Improved Lung Preservation Research Articles

Heparanase inhibition preserves the endothelial glycocalyx in lung grafts and improves lung preservation and transplant outcomes

The endothelial glycocalyx (eGC) is considered a key regulator of several mechanisms that prevent vascular injury and disease. Degradation of this macromolecular layer may be associated with post-transplant graft dysfunction. In this study, we aimed to demonstrate the benefits of eGC protection via heparanase inhibition on graft quality. We established rat models of lung grafts with damaged or preserved eGC using ischemic insult and transplanted the grafts into recipients. Lung grafts were also subjected to normothermic ex vivo lung perfusion for detailed assessment under isolated conditions. Physiologic parameters and eGC-associated cellular events were assessed in grafts before and after reperfusion. Structurally degraded eGC and highly activated heparanase were confirmed in lungs with ischemic insult. After transplant, lungs with damaged eGC exhibited impaired graft function, inflammation, edema, and inflammatory cell migration. Increased eGC shedding was evident in the lungs after reperfusion both in vivo and ex vivo. These reperfusion-related deficiencies were significantly attenuated in lungs with preserved eGC following heparanase inhibition. Our studies demonstrated that eGC plays a key role in maintaining lung graft quality and function. Heparanase inhibition may serve as a potential therapeutic to preserve eGC integrity, leading to improved post-transplant outcomes.

Immune-Mechanistic Insights into Improved Lung Preservation using the Organ Care System in a Porcine Transplantation Model in Comparison to the INSPIRE Trial

Background Portable ex vivo lung perfusion (EVLP) is a promising alternative to cold static storage for graft preservation in lung transplantation. In the clinical INSPIRE trial, lung preservation with the organ care system (OCS) resulted in reduced rates of early severe primary graft dysfunction. Here, we investigate the mechanism of improved preservation in the OCS and immunological changes in a porcine lung transplant model in order to compare the immunological changes with the findings of the INSPIRE tiral . Methods A total of 12 porcine donor lungs were retrieved after standard cold flush with LPD solution. Six lungs were preserved at normothermia in the OCS for 6 hours (OCS group) and another six lungs were preserved on ice for 6 h (standard of care, SOC group) and left lungs were transplanted into allogeneic porcine recipients. Six additional animals received sham surgery. All pigs were observed for another 6 hours after clamping the contralateral lung or sham surgery. In addition to hemodynamic and respiratory parameters, we investigated cytokines in recipient plasma and bronchoalveolar lavage (BAL) fluid and perfusates. Results In the SOC group, two animals died upon clamping of the contralateral lung due to right heart failure. All pigs in the sham group and in the OCS group survived the observation period of 6 hours. Oxygenation (PaO2/FiO2) at the end of the postoperative observation period was significantly better in the OCS group as opposed to the SOC or sham groups (PaO2/FiO2 after 6 hrs: 231.8±21.3 vs. 129.5±41.1 vs. 154.6±30.8; p<0.05). Lung compliances and pulmonary vascular resistance was higher in the OCS group compared with the SOC and sham groups. In BAL of OCS recipients at 6 h, significantly lower levels of IL-6 (p=0.04), IL-1a (p=0.04), IL-1RA (p=0.03), IL-12 (p=0.03), IL-18 (p=0.03) and IFN-g (p=0.04) were observed compared to SOC recipients. The lower plasma levels (IL-6, IL-1a, IL-18) of the OCS groups at 0.5, 2, 6h did not reach significance. In perfusates of OCS lungs, significantly higher cytokine levels were detected compared to perfusated of SOC lungs, especially the antagonist IL-1RA. Conclusion In an acute porcine lung transplantation model, arterial oxygenation was improved in recipients of lungs preserved in normothermia in the OCS compared to recipients of lungs stored on ice. Moreover, the inflammatory response in BAL and blood was significantly reduced and antagonists like IL-1RA were elevated, confirming previous findings in INSPIRE trial patients.

