Lung Perfusion System Research Articles

Establishment of a Novel Ex Vivo Lung Perfusion System for Rat Lungs After Circulatory Death

Establishment of a Novel Ex Vivo Lung Perfusion System for Rat Lungs After Circulatory Death

Low-Volume Ex Situ Lung Perfusion System for Single Lung Application in a Small Animal Model Enables Optimal Compliance With "Reduction" in 3R Principles of Animal Research.

Ex situ lung perfusion (ESLP) is used for organ reconditioning, repair, and re-evaluation prior to transplantation. Since valid preclinical animal models are required for translationally relevant studies, we developed a 17mL low-volume ESLP for double- and single-lung application that enables cost-effective optimal compliance "reduction" of the 3R principles of animal research. In single-lung mode, ten Fischer344 and Lewis rat lungs were subjected to ESLP and static cold storage using STEEN or PerfadexPlus. Key perfusion parameters, thermal lung imaging, blood gas analysis (BGA), colloid oncotic pressure (COP), lung weight gain, histological work-up, and cytokine analysis were performed. Significant differences between perfusion solutions but not between the rat strains were detected. Most relevant perfusion parameters confirmed valid ESLP with homogeneous lung perfusion, evidenced by uniform lung surface temperature. BGA showed temperature-dependent metabolic activities with differences depending on perfusion solution composition. COP is not decisive for pulmonary oedema and associated weight gain, but possibly rather observed chemokine profile and dextran sensitivity of rats. Histological examination confirmed intact lung architecture without infarcts or hemorrhages due to optimal organ procurement and single-lung application protocol using our in-house-designed ESLP system.

(555) - CRISPR Genome Engineering in Donor Lung During Cyclic EVLP with 10°C Preservation: Usage of TorEx Lung Perfusion System

(555) - CRISPR Genome Engineering in Donor Lung During Cyclic EVLP with 10°C Preservation: Usage of TorEx Lung Perfusion System

Low levels of nitric oxide promotes heme maturation into several hemeproteins and is also therapeutic

Nitric oxide (NO) is a signal molecule and plays a critical role in the regulation of vascular tone, displays anti-platelet and anti-inflammatory properties. While our earlier and current studies found that low NO doses trigger a rapid heme insertion into immature heme-free soluble guanylyl cyclase β subunit (apo-sGCβ), resulting in a mature sGC-αβ heterodimer, more recent evidence suggests that low NO doses can also trigger heme-maturation of hemoglobin and myoglobin. This low NO phenomena was not only limited to sGC and the globins, but was also found to occur in all three nitric oxide synthases (iNOS, nNOS and eNOS) and Myeloperoxidase (MPO). Interestingly high NO doses were inhibitory to heme-insertion for these hemeproteins, suggesting that NO has a dose-dependent dual effect as it can act both ways to induce or inhibit heme-maturation of key hemeproteins. While low NO stimulated heme-insertion of globins required the presence of the NO-sGC-cGMP signal pathway, iNOS heme-maturation also required the presence of an active sGC. These effects of low NO were significantly diminished in the tissues of double (n/eNOS−/−) and triple (n/i/eNOS−/−) NOS knock out mice where lung sGC was found be heme-free and the myoglobin or hemoglobin from the heart/lungs were found be low in heme, suggesting that loss of endogenous NO globally impacts the whole animal and that this impact of low NO is both essential and physiologically relevant for hemeprotein maturation. Effects of low NO were also found to be protective against ischemia reperfusion injury on an ex vivo lung perfusion (EVLP) system prior to lung transplant, which further suggests that low NO levels are also therapeutic.

Determining the role of von Willebrand factor in thrombotic post transplantation complications using ex vivo lung perfusion system

Background and Aims : A major complication of lung transplantation is thrombosis, which may lead to allograft failure. Increased production of procoagulant molecules, such as von Willebrand factor (VWF), is a significant risk factor for thrombus formation. VWF is a pro-coagulant glycoprotein expressed only in endothelial cells and megakaryocytes, which mediates adhesion of platelets to the endothelium/sub-endothelium. External stimuli, including hypoxia can upregulate VWF. Since during organ-transplantation donor organs are under hypoxic conditions, we explored whether this may lead to alterations in VWF expression, and whether ex vivo lung perfusion (EVLP) as an innovative method for organ preservation prior transplantation can moderate the effect of VWF upregulation and its thrombogenic consequences.

