Concentration of prothrombin fragment F1 + 2 (marker of coagulation activation), D-dimer, plasmin-antiplasmin complex, tissue plasminogen activator and plasminogen activator inhibitor-1 (markers for fibrinolysis) and alanine aminotransferase (ALT) (marker of ischemia-reperfusion [I/R] injury) were measured in perfusion fluid at regular intervals. Liver biopsies were examined for the presence of fibrin, using light microscopy after Maurits, Scarlet and Blue staining. No significant increase in prothrombin F1 + 2 was noted during NMP. D-dimer and plasmin-antiplasmin complex levels increased soon after start of NMP and D-dimer concentrations correlated significantly with levels of tissue plasminogen activator. In livers displaying good function during NMP, perfusate levels of ALT and D-dimers were low (≤3500 ng/mL), whereas significantly higher D-dimer levels (>3500 ng/mL) were in found in livers with poor graft function. Activation of fibrinolysis correlated significantly with the degree of I/R injury, as reflected by ALT levels. End-ischemic ex situ NMP results in activation of fibrinolysis, but not of coagulation. Markers of fibrinolysis activation correlate significantly with markers of I/R injury. High concentrations of D-dimer early after start of NMP can be considered a marker of severe I/R injury and a predictor of poor liver graft function.

Machine Perfusion of Porcine Livers with Oxygen-Carrying Solution Results in Reprogramming of Dynamic Inflammation Networks.

Background: Ex vivo machine perfusion (MP) can better preserve organs for transplantation. We have recently reported on the first application of an MP protocol in which liver allografts were fully oxygenated, under dual pressures and subnormothermic conditions, with a new hemoglobin-based oxygen carrier (HBOC) solution specifically developed for ex vivo utilization. In those studies, MP improved organ function post-operatively and reduced inflammation in porcine livers. Herein, we sought to refine our knowledge regarding the impact of MP by defining dynamic networks of inflammation in both tissue and perfusate.Methods: Porcine liver allografts were preserved either with MP (n = 6) or with cold static preservation (CSP; n = 6), then transplanted orthotopically after 9 h of preservation. Fourteen inflammatory mediators were measured in both tissue and perfusate during liver preservation at multiple time points, and analyzed using Dynamic Bayesian Network (DyBN) inference to define feedback interactions, as well as Dynamic Network Analysis (DyNA) to define the time-dependent development of inflammation networks.Results: Network analyses of tissue and perfusate suggested an NLRP3 inflammasome-regulated response in both treatment groups, driven by the pro-inflammatory cytokine interleukin (IL)-18 and the anti-inflammatory mediator IL-1 receptor antagonist (IL-1RA). Both DyBN and DyNA suggested a reduced role of IL-18 and increased role of IL-1RA with MP, along with increased liver damage with CSP. DyNA also suggested divergent progression of responses over the 9 h preservation time, with CSP leading to a stable pattern of IL-18-induced liver damage and MP leading to a resolution of the pro-inflammatory response. These results were consistent with prior clinical, biochemical, and histological findings after liver transplantation.Conclusion: Our results suggest that analysis of dynamic inflammation networks in the setting of liver preservation may identify novel diagnostic and therapeutic modalities.

The Critical Role of Bioenergetics in Donor Cardiac Allograft Preservation.

The traditional philosophy of ex vivo organ preservation has been to limit metabolic activity by storing organs in hypothermic, static conditions. This methodology cannot provide longevity of hearts for more than 4-6h and is thereby insufficient to expand the number of available organs. Albeit at lower rate, the breakdown of ATP still occurs during hypothermia. Furthermore, cold static preservation does not prevent the permanent damage that occurs upon reperfusion known as ischemia-reperfusion (IR) injury. This damage is caused by increased reactive oxygen species (ROS) production in combination with mitochondrial permeability transition pore (mPTP) opening, highlighting the importance of mitochondria in ischemic storage. There has recently been a major paradigm shift in the field, with emerging research supporting changes in traditional storage approaches. Novel research suggests achieving metabolic homeostasis instead of attempting to limit metabolic activity which reduces IR injury and improves graft preservation. Maintaining high ATP levels and circumventing cold organ storage would be a much more sophisticated standard for organ storage and should be the focus of future research in organ preservation. Given the link between mPTP, Ca2(+), and ROS, managing Ca2(+) influx into the mitochondria during conditioning might be the next critical step towards preventing irreversible IR injury.

