Journal of Applied Physiology
Vol. 83, No. 2, pp. 583-590, August 1997
PULMONARY CIRCULATION AND LUNG FLUID BALANCE

PGE₁, dexamethasone, U-74389G, or Bt₂-cAMP as an additive to promote protection by UW solution in I/R injury

Chi-Huei Chiang¹, Kang Hsu¹, Horng-Chin Yan¹, Horng-Jyh Harn³, and Deh-Ming Chang²

¹ Pulmonary and ² Rheumatology/Immunology Divisions, ³ Department of Pathology, Tri-Service General Hospital, National Defense Medical Center, Taipei 100, Taiwan, Republic of China

ABSTRACT

INTRODUCTION

METHODS

RESULTS

DISCUSSION

ACKNOWLEDGEMENTS

FOOTNOTES

REFERENCES

ABSTRACT

Chiang, Chi-Huei, Kang Hsu, Horng-Chin Yan, Horng-Jyh Harn, and Deh-Ming Chang. PGE₁, dexamethasone, U-74389G, or Bt₂-cAMP as an additive to promote protection by UW solution in I/R injury. J. Appl. Physiol. 83(2): 583-590, 1997.A method to reduce ischemia-reperfusion (I/R) injury can be an important criterion to improve the preservation solution. Although University of Wisconsin solution (UW) works as a lung preservation solution, its attenuation effect on I/R injury has not been investigated. We attempted to determine whether, by adding various protective agents, modified UW solutions will enhance the I/R attenuation by UW. We examined the I/R injury in an isolated rat lung model. Various solutions, e.g., physiological salt solution (PSS), UW, and modified UW solutions containing various protective agents such as prostaglandin E₁, dexamethasone, U-74389G, or dibutyryl adenosine 3,5-cyclic monophosphate were perfused individually to evaluate the I/R injury. Isolated rat lung experiments, with ischemia for 45 min, then reperfusion for 60 min, were conducted in a closed circulating system. Hemodynamic changes, lung weight gain (LWG), capillary filtration coefficient (K_fc), protein content of lavage fluid, concentration of cytokines, and lung histopathology were analyzed. Results showed that the acute I/R lung injury with immediate permeability pulmonary edema was associated with an increase in tumor necrosis factor- (TNF-) production. A significant correlation existed between TNF- and K_fc (r = 0.8, P < 0.0001) and TNF- and LWG (r = 0.9, P < 0.0001), indicating that TNF- is an important cytokine modulating early I/R injury. Significantly lower levels of K_fc, LWG, TNF-, and protein concentration of lung lavage (P < 0.05) were found in the UW-perfused group than in the control group perfused with PSS. Modified UW promoted the protective effect of UW to further decrease K_fc, LWG, and TNF- (P < 0.05). Histopathological observations also substantiated this evidence. In the UW+U-74389G group, bronchial alveolar lavage fluid contained lowest protein concentration. We conclude that the UW solution attenuates I/R injury of rat lung and that the modified UW solutions further enhance the effect of UW in reducing I/R injury. Among modified solutions, UW+U-74389G is the best. Further investigation of the improved effects of the modified UW solutions would be beneficial in lung transplantation.

ischemia-reperfusion; prostaglandin E₁; dibutyryl adenosine 3,5-cyclic monophosphate; U-74389G; University of Wisconsin solution; lung injury

INTRODUCTION

DESPITE INTENSIVE STUDIES, none of the clinically applied lung preservation solutions permits reliable preservation of human lung allografts for longer than 6 h (6, 21). The susceptibility of lung tissue to ischemia-reperfusion (I/R) injury has made preservation of lungs more difficult than of other organs (15, 22). Theoretically, a reduction in I/R injury will increase preservation time and improve the early lung function. Therefore, we used a reduction of the I/R injury in lung as a criterion to evaluate the preservation solutions.