Ex Vivo Lung Perfusion with β-Nicotinamide Adenine Dinucleotide (NAD+) Improves Ischemic Lung Function

Ischemia-reperfusion injury compromises short- and long-term outcomes after lung transplantation. The scarce existing data on NAD+ suggest effects on hypoxia-induced vasoconstriction, on reactive oxygen species and on tampering inflammation. We exposed rat lungs to 14 h of cold ischemic storage and perfused them in a rat ex vivo lung perfusion (EVLP) system for 4 h. A control group (n = 6) was compared to groups receiving 100 µM (n = 6) or 200 µM NAD+ (n = 6) in the preservation solution and groups receiving 200 µM (n = 4) or 2000 µM (n = 6) NAD+ every 30 min in the perfusate, starting at 1 h of EVLP. Compared to the control, significant effects were only achieved in the 2000 µM NAD+ group. During the 4 h of EVLP, we monitored higher vascular flow, lower mean pulmonary arterial pressure and increased oxygenation capacity. Tissue inflammation estimated with the myeloperoxidase assay was lower in the 2000 µM NAD+ group. We observed higher levels of anti-inflammatory IL-10, higher anti-inflammatory IL-6/IL-10 ratios and lower levels of pro-inflammatory IL-12 and IL-18 as well as a trend of more anti-inflammatory IFNy in the 2000 µM NAD+ perfusate. In the bronchoalveolar lavage, the pro-inflammatory levels of IL-1α and IL-1β were lower in the 2000 µM NAD+ group. NAD+ administered during EVLP is a promising agent with both anti-inflammatory properties and the ability to improve ischemic lung function.

Development of a cost-effective ex vivo lung perfusion system for lung transplantation in India.

Standard donor lung preservation with cold flush and storage allows up to six hours between retrieval of lungs from the donor and transplantation in the recipient. Ex vivo lung perfusion (EVLP) systems mimic physiological ventilation and perfusion in the donor lungs with potential for prolonged lung preservation and donor lung reconditioning. In this study, it was aimed to perform EVLP on discarded donor lungs using a locally developed EVLP system. Equipment that are routinely used for cardiac surgeries were collected and a functional EVLP system was assembled. This system was used on five pairs of lungs retrieved from brain-dead organ donors. The lungs were ventilated and pulmonary circulation was continuously perfused with a solution containing oxygen and nutrients for four hours. The system was tested without red blood cells (RBCs) added to the solution (acellular group; n=3; A1, A2 and A3) and also with RBCs added to the solution (cellular group; n=2; C1 and C2). The EVLP system was successfully used in four (A1, A2, A3 and C2) of the five lung pairs. Mechanical and gas exchange functions of the lungs were preserved in these lung pairs. One lung pair (C1) worsened and developed pulmonary oedema. Histopathological examination of all five lung pairs was satisfactory at the end of the procedure. Major challenges faced were leakage of solution from the system and obstruction to drainage of RBCs containing solution from the lungs. The results of the present study suggest that, it is possible to maintain the lungs retrieved for transplantation in a physiological condition using a locally prepared EVLP system and a solution without RBCs.

Inhaled sphingosine has no adverse side effects in isolated ventilated and perfused pig lungs

Ex-vivo lung perfusion (EVLP) systems like XVIVO are more and more common in the setting of lung transplantation, since marginal donor-lungs can easily be subjected to a performance test or be treated with corticosteroids or antibiotics in high dose regimes. Donor lungs are frequently positive in bronchoalveolar lavage (BAL) bacterial cultures (46–89%) which leads to a donor-to-recipient transmission and after a higher risk of lung infection with reduced posttransplant outcome. We have previously shown that sphingosine very efficiently kills a variety of pathogens, including Pseudomonas aeruginosa, Staphylococcus aureus and epidermidis, Escherichia coli or Haemophilus influenzae. Thus, sphingosine could be a new treatment option with broadspectrum antiinfective potential, which may improve outcome after lung transplantation when administered prior to lung re-implantation. Here, we tested whether sphingosine has any adverse effects in the respiratory tract when applied into isolated ventilated and perfused lungs. A 4-h EVLP run using minipig lungs was performed. Functional parameters as well as perfusate measurements where obtained. Biopsies were obtained 30 min and 150 min after inhalation of sphingosine. Tissue samples were fixed in paraformaldehyde, embedded in paraffin and sectioned. Hemalaun, TUNEL as well as stainings with Cy3-coupled anti-sphingosine or anti-ceramide antibodies were implemented. We demonstrate that tube-inhalation of sphingosine into ex-vivo perfused and ventilated minipig lungs results in increased levels of sphingosine in the luminal membrane of bronchi and the trachea without morphological side effects up to very high doses of sphingosine. Sphingosine also did not affect functional lung performance. In summary, the inhalation of sphingosine results in an increase of sphingosine concentrations in the luminal plasma membrane of tracheal and bronchial epithelial cells. The inhalation has no local side effects in ex-vivo perfused and ventilated minipig lungs.