Cytokine Dynamics Insights into Improved Lung Preservation Using the Organ Care System in a Porcine Transplantation Model in Comparison to the INSPIRE Trial

Cytokine Dynamics Insights into Improved Lung Preservation Using the Organ Care System in a Porcine Transplantation Model in Comparison to the INSPIRE Trial

Improved Lung Preservation in the Organ Care System in a Porcine Transplantation Setting Modelled After the INSPIRE Trial Triggers a Proregulatory T Cell Phenotype

Improved Lung Preservation in the Organ Care System in a Porcine Transplantation Setting Modelled After the INSPIRE Trial Triggers a Proregulatory T Cell Phenotype

Targeting Glucose Metabolism During Ex vivo Lung Perfusion Improves Lung Preservation and Post Transplant Lung Function

Higher glucose consumption represents a unique feature of lung allografts with potentially detrimental qualities; however, its metrics as well as relevance remain to be elucidated. In this study, we hypothesized that preconditioning with an inhibitor of glycolysis may improve the quality of lung allografts through better control of cellular metabolism.

Targeting Circulating Leukocytes and Pyroptosis During Ex Vivo Lung Perfusion Improves Lung Preservation.

The role of the circulating leukocytes in lungs and their relationship with circulating proinflammatory cytokines during ischemia-reperfusion injury is not well understood. Using ex vivo lung perfusion (EVLP) to investigate the pathophysiology of isolated lungs, we aimed to identify a therapeutic target to optimize lung preservation leading to successful lung transplantation. Rat heart-lung blocks were placed on EVLP for 4 hours with or without a leukocyte-depleting filter (LF). After EVLP, lung grafts were transplanted, and posttransplant outcomes were compared. Lung function was significantly better in lung grafts on EVLP with a LF than in lungs on EVLP without a LF. The interleukin (IL)-6 levels in the lung grafts and EVLP perfusate were also significantly lower after EVLP with a LF. Interestingly, IL-6 levels in the perfusate did not increase after the lungs were removed from the EVLP circuit, indicating that the cells trapped by the LF were not secreting IL-6. The trapped cells were analyzed with flow cytometry to detect apoptosis and pyroptosis; 26% were pyroptotic (Caspase-1-positive). After transplantation, there was better graft function and less inflammatory response if a LF was used or a caspase-1 inhibitor was administered during EVLP. Our data demonstrated that circulating leukocytes derived from donor lungs, and not circulating proinflammatory cytokines substantially impaired the quality of lung grafts through caspase-1-induced pyroptotic cell death during EVLP. Removing these cells with a LF and/or inhibiting pyroptosis of the cells can be a new therapeutic approach leading to long-term success after lung transplantation.

592 Improved Lung Preservation by Increasing Flush Temperature in Rats

Several studies have indicated that application of higher flush or storage temperatures result in better lung preservation than the commonly used flush at 4°C and storage on melting ice. The aim of this study is to investigate the optimal combination of flush and storage temperature in a rat lung transplant model.

Improved lung preservation relates to an increase in tubular myelin-associated surfactant protein A

BackgroundDeclining levels of surfactant protein A (SP-A) after lung transplantation are suggested to indicate progression of ischemia/reperfusion (IR) injury. We hypothesized that the previously described preservation-dependent improvement of alveolar surfactant integrity after IR was associated with alterations in intraalveolar SP-A levels.MethodsUsing immuno electron microscopy and design-based stereology, amount and distribution of SP-A, and of intracellular surfactant phospholipids (lamellar bodies) as well as infiltration by polymorphonuclear leukocytes (PMNs) and alveolar macrophages were evaluated in rat lungs after IR and preservation with EuroCollins or Celsior.ResultsAfter IR, labelling of tubular myelin for intraalveolar SP-A was significantly increased. In lungs preserved with EuroCollins, the total amount of intracellular surfactant phospholipid was reduced, and infiltration by PMNs and alveolar macrophages was significantly increased. With Celsior no changes in infiltration or intracellular surfactant phospholipid amount occurred. Here, an increase in the number of lamellar bodies per cell was associated with a shift towards smaller lamellar bodies. This accounts for preservation-dependent changes in the balance between surfactant phospholipid secretion and synthesis as well as in inflammatory cell infiltration.ConclusionWe suggest that enhanced release of surfactant phospholipids and SP-A represents an early protective response that compensates in part for the inactivation of intraalveolar surfactant in the early phase of IR injury. This beneficial effect can be supported by adequate lung preservation, as e.g. with Celsior, maintaining surfactant integrity and reducing inflammation, either directly (via antioxidants) or indirectly (via improved surfactant integrity).