The University of Wisconsin solution (UW) was developed by Wahlberg and colleagues in 1986 and has made a major impact on the preservation of solid organs for transplantation (45). Experimental and clinical applications of UW expanded to pancreas, kidney, liver, and even the heart. Considering the experience of the Pittsburgh lung transplant group, UW is at least equivalent to the modified Euro-Collins solution used in lung transplantation (14). However, the optimal solution for the preservation of lung is still undefined. Although UW works as a preservation solution for lung, its attenuation effect on I/R injury has not been explored. To improve UW as a lung preservation solution, we attempted to enhance its attenuation effects by adding some protective agents. A modified UW solution containing various protective agents was tested for lung injury, and we found that certain modifications better protected the rat lung from I/R injury.

Substantial literature shows that some of the commonly used protective agents such as prostaglandin E₁ (PGE₁), dexamethasone (Dex), dibutyryl-adenosine 3,5-cyclic monophosphate (Bt₂-cAMP), and U-74389G (an experimental drug of the lazaroid class) have been postulated to exert a positive effect on the reduction of acute lung injury (5, 13, 18, 27, 28, 36). In this study, we hypothesized that modifications of UW solution by adding protective agents will enhance its protective effects from the acute I/R lung injury. A well-established I/R rat model (39, 46) was adapted to investigate the protective effect of UW and of the modified solutions of UW on I/R injury. From the results obtained, we demonstrate that UW can attenuate I/R injury and that the modified UW solutions can further enhance the protective effect of UW against I/R lung injury.

METHODS

Preparation of isolated and perfused rat lungs. The procedures to prepare isolated-perfused lung in situ in the chest were previously described (39, 46). Male Sprague-Dawley rats (250-350 g body wt) were anesthetized with pentobarbital sodium (20-25 mg ip). A tracheotomy was performed and permitted ventilation with a Harvard rodent ventilator (model 683) at 55 breaths/min, a tidal volume of 2.5 ml, and positive end-expiratory pressure of 2 cmH₂O. The inspired gas mixture was 5% CO₂-95% air. After median sternotomy was performed, heparin (1 unit/g body wt) was injected into the right ventricle. Blood was drawn from the right ventricle and discarded. A cannula was placed in the pulmonary artery through a puncture into the right ventricle, and tight ligature was placed around the main trunk of the pulmonary artery. A large catheter was inserted into the left atrium through the left ventricle and mitral valve, fixed by ligature at the apex of the heart, and was used to divert pulmonary venous outflow into a reservoir. A third ligature was placed above the atrioventricular junction to prevent perfusate flow into the ventricles. The lungs were perfused by using a peristaltic pump (Minipuls 2; Gilson Medical Electronic, Middleton, WI) with various perfusates at a constant flow of 0.03 ml · g body wt¹ · min¹. The initial 75 ml of lactate Ringer solution perfusate, which contained residual blood cells and plasma, were discarded and not recirculated. An additional 25 ml of various perfusates were used for recirculation. Perfusion fluid was maintained at 25°C. Pulmonary arterial (Ppa) and pulmonary venous (Ppv) pressures were continuously monitored with pressure transducers (Statham P23 ID) from a sidearm of the inflow and outflow cannulas and recorded on a polygraph recorder (Gould Instruments, Cleveland, OH). The Ppv was set at 2.5 mmHg by adjusting the height of the venous reservoir. Zone 3 condition (arterial > venous > alveolar pressures) was maintained throughout all experiments.

The isolated perfused lung remained in situ, and the weight of the rat was monitored on an electrical balance and recorded on an oscillograph after digital-to-analog conversion. The changes in body weight were measured as a result of changes in lung weight, according to the method of Wang et al. (46). In this study, the isolated lung preparation was selected based on the following three criteria: 1) no leakage observed at the sites of cannula insertion, 2) no evidence of edema in lung examined by observation, and 3) an isogravimetric state.