Isolated Lung Perfusion System in the Rabbit Model.

The isolated lung perfusion system has been widely used in pulmonary research, contributing to elucidate the lungs' inner workings, both micro and macroscopically. This technique is useful in the characterization of pulmonary physiology and pathology by measuring metabolic activities and respiratory functions, including interactions between circulatory substances and the effects of inhaled or perfused substances, as in drug testing. While in vitro methods involve the slicing and culturing of tissues, the isolated ex vivo lung perfusion system allows to work with a complete functional organ making possible the study of a continuous physiological function while recreating ventilation and perfusion. However, it should be noted that the effects of the absence of central innervation and lymphatic drainage still have to be fully assessed. This protocol aims to describe the assembly of the isolated lung apparatus, followed by the surgical extraction and cannulation of lungs and heart from experimental lab animals, as well as to display the perfusion technique and signal processing of data. The average viability of the isolated lung ranges between 5-8 h; during this period, the pulmonary capillary permeability increases, causing edema and lung injury. The functionality of preserved pulmonary tissue is measured by the capillary filtration coefficient (Kfc), used to determine the extent of pulmonary edema through time.

Isolated Lung Perfusion System in the Rabbit Model

The isolated rabbit lung preparation is a gold standard tool in pulmonary research. This publication aims to describe the technique as developed for the study of physiological and pathological mechanisms involved in airway reactivity, lung preservation, and preclinical research in lung transplantation and pulmonary edema.

Ischemia-Reperfusion Injury in Lung Transplantation.

Lung transplantation has been established worldwide as the last treatment for end-stage respiratory failure. However, ischemia–reperfusion injury (IRI) inevitably occurs after lung transplantation. The most severe form of IRI leads to primary graft failure, which is an important cause of morbidity and mortality after lung transplantation. IRI may also induce rejection, which is the main cause of mortality in recipients. Despite advances in donor management and graft preservation, most donor grafts are still unsuitable for transplantation. Although the pulmonary endothelium is the primary target site of IRI, the pathophysiology of lung IRI remains incompletely understood. It is essential to understand the mechanism of pulmonary IRI to improve the outcomes of lung transplantation. Therefore, we reviewed the state-of-the-art in the management of pulmonary IRI after lung transplantation. Recently, the ex vivo lung perfusion (EVLP) system has been clinically introduced worldwide. Various promising therapeutic strategies for the protection of the endothelium against IRI, including EVLP, inhalation therapy with therapeutic gases and substances, fibrinolytic treatment, and mesenchymal stromal cell therapy, are awaiting clinical application. We herein review the latest advances in the field of pulmonary IRI in lung transplantation.

Nanotraps for the containment and clearance of SARS-CoV-2

SARS-CoV-2 enters host cells through its viral spike protein binding to angiotensin-converting enzyme 2 (ACE2) receptors on the host cells. Here, we show that functionalized nanoparticles, termed “Nanotraps,” completely inhibited SARS-CoV-2 infection by blocking the interaction between the spike protein of SARS-CoV-2 and the ACE2 of host cells. The liposomal-based Nanotrap surfaces were functionalized with either recombinant ACE2 proteins or anti-SARS-CoV-2 neutralizing antibodies and phagocytosis-specific phosphatidylserines. The Nanotraps effectively captured SARS-CoV-2 and completely blocked SARS-CoV-2 infection to ACE2-expressing human cell lines and primary lung cells; the phosphatidylserine triggered subsequent phagocytosis of the virus-bound, biodegradable Nanotraps by macrophages, leading to the clearance of pseudotyped and authentic virus in vitro. Furthermore, the Nanotraps demonstrated an excellent biosafety profile in vitro and in vivo. Finally, the Nanotraps inhibited pseudotyped SARS-CoV-2 infection in live human lungs in an ex vivo lung perfusion system. In summary, Nanotraps represent a new nanomedicine for the inhibition of SARS-CoV-2 infection.