Plasmolemmal potassium gradient does not affect lung protection by an ATP-regulated potassium channel opener.

We have previously shown that metabolic arrest induced with ATP-regulated potassium channel openers (PCOs) can improve lung preservation by adding Aprikalim (a PCO, Rhone-Poulene Roher) to modified Euro-Collins solution for pulmonary artery flush. Because the membrane hyperpolarizing effects of a PCO potentially competes with the depolarizing effects of a hyperkalemic solution, this study evaluated the effects of the potassium gradient on PCO-mediated lung protection. Twenty rabbits underwent lung protection in four groups. Group 1 underwent harvest and reperfusion as a "no ischemia" control. Groups 2, 3, and 4 underwent harvest followed by 18 hours of cold ischemic storage before reperfusion. Groups 1 and 4 received Euro Collins as the pulmonary flush at induction of ischemia. Group 2 received Euro Collins plus Aprikalim (100 microM); and group 3 received lactated Ringer's plus Aprikalim. After ischemic storage, the lungs were reperfused with autologous blood for 2 hours. Every 30 minutes, the lungs were given a 10-minute 100% fractional inspired oxygen (F(i)O(2)) challenge to measure maximal gas exchange as an indication of graft function. Repeated measures ANOVA showed Aprikalim improved graft function after 18 hours of cold ischemia (p < 0.0001). No significant differences were found when Aprikalim was used in either Euro-Collins (group 2) or lactated Ringer's (group 3) solution. The ability of the PCO Aprikalim to preserve gas exchange in a model of hypothermic pulmonary ischemia-reperfusion injury was not affected by the plasmolemmal potassium gradient. This is consistent with recent findings in myocardial protection studies that the protective effects of PCOs may be intracellular.

Timing of nitric oxide donor supplementation determines endothelin-1 regulation and quality of lung preservation for transplantation.

Nitroglycerin (NTG) given to donor lungs improves lung preservation for transplantation, but the mechanism(s) underlying this therapeutic benefit remain incompletely understood. Furthermore, it is not known whether the therapeutic window of opportunity for NTG administration is temporally-restricted. Because endothelin-1 (ET-1), a potent vasoconstrictor, and nitric oxide (NO) are reciprocally regulated in vitro, we hypothesized that early administration of the NO donor NTG may suppress ET-1 and thereby improve lung preservation. Using an isogeneic rat left lung transplantation model, four groups were studied (n = 12 transplant/group): (1) NTG given during flush/ preservation (Early NTG); (2) NTG given in the ex vivo flush (Late NTG); (3) No NTG; and (4) a nonselective ET-receptor antagonist (PD156252) given during flush/preservation. Early NTG decreased vascular tone in lung grafts measured ex vivo as well as in vivo following lung transplantation, and resulted in improved survival (100%) and gas exchange (pO2 209 +/- 19 mm Hg) compared with Late (17%, 62 +/- 16 mm Hg) or No NTG (25%, 59 +/- 9 mm Hg) (P < 0.05 for Early NTG versus all other groups for both survival and pO2). PD156252 was associated with an intermediate level of survival (50%) and function (104 +/- 23 mm Hg). Transplanted lung graft ET-1 mRNA, measured by Northern blotting and in situ hybridization, and protein, measured by Western blotting and immunohistochemistry, were suppressed only with Early NTG (P < 0.05 versus all other groups). Post-transplantation benefits of NTG are restricted to lung grafts which received NTG during the early harvest and immersion periods, and are coincident with suppression of graft ET-1 expression. When viewed in the context of improved graft survival and function with ET-1 receptor blockade, these data suggest that early administration of NTG to donor lungs improves primary graft function, in part, by suppressing graft ET-1 expression.