Perfusates. Several perfusates were used. 1) Physiological salt solution (PSS) contained 4% bovine serum albumin (Sigma Chemical, St. Louis, MO) and (in mM) 119 NaCl, 4.7 KCl, 1.17 MgSO₄, 22.6 NaHCO₃, 1.18 KH₂PO₄, 3.2 CaCl₂, and 5.5 glucose. 2) UW (DuPont-Merck Pharmaceuticals, Wilmington, DE) was composed of (in g/l) 50 pentastarch, 35.83 lactobionic acid, 3.4 potassium phosphate monobasic, 1.23 magnesium sulfate heptahydrate, 17.83 raffinose pentahydrate, 1.34 adenosine, 0.136 allopurinol, and 0.922 glutathione. Osmolarity was at 320 mosmol, including sodium concentration of 29 meq/l and that of potassium of 125 meq/l; pH was 7.4 (Table 1). 3) Four kinds of modified UW solutions were prepared as follows: UW+U-74389G (0.04 g/ml, a potent inhibitor of lipid peroxidation, kindly provided by Upjohn); UW+Dex (Sigma Chemical; 0.04 mg/ml); UW+Bt₂-cAMP (Sigma Chemical; 1 mg/l); and UW+PGE₁ (Sigma Chemical; 20 µg/l).

Table  1.   Composition of University of Wisconsin solution Additive Amount Added, mmol/l Impermeant   Lactobionic acid 100   Raffinose pentahydrate 30 Oncotic agents   Pentastarch 5 g/dl Antioxidants   Allopurinol 1   Glutathione 3 Metabolic substrates   Adenosine 5 Buffers   KH2PO4 25 Electrolytes   Potassium 125   Sodium 29   Magnesium 5   Sulfate 5 pH 7.4 Osmolarity, mosmol/l 320

Determination of pulmonary capillary pressure (Ppc). The Ppc was estimated by using the double-occlusion method (16). Arterial inflow and venous outflow lines were occluded simultaneously, and the equilibrium Ppa and Ppv were measured. This equilibration pressure is well correlated with isogravimetric measurements of Ppc and also reflects the prevailing capillary pressure when the lung is not isogravimetric.

Calculation of pulmonary vascular resistance. The pulmonary arterial (Ra) and venous resistances (Rv) were calculated from the following equations: Ra = (Ppa  Ppc)/; and Rv = (Ppc  Ppv)/, respectively, where is flow.

Measurement of microvascular permeability. Pulmonary capillary filtration coefficient (K_fc) was used as an index of microvascular permeability to water. The K_fc was measured by using the method described previously (9). Briefly, after an isogravimetric period, Ppv was rapidly elevated to 6-8 cmH₂O for 15 min. The increase in lung weight was recorded, and a characteristic rapid weight gain (vascular filling) was followed by a slower rate of weight gain. The rate of weight change (Wt/t) during the 6- to 14-min interval was analyzed by using linear regression of the log₁₀-transformed rates of weight changes per minute. The initial rate of weight gain was calculated by using extrapolation of Wt/t to time 0. K_fc was calculated by dividing Wt/t at time 0 by the changes in Ppc that occurred after venous outflow pressure was increased, normalized using the baseline wet lung weight, and expressed as milliliters per minute per centimeter H₂O per 100 g of lung tissue.

Measurement of protein concentration in lung lavage fluid. All experiments were terminated after 60 min of closed extracorporeal perfusion, and the lungs were removed and wet weights were measured. The lungs were lavaged twice with saline (2.5 ml/lavage). Lavage samples were centrifuged at 1,500 g in at room temperature for 10 min. The concentration of protein was determined as previously described (8).

Tumor necrosis factor- (TNF-) and interleukin-1 (IL-1) assay. After experimentation, 2 ml of perfusate in the reservoir pool were drawn into sterile tubes and stored at 70°C until the assay was performed. Based on the enzyme-linked immunosorbent assay (ELISA), these collected perfusate samples and standards were determined by mouse TNF- or IL-1 kit (Genzyme, Cambridge, MA), respectively. All samples were tested in duplicate. The assay was done as follows. First, a 96-well microtiter plate (precoated with monoclonal anti-TNF- or IL-1) was used to capture TNF- or IL-1 in standards and test samples. After the plate was washed to remove unbound material, a peroxidase-conjugated polyclonal anti-TNF- or IL-1 (horseradish peroxidase conjugate), which binds to captured TNF- or IL-1, was added. The plate was washed again. Then a substrate solution was added, which initiated a peroxidase-catalyzed color change that was subsequently stopped by acidification. The absorbance measured on an ELISA reader (Microplate Reader 450; Bio-Rad, CA) at 450 nm was proportional to the concentration of TNF- or IL-1 present in the standards or samples. A standard curve was obtained by plotting the concentrations of TNF- or IL-1 standards vs. their resulting absorbance. The TNF- or IL-1 concentrations in experimental samples were then determined using the standard curve.