Advances in bioreactors for lung bioengineering: From scalable cell culture to tissue growth monitoring.

Lung bioengineering has emerged to resolve the current lung transplantation limitations and risks, including the shortage of donor organs and the high rejection rate of transplanted lungs. One of the most critical elements of lung bioengineering is bioreactors. Bioreactors with different applications have been developed in the last decade for lung bioengineering approaches, aiming to produce functional reproducible tissue constructs. Here, the current status and advances made in the development and application of bioreactors for bioengineering lungs are comprehensively reviewed. First, bioreactor design criteria are explained, followed by a discussion on using bioreactors as a culture system for scalable expansion and proliferation of lung cells, such as producing epithelial cells from induced pluripotent stem cells (iPSCs). Next, bioreactor systems facilitating and improving decellularization and recellularization of lung tissues are discussed, highlighting the studies that developed bioreactors for producing engineered human-sized lungs. Then, monitoring bioreactors are reviewed, showing their ability to evaluate and optimize the culture conditions for maturing engineered lung tissues, followed by an explanation on the ability of ex vivo lung perfusion systems for reconditioning the lungs before transplantation. After that, lung cancer studies simplified by bioreactors are discussed, showing the potentials of bioreactors in lung disease modeling. Finally, other platforms with the potential of facilitating lung bioengineering are described, including the in vivo bioreactors and lung-on-a-chip models. In the end, concluding remarks and future directions are put forward to accelerate lung bioengineering using bioreactors.

Waste Not, Want Not: Decreasing Wastage through the Utilization of Thermal Controlled Technology with Ex Vivo Lung Perfusion

<h3>Purpose</h3> The Organ Care System (OCS) (TransMedics, Andover, MA) is one type of revolutionary ex vivo organ perfusion technology that expands the organ retrieval range while limiting ischemic time significantly. OCS Lung is the only FDA-approved, portable, normothermic lung perfusion system for standard and expanded criteria donor lungs. Current ex vivo lung perfusion (EVLP) systems use a variety of perfusates. OCS Lung uses packed red blood cells (pRBC) diluted in the OCS Lung solution. We report the ability to reduce blood waste for up to 12 hours using a thermal packaging solution in conjunction with an EVLP system. <h3>Methods</h3> We performed a retrospective analysis of all OCS Lung recoveries at our hospital that used banked blood from May 2019 to May 2020. Three units of leukocyte-reduced, ABO compatible, cross-matched pRBC are transported for EVLP perfusate. These pRBC units are CMV seronegative when indicated (both recipient and donor CMV seronegative). During the first six months, units were stored using the Coleman Performance Wheeled Cooler (Coleman Company, Chicago, IL) that has been validated to maintain a temperature range of 1° to 6°C for 4 hours. During the following six months, units were stored using a Crēdo ProMed Cooler (Pelican BioThermal, Plymouth, MN) that has been validated to maintain a temperature range of 1° to 6°C for 12 to 72 hours. <h3>Results</h3> We provide documentation of unit disposition and duration in the respective cooler as well as the impact expanded organ retrieval range has on unit viability. (Table 1-3). <h3>Conclusion</h3> The use of an advanced thermal packaging solution facilitates the proper storage temperature of pRBC for the extended period of time required for organ retrieval. This finding represents a significant advancement in the storage of blood perfusate used for donor lung preservation. The ability to eliminate blood wastage could result in an average annual saving of $3,000 and warrants further multicenter investigation.

MG53 as a Novel Therapeutic Protein to Treat Acute Lung Injury.