Cardiac ischemic preconditioning improves lung preservation in valve replacement operations

Background. Previous work has shown that cardiac ischemic preconditioning reduces cardiac reperfusion injury. We investigated whether cardiac ischemic preconditioning can improve lung preservation in patients who undergo valve replacement. Methods. Forty patients with rheumatic heart disease requiring valve replacement were randomly divided into two groups. Twenty patients received two cycles of 3 minutes of aortic cross-clamping and 2 minutes of reperfusion before cardioplegic arrest (group IP), and 20 patients underwent 10 minutes of cardiopulmonary bypass (group C, control group). Blood samples from the pulmonary vein were collected to measure levels of polymorphonuclear leukocytes, superoxide dismutase, malonedialdehyde, and thromboxane B 2, and arterial oxygen tension. Blood samples from the coronary sinus were used to measure calcitonin gene–related peptide values. Hemodynamic data were recorded by a pulmonary artery Swan-Ganz catheter. Lung tissue was collected after 1 hour of reperfusion to evaluate morphology. Clinical outcome data were recorded. Results. In group C (cardiopulmonary bypass and cardioplegic arrest), the levels of polymorphonuclear leukocytes, thromboxane B 2, malonedialdehyde, and calcitonin gene–related peptide were increased after 1 hour of reperfusion, whereas the value for superoxide dismutase was decreased. In group IP, preconditioning attenuated the increase in polymorphonuclear leukocytes, thromboxane B 2, and malonedialdehyde ( p < 0.05) and increased superoxide dismutase and calcitonin gene–related peptide levels ( p < 0.05). Preconditioning also increased arterial oxygen tension and cardiac index compared with controls ( p < 0.05) and decreased mean pulmonary artery pressure and pulmonary vascular resistance index ( p < 0.05). Histologic findings showed less lung injury and a lower polymorphonuclear leukocyte count in group IP than in group C ( p < 0.05). Group IP had fewer postoperative pulmonary complications and a shorter intubation time. Conclusions. Cardiac ischemic preconditioning improves lung preservation in patients having valve replacement. The mechanism may be that cardiac ischemic preconditioning reduces the accumulation of polymorphonuclear leukocytes in lung tissue and decreases the formation of oxygen free radicals.Key Words: Ischemic preconditioning; lung injury; open heart surgery; calcitonin gene–related peptide.

Significance of cyclic adenosine monophosphate and nitroglycerin in ET-Kyoto solution for lung preservation

Background. We previously demonstrated that the supplement of both dibutyryl cyclic adenosine monophosphate (db-cAMP) and nitroglycerin to the conventional ET-Kyoto solution improved lung preservation significantly. However, the significance of each component in lung preservation remained unclear. We examined the efficacy of the two components on lung preservation in the current study.Methods. Rat lung grafts (eight per group) were studied in an isolated lung perfusion model. Group 1 grafts were flushed and preserved with ET-Kyoto solution containing 2 mmol/L of db-cAMP. Group 2 grafts were flushed and preserved with ET-Kyoto solution containing 100 mg/L of nitroglycerin. In group 3, the grafts were flushed and preserved with ET-Kyoto solution containing neither db-cAMP nor nitroglycerin as control group. After 4-hour cold storage, the lung grafts were reperfused for 50 minutes.Results. The lung grafts in groups 1 and 2 showed significantly better lung function after reperfusion than those in group 3 with regard to arterial oxygen tension, shunt fraction, peak inspiratory airway pressure, mean pulmonary arterial pressure, and pulmonary vascular resistance. The supplementation of db-cAMP improved especially the pulmonary arterial pressure and pulmonary vascular resistance, while the supplementation of nitroglycerin improved especially the oxygenation and airway pressure of the grafts.Conclusions. Both of db-cAMP and nitroglycerin had beneficial effects on lung preservation and are essential to the ET-Kyoto solution. There was a difference between the two components in the effects on preserved lungs.