Oxygenated hypothermic machine perfusion after static cold storage improves endothelial function of extended criteria donor livers

Background: Lack of oxygen and biomechanical stimulation during static cold storage (SCS) of donor livers compromises endothelial cell function. This study investigated the effect of 2 hours of end-ischemic oxygenated hypothermic machine perfusion (HMP) on endothelial cell function of extended criteria donor (ECD) livers. Method: Sixteen human livers that were declined for transplantation were transported to our center using conventional static cold storage (SCS; 4oC) and subjected to normothermic machine perfusion (NMP) to assess viability and function. Six livers underwent 2 hours oxygenated HMP (12°C) after SCS and prior to NMP. Ten control livers underwent NMP immediately after SCS. Endothelial cell function was assessed by quantification of mRNA expression encoding for transcription factor Krüppel-like-factor-2 (KLF-2), endothelial nitric oxide synthase (eNOS), and thrombomodulin (TM) using real-time PCR. Nitric oxide (NO) production (nitrite/nitrate levels) and release of thrombomodulin (TM) into the perfusion fluid were determined during NMP. Results: In livers that underwent end-ischemic HMP, mRNA expression of KLF-2 (p = 0.04), eNOS (p = 0.03) and TM (p = 0.03) increased significantly during NMP. This response was not observed in the control livers. In parallel, NO levels in the perfusate increased during NMP of livers that first underwent HMP, but not in control livers. Moreover, at the end of NMP cumulative TM release into the perfusate was significantly higher in control livers compared to livers first subjected to HMP (p = 0.03). Conclusion: A short period of 2 hours oxygenated HMP restores endothelial cell function and integrity after conventional static cold preservation and subsequent reoxygenation of ECD livers.

Correction: Gradual Rewarming with Gradual Increase in Pressure during Machine Perfusion after Cold Static Preservation Reduces Kidney Ischemia Reperfusion Injury

Correction: Gradual Rewarming with Gradual Increase in Pressure during Machine Perfusion after Cold Static Preservation Reduces Kidney Ischemia Reperfusion Injury

Effectiveness of pure argon for renal transplant preservation in a preclinical pig model of heterotopic autotransplantation

BackgroundIn kidney transplantation, the conditions of organ preservation following removal influence function recovery. Current static preservation procedures are generally based on immersion in a cold-storage solution used under atmospheric air (approximately 78 kPa N2, 21 kPa O2, 1 kPa Ar). Research on static cold-preservation solutions has stalled, and modifying the gas composition of the storage medium for improving preservation was considered. Organoprotective strategies successfully used noble gases and we addressed here the effects of argon and xenon on graft preservation in an established preclinical pig model of autotransplantation.MethodsThe preservation solution Celsior saturated with pure argon (Argon-Celsior) or xenon (Xenon-Celsior) at atmospheric pressure was tested versus Celsior saturated with atmospheric air (Air-Celsior). The left kidney was removed, and Air-Celsior (n = 8 pigs), Argon-Celsior (n = 8) or Xenon-Celsior (n = 6) was used at 4 °C to flush and store the transplant for 30 h, a duration that induced ischemic injury in our model when Air-Celsior was used. Heterotopic autotransplantation and contralateral nephrectomy were performed. Animals were followed for 21 days.ResultsThe use of Argon-Celsior vs. Air-Celsior: (1) improved function recovery as monitored via creatinine clearance, the fraction of excreted sodium and tubulopathy duration; (2) enabled diuresis recovery 2–3 days earlier; (3) improved survival (7/8 vs. 3/8 pigs survived at postoperative day-21); (4) decreased tubular necrosis, interstitial fibrosis, apoptosis and inflammation, and preserved tissue structures as observed after the natural death/euthanasia; (5) stimulated plasma antioxidant defences during the days following transplantation as shown by monitoring the “reduced ascorbic acid/thiobarbituric acid reactive substances” ratio and Hsp27 expression; (6) limited the inflammatory response as shown by expression of TNF-alpha, IL1-beta and IL6 as observed after the natural death/euthanasia. Conversely, Xenon-Celsior was detrimental, no animal surviving by day-8 in a context where functional recovery, renal tissue properties and the antioxidant and inflammation responses were significantly altered. Thus, the positive effects of argon were not attributable to the noble gases as a group.ConclusionsThe saturation of Celsior with argon improved early functional recovery, graft quality and survival. Manipulating the gas composition of a preservation medium constitutes therefore a promising approach to improve preservation.Electronic supplementary materialThe online version of this article (doi:10.1186/s12967-016-0795-y) contains supplementary material, which is available to authorized users.