Lung injury has several inciting etiologies ranging from trauma (contusion and hemorrhage) to ischemia reperfusion injury. Reflective of the injury, tissue and cellular injury increases proportionally with the injury stress and is an area of potential intervention to mitigate the injury. This study aims to evaluate the therapeutic benefits of recombinant human MG53 (rhMG53) protein in porcine models of acute lung injury (ALI). We utilized live cell imaging to monitor the movement of MG53 in cultured human bronchial epithelial cells following mechanical injury. The in vivo efficacy of rhMG53 was evaluated in a porcine model of hemorrhagic shock/contusive lung injury. Varying doses of rhMG53 (0, 0.2, or 1 mg/kg) were administered intravenously to pigs after induction of hemorrhagic shock/contusive induced ALI. Ex vivo lung perfusion system enabled assessment of the isolated porcine lung after a warm ischemic induced injury with rhMG53 supplementation in the perfusate (1 mg/mL). MG53-mediated cell membrane repair is preserved in human bronchial epithelial cells. rhMG53 mitigates lung injury in the porcine model of combined hemorrhagic shock/contusive lung injury. Ex vivo lung perfusion administration of rhMG53 reduces warm ischemia-induced injury to the isolated porcine lung. MG53 is an endogenous protein that circulates in the bloodstream. Therapeutic treatment with exogenous rhMG53 may be part of a strategy to restore (partially or completely) structural morphology and/or functional lung integrity. Systemic administration of rhMG53 constitutes a potential effective therapeutic means to combat ALI.

Organ Care System Lung resulted in lower apoptosis and iNOS expression in donor lungs.

Ischemia-reperfusion (IR) injury after lung transplantation is still today an important complication in up to 25% of patients. The Organ Care System (OCS) Lung, an advanced normothermic ex vivo lung perfusion system, was found to be effective in reducing primary graft dysfunction compared to standard organ care (SOC) but studies on tissue/molecular pathways that could explain these more effective clinical results are lacking. This observational longitudinal study aimed to investigate IR injury in 68 tissue specimens collected before and after reperfusion from 17 OCS and 17 SOC preserved donor lungs. Several tissue analyses including apoptosis evaluation and inducible nitric oxide synthase (iNOS) expression (by immunohistochemistry and real-time reverse transcriptase-polymerase chain reaction) were performed. Lower iNOS expression and apoptotic index were distinctive of OCS preserved tissues at pre- and post-reperfusion times, independently from potential confounding factors. Moreover, OCS recipients had lower acute cellular rejection at the first 6-month follow-up. In conclusion, IR injury, in terms of apoptosis and iNOS expression, was less frequent in OCS- than in SOC-preserved lungs, which could eventually explain a better clinical outcome. Further studies are needed to validate our data and determine the role of iNOS expression as a predictive biomarker of the complex IR injury mechanism.

Temperature Controlled and Monitored Ex Vivo Lung Perfusion System for Research and Training Purposes

Abstract Ex vivo lung perfusion (EVLP) is a preservation method for donor lungs, which keep lungs viable in a physiological environment outside of a body for a short period of time. EVLP is established clinically for lung transplantation. Experimental applications for EVLP are e.g. lung cancer research or medical device development and testing. For preservation, a lung is ventilated artificially in an organ chamber and perfused antegrade through the pulmonary artery. Here we introduce a thermoregulation system for an experimental EVLP system to be used for translational research approaches as well as for training medical staff. To implement physiological culture conditions that are a prerequisite for lung preservation and tissue homeostasis, a thermoregulation is needed to rewarm the explanted lung tissue (storage temperature 4°C). Technically, the EVLP system must be thermally insulated, so loss of caloric is avoided. For monitoring, temperature sensors are integrated within the lung, in the organ chamber and in the afferent perfusate tube, whereby the measured values determine the thermoregulation. Initial tests using thermal packs (cooled to 4-6°C) placed on a heating mat, as a part of the perfusion circuit, showed that the perfusate temperature falls to 34°C, but restores after approximately 60 minutes (36.5°C), whereby the thermal pack is warmed. With this setup longer perfusion times should be obtained rather than without thermoregulation due to normothermic perfusion of the lung.

A closer look at donor lung expansion with different static ex vivo lung perfusion (EVLP) systems – invited commentary

A closer look at donor lung expansion with different static ex vivo lung perfusion (EVLP) systems – invited commentary

Multiparametric MRI for organ quality assessment in a porcine Ex-Vivo lung perfusion system.