Identification of Optimal Conditions for Lung Graft Storage With Euro-Collins Solution by Use of a Rat Orthotopic Lung Transplant Model

Background —Lung preservation disrupts normal vascular homeostasis, resulting in increased permeability, vasoconstriction, and endothelial cell adhesion for neutrophils. We hypothesized that a storage strategy that best preserves post–lung transplantation (LTX) vascular homeostasis might be organ and species specific. Because of the potential utility of a rat LTX model for developing improved lung preservation strategies, we have attempted to identify the optimal physical conditions for rat lung graft storage. Methods and Results —Conditions that were tested included harvest inflation pressure (0, 10, or 20 mm Hg), inflation gas composition (100% N 2 , room air, or 100% O 2 ), and storage temperature (4°, 10°, or 15°C). Modified Euro-Collins solution served as the base preservation solution for all experiments, with a preservation duration of 4 to 6 hours. Arterial oxygenation (Pa o 2 , mm Hg), pulmonary vascular resistance (mm Hg/mL per minute), recipient survival (%), and graft neutrophil infiltration (ΔAbs 460 nm /min) were measured 30 minutes after transplantation of the left lung and exclusion of the right lung from the circulation. All tested conditions significantly affect post-LTX vascular homeostasis. Inflation at 10 mm Hg pressure preserved lungs significantly better than did other pressures. There was a tendency for room air to improve all measured variables compared with 100% N 2 or 100% O 2 and a significant improvement in recipient survival with room air storage. Of the 3 storage temperatures investigated, 10°C storage provided the best preservation in terms of Pa o 2 , graft neutrophil infiltration, and survival. Conclusions —We conclude that storage at 10°C, 10 mm Hg inflation pressure, with room air establishes optimal lung storage conditions with Euro-Collins solution in this rat LTX model. These data suggest that these conditions should be used to evaluate new and potentially improved preservation strategies.

Identification of optimal conditions for lung graft storage with Euro-Collins solution by use of a rat orthotopic lung transplant model.

Lung preservation disrupts normal vascular homeostasis, resulting in increased permeability, vasoconstriction, and endothelial cell adhesion for neutrophils. We hypothesized that a storage strategy that best preserves post-lung transplantation (LTX) vascular homeostasis might be organ and species specific. Because of the potential utility of a rat LTX model for developing improved lung preservation strategies, we have attempted to identify the optimal physical conditions for rat lung graft storage. Conditions that were tested included harvest inflation pressure (0, 10, or 20 mm Hg), inflation gas composition (100% N(2), room air, or 100% O(2)), and storage temperature (4 degrees, 10 degrees, or 15 degrees C). Modified Euro-Collins solution served as the base preservation solution for all experiments, with a preservation duration of 4 to 6 hours. Arterial oxygenation (PaO(2), mm Hg), pulmonary vascular resistance (mm Hg/mL per minute), recipient survival (%), and graft neutrophil infiltration (DeltaAbs(460 nm)/min) were measured 30 minutes after transplantation of the left lung and exclusion of the right lung from the circulation. All tested conditions significantly affect post-LTX vascular homeostasis. Inflation at 10 mm Hg pressure preserved lungs significantly better than did other pressures. There was a tendency for room air to improve all measured variables compared with 100% N(2) or 100% O(2) and a significant improvement in recipient survival with room air storage. Of the 3 storage temperatures investigated, 10 degrees C storage provided the best preservation in terms of PaO(2), graft neutrophil infiltration, and survival. We conclude that storage at 10 degrees C, 10 mm Hg inflation pressure, with room air establishes optimal lung storage conditions with Euro-Collins solution in this rat LTX model. These data suggest that these conditions should be used to evaluate new and potentially improved preservation strategies.

Hypothermia and prostaglandin E(1) produce synergistic attenuation of ischemia-reperfusion lung injury.

Current methods of preserving lung tissue for transplantation are inadequate. In this study, we tested whether the combination of hypothermia plus prostaglandin E(1) (PGE(1)) treatment would have synergistic attenuation on ischemia-reperfusion (I/R) lung injury. Isolated rat lung experiments with ischemia for 1 h then reperfusion for 1 h, were conducted using six different perfusates: (1) University of Wisconsin solution (UW) at 30 degrees C (n = 5), (2) UW at 22 degrees C (n = 5), (3) UW at 10 degrees C (n = 4), (4) UW+PGE(1) at 30 degrees C (n = 4), (5) UW+PGE(1) at 22 degrees C (n = 4), and (6) UW+PGE(1) at 10 degrees C (n = 4). Hemodynamic changes, lung weight gain, capillary filtration coefficients, and lung pathology were analyzed to evaluate the I/R injury. Compared with 30 degrees C UW, animals treated with 22 degrees C UW and 10 degrees C UW had less I/R lung injury, with the groups receiving 22 degrees C UW showing superior results to group receiving 10 degrees C UW. The addition of PGE(1) to UW solution produced more attenuation of I/R injury than did UW alone. Among the six groups, 10 degrees C UW+PGE(1) produced the most reduction of I/R injury. This study has shown that hypothermia can attenuate I/R injury with the optimal flushing temperature being near 22 degrees C. PGE(1) also has a protective effect on I/R. Furthermore, hypothermia and PGE(1) have synergistic attenuation of I/R lung injury. We propose that pulmonary artery flushed with cooling UW+PGE(1) might improve lung preservation and improve results in lung transplantation.

Superior protection in orthotopic rat lung transplantation with cyclic adenosine monophosphate and nitroglycerin–containing preservation solution

Background: Primary lung graft failure is common, and current lung preservation strategies are suboptimal. Because the decline in lung levels of cyclic adenosine monophosphate and cyclic guanosine monophosphate during preservation could enhance adhesiveness of endothelial cells for leukocytes as well as increase vascular permeability and vasoconstriction, we hypothesized that buttressing these levels by means of a preservation solution would significantly improve lung preservation. Methods: An orthotopic rat left lung transplantation model was used. Lungs were harvested from male Lewis rats and preserved for 6 hours at 4°C with (1) Euro-Collins solution (n = 8); (2) University of Wisconsin solution (n = 8); (3) low-potassium dextran glucose solution (n = 8); (4) Columbia University solution (n = 8), which contains a cyclic adenosine monophosphate analog (dibutyryl cyclic adenosine monophosphate) and a nitric oxide donor (nitroglycerin) to buttress cyclic guanosine monophosphate levels; or (5) Columbia University solution without cyclic adenosine monophosphate or nitroglycerin (n = 8). Pa O2, pulmonary vascular resistance, and recipient survival were evaluated 30 minutes after left lung transplantation and removal of the nontransplanted right lung from the pulmonary circulation. Results: Among all groups studied, grafts stored with Columbia University solution demonstrated the highest Pa O2 (355 ± 25 mm Hg for Columbia University solution versus 95 ± 22 mm Hg for Euro-Collins solution, P < .01, 172 ± 55 mm Hg for University of Wisconsin solution, P < .05, 76 ± 15 mm Hg for low-potassium dextran glucose solution, P < .01, and 82 ± 25 mm Hg for Columbia University solution without cyclic adenosine monophosphate or nitroglycerin, P < .01) and the lowest pulmonary vascular resistances (1 ± 0.2 mm Hg • mL –1 • min –1 for Columbia University solution versus 12 ± 4 mm Hg • mL –1 • min –1 for Euro-Collins solution, P < .01, 9 ± 2 mm Hg • mL –1 • min –1 for University of Wisconsin solution, 14 ± 6 mm Hg • mL –1 • min –1 for low-potassium dextran glucose solution, P < .01, and 8 ± 2 mm Hg • mL –1 • min –1 for Columbia University solution without cyclic adenosine monophosphate and nitroglycerin). These functional and hemodynamic improvements provided by Columbia University solution were accompanied by decreased graft leukostasis and decreased recipient tumor necrosis factor α and interleukin 1α levels compared with the other groups. In toto, these improvements translated into superior survival among recipients of Columbia University solution–preserved grafts (100% for Columbia University solution, 37% for Euro-Collins solution, P < .01, 50% for University of Wisconsin solution, P < .05, 50% for low-potassium dextran glucose solution, P < .05, and 13% for Columbia University solution without cyclic adenosine monophosphate and nitroglycerin, P < .01). Conclusion: Nitroglycerin and cyclic adenosine monophosphate confer beneficial vascular effects that make Columbia University solution a superior lung preservation solution in a stringent rat lung transplantation model. (J Thorac Cardiovasc Surg 1999;118:135-44)