IntroductionEx-vivo lung perfusion (EVLP) is an emerging technique promising an expansion of the donor pool and improvements in the outcome after lung transplantation. Reliable biomarkers for local assessment of organ function in the EVLP system are intensely sought after. This study aims to evaluate the feasibility of multiparametric functional magnetic resonance imaging (fMRI) in an EVLP system in a porcine aspiration model.Material and methodsSeven female pigs were anesthetized and gastric juice was instilled in the right lower lobe bronchus to simulate aspiration. Left lungs served as control. Lungs were removed and installed in a modified EVLP system. In the 12-hour EVLP run three sequential MRI scans were performed. Oxygen-washout time, Fourier Decomposition derived ventilation and perfusion, and dynamic contrast enhanced imaging derived perfusion were calculated. PaO2:FiO2 ratio was determined and correlated. End-point histology and computed tomography served as control.ResultsAll animals completed the protocol. MRI structural images showed infiltrates in lungs after aspiration comparable to CT scans. Ventilation was significantly (p = 0.016) reduced while perfusion was increased (p = 0.016) in lungs after aspiration. Non-contrast dependent Fourier decomposition perfusion showed good correlation (R2 = 0.67) to dynamic contrast enhanced derived perfusion. Oxygen washout time was significantly increased (p = 0.016) in lungs after aspiration and showed a correlation with the PaO2:FiO2 ratio (R2 = 0.54).ConclusionMultiparametric fMRI for local assessment of organ function is feasible in EVLP and detects alterations in lung function following aspiration with correlation to clinical parameters. fMRI may improve organ assessment in ex-vivo perfusion systems, leading to a better selection of segments suitable for transplant.

The start of the Hungarian lung transplantation program and the first results

The first lung transplantation in Hungary was performed on 12th of December, 2015. It was a joint effort of the National Institute of Oncology and the Semmelweis University. Hereby we summarise the results and experiences from the first three years. Until August, 2018, 55 lung transplantations were performed in Hungary. This was a retrospective analysis. All patients were listed according to the recommendation of the Lung Transplantation Committee. All implanted lungs have been procured from brain dead donors. Postoperative treatment and rehabilitation of the patients were continued at the Semmelweis University. Between 12. 12. 2015 and 31. 07. 2018, our team performed 76 organ retrievals: out of 45 Hungarian offers, 23 came from Eurotransplant countries and 8 outside of the Eurotransplant region. From these donations, 54 double and 1 single side transplantations were successfully performed. The surgical approach was single side thoracotomy (n = 1), bilateral thoracotomy (n = 1) and in the majority of the cases clamshell incision (n = 53). For the intraoperative veno-arterial extracorporeal membrane oxygenation support was used. The extracorporeal membrane oxygenation support had to be prolonged in 3 patients into the early postoperative period, two other recipients were bridged to transplant with extracorporeal membrane oxygenation. In the same time period, one combined lung-kidney transplantation was also performed. The distribution of recipients according to the underlying disease was: chronic obstructive pulmonary disease (n = 28); idiopathic pulmonary fibrosis (n = 8); cystic fibrosis (n = 12); primary pulmonary hypertension (n = 2); hystiocytosis-X (n = 1); bronchiectasis (n = 2); lymphangioleiomyomatosis (n = 1); and re-transplantation following bronchiolitis obliterans syndrome (n = 1), respectively. The mean age of recipients was 47.5 ± 15.18 years. The youngest recipient was 13 years old. We unfortunately lost 12 patients on our waiting list. The mean intensive care unit stay was 24.6 ± 18.18 days. Two patients were lost in the early postoperative phase. Tracheostomy was necessary in 13 cases due to the need of prolonged ventilation. 1-year survival of the recipients was 82.96% (until 31. 07. 2018). When looking at the first three years of the program, the case numbers elevated quickly throughout the years which is rather unique when compared to other centres in their starting period. Perioperative mortality and morbidity is comparable with high-volume lung transplantation centres. In the future we would like to increase the number of patients on the waiting list, thus increasing the total number of transplantations performed, and we are also planning to implement the use of the ex vivo lung perfusion system (EVLP) in our program. Orv Hetil. 2018; 159(46): 1859-1868.