Addition of aprotinin to organ preservation solutions decreases lung reperfusion injury

Background. Organ preservation injury is associated with endothelial cell damage, destabilization of mitochondrial and cell membranes, and the release of proteolytic enzymes. In addition to its well-known clinical effect of reducing perioperative blood loss, aprotinin has antiproteolytic and membrane-stabilizing properties. We hypothesized that adding aprotinin to Euro-Collins (EC) and University of Wisconsin (UW) solutions would decrease preservation injury in cultured endothelial cells and a whole organ rat lung model. Methods. Bovine aortic endothelial cells were cultured and stored in the respective solution at 4°C for 12 or 48 hours. Endothelial cell viability after storage was assessed by dimethylthiazole tetrazolium cytotoxicity assay. In the whole organ model, rat lungs were isolated, flushed with the respective solution, and stored at 4°C for 6 or 12 hours. The lungs were ventilated with 100% O 2 and reperfused with fresh blood. Alveolar–arterial O 2 difference, O 2 tension, capillary filtration coefficient, and compliance were determined. Results. Endothelial cell viability was optimized with the addition of aprotinin to EC and UW at a dose of 150 KIU/mL (0.02 mg/mL). In the isolated perfused lung model, after 6 hours of ischemic storage, aprotinin-enhanced (100 KIU/mL [0.014 mg/mL]) EC and UW decreased alveolar–arterial O 2 difference, increased O 2 tension, and decreased capillary filtration coefficient compared with EC and UW alone. After 12 hours of ischemic storage, aprotinin-enhanced EC and UW decreased alveolar–arterial O 2 difference, increased O 2 tension, decreased capillary filtration coefficient, and increased compliance compared with EC and UW alone. Conclusions. The addition of aprotinin to EC and UW solutions increases endothelial cell viability in hypoxic cold storage conditions. In terms of whole organ function, aprotinin improves lung preservation as demonstrated by increased oxygenation and compliance, and decreased capillary permeability. This study is clinically applicable as there is already extensive experience with the use of aprotinin in heart and lung transplant recipients, in addition to its routine use in conventional cardiac operations.

A newly developed solution enhances thirty-hour preservation in a canine lung transplantation model

Ischemia and reperfusion cause the production of oxygen free radicals. These damage grafts or disrupt normal vascular homeostatic mechanisms, with a parallel reduction in endothelial nitric oxide and adenosine 3′,5′-cyclic monophosphate levels. We hypothesized that lung preservation failure may be related to these events. To improve lung preservation, we prepared a new ET-Kyoto solution, which contains N -acetylcysteine (a radical scavenger), nitroglycerin (to elevate the nitric oxide level), and dibutyryl adenosine 3′,5′-cyclic monophosphate (to elevate the adenosine 3′,5′-cyclic monophosphate level) and examined its efficacy in a canine single-lung transplantation model. Lungs were flushed with new ET-Kyoto solution (group I, n = 9), basal ET-Kyoto solution (group II, n = 6), basal ET-Kyoto solution plus ethanol and propylene glycol (solvents of nitroglycerin; group III, n = 6), or low-potassium dextran glucose solution (group IV, n = 6), and stored at 4º C for 30 hours. After left single-lung transplantation, the right main bronchus and right pulmonary artery were ligated and the functions of the transplanted lung were assessed for 6 hours. Arterial oxygen tension was significantly higher in group I than in groups II, III, and IV ( p < 0.05). Peak inspiratory pressure and wet-to-dry lung weight ratio were significantly lower in group I than in groups II and IV ( p < 0.01). Histologic and ultrastructural studies showed better preservation in group I than in groups II, III, and IV. We conclude that the new ET-Kyoto solution provides enhanced 30-hour lung preservation. (J T HORAC C ARDIOVASC S URG 1996;112:569-76)

Prostaglanding E 1 or prostacyclin in euro-collins solution fails to improve lung preservation

In search of the ideal composition of the flush solution for pulmonary preservation, we studied the effects of prostaglandin E1 (PGE1) and prostacyclin as an additive to Euro-Collins solution (ECS) on pulmonary hemodynamics and gas exchange in a porcine single lung transplantation model using extracorporeal circulation and right heart bypass. Twenty-two pigs served as donors. The animals were randomized to receive either modified ECS alone (control group, n = 8), ECS with 100 micrograms/L of PGE1 (PGE1 group, n = 6), or ECS with 200 micrograms/L of prostacyclin (prostacyclin group, n = 8). Left lung transplantation was performed in 22 recipients after approximately 4 hours of cold ischemia. Carbon dioxide elimination was significantly depressed in the two prostaglandin groups, and the use of PGE1 was associated with a significant decrease in arterial oxygen tension compared with the control group. Both drugs were inefficient in alleviating the increase in pulmonary vascular resistance after transplantation. The use of prostaglandins as constituents of the flush solution was not followed by any improvement of early graft function after cold ischemia.

Enhanced Preservation of Orthotopically Transplanted Rat Lungs by Nitroglycerin but Not Hydralazine

Nitric oxide (NO) produced within the lungs maintains pulmonary vascular homeostatic properties, modulating leukocyte traffic, platelet aggregation, and vasomotor tone. Because reactive oxygen intermediates generated during reperfusion react rapidly with available NO, we hypothesized that the NO donor nitroglycerin (NTG) would enhance lung preservation for transplantation by improving graft blood flow and reducing graft neutrophil and platelet sequestration. By use of an orthotopic rat left lung transplant model, with ligation of the native right pulmonary artery to ensure that recipient survival and physiological measurements depend entirely on the transplanted lung, transplants were performed in 70 male Lewis rats after 6-hour 4 degrees C preservation in Euro-Collins solution (EC) alone or EC with supplemental NTG. Compared with EC alone, supplemental NTG significantly increased pulmonary arterial flow (2.2 +/- 1.4 to 21.4 +/- 2.9 mL/min, P < .01), decreased pulmonary vascular resistance (7.4 +/- 2.0 to 1.4 +/- 0.1 x 10(3) Woods units, P < .05), improved arterial oxygenation (163 +/- 57 to 501 +/- 31 mm Hg, P < .01), and enhanced recipient survival (17% to 100%, P < .001). These beneficial effects of NTG were dose dependent over a range of 0.001 to 0.1 mg/mL. Although NTG caused significant pulmonary vasodilation during the harvest/flushing period, the direct-acting vasodilator hydralazine caused greater vasodilation than did NTG but was associated with poor graft function, elevated pulmonary vascular resistance, and poor recipient survival. To explore nonvasodilator protective mechanisms of NTG, graft neutrophil and platelet sequestration were studied; supplemental NTG significantly reduced both neutrophil and platelet accumulation compared with either hydralazine or EC alone.(ABSTRACT TRUNCATED AT 250 WORDS)