Experimental protocols. The studies were divided into seven groups. 1) PSS (no I/R injury) as negative control that showed no I/R injury (n = 6); 2) PSS as positive control displaying I/R injury (n = 5); 3) UW (n = 7); 4) UW+U-74389G (n = 5); 5) UW+Dex (n = 5); 6) UW+Bt₂-cAMP (n = 5); and 7) UW+PGE₁ (n = 5). The isolated lungs were perfused with one of above-designated perfusates. The closed system of circulation was maintained at constant flow, volume, pressure, and temperature. The experiment was initiated after hemodynamic stability for 15 min in the extracorporeal isolated lung circulation. In group 1, the isolated lung was perfused with PSS for 105 min but without I/R challenge. Groups 2, 3, 4, 5, 6, and 7 were perfused with a designated solution and received I/R challenge. The protocol of I/R injury challenge was as follows: the isolated lung was not ventilated and perfused for 45 min (ischemia), followed by reinstitution of ventilation and perfusion (reperfusion) for 60 min.

Lung histopathology. After termination of the experiment, the whole lungs were dissected and immediately fixed in 10% neutral buffered Formalin. After fixation, the right middle lobes were dehydrated through a grade series of alcohol, cleared in xylene, and embedded in paraffin. All sections were cut at 5 µm and stained with hematoxyline and eosin.

Statistical analysis. Values are expressed as means ± SD. Comparison among all groups for a given variable were done by using one-way analysis of variance and Dunnett's method. Comparisons between baseline and postreperfusion, within each group for a given variable, were made by using paired Student's t-test. P < 0.05 was considered statistically significant.

RESULTS

Table  2.   Kfc values and protein concentrations of lavage fluid Group n Kfc Protein in Lavage Fluid Baseline After I/R After I/R 1: PSS (no I/R) 6 0.35 ± 0.05  0.37 ± 0.04 Not detected 2: PSS 5 0.42 ± 0.03  0.84 ± 0.19 428.0 ± 222.7  3: UW 7 0.41 ± 0.06  0.52 ± 0.12 50.5 ± 14.9 4: UW + U-74389G 5 0.27 ± 0.05* 0.32 ± 0.05, § 30.4 ± 13.4, § 5: UW + Dex 5 0.29 ± 0.05* 0.32 ± 0.05, § 37.4 ± 12.6 6: UW + Bt2-cAMP 5 0.29 ± 0.05* 0.35 ± 0.09, § 32.5 ± 7.14 7: UW + PGE1 5 0.27 ± 0.05* 0.34 ± 0.05, § 42.3 ± 20.6 Values are means ± SD; n, no. of rats. Capillary filtration coefficient (Kfc) is in ml · min1 · cmH2O 1 · 100 g lung wt1; unit of protein concentration is mg/100 ml. PSS, physiological salt solution; I/R, ischemia-reperfusion; UW, University of Wisconsin solution; Dex, dexamethasone; Bt2-cAMP, dibutyryl adenosine 3,5-cyclic monophosphate; PGE1, prostaglandin E1. * P < 0.05 compared with PSS; P < 0.05 compared with baseline; P < 0.05 compared with group 2; § P < 0.05 compared with UW group.

Table  3.   Hemodynamics Group Ppa Ppv Ppci Ra Rv Before ischemia (baseline) 1: PSS (no I/R) 17.70 ± 0.97  2.80 ± 0.27  9.43 ± 0.24  0.98 ± 0.08  0.77 ± 0.06  2: PSS 18.70 ± 4.10  4.40 ± 1.78  10.69 ± 2.69  0.94 ± 0.18  0.74 ± 0.14  3: UW 28.30 ± 3.01* 2.10 ± 0.55  13.63 ± 1.38* 1.72 ± 0.20* 1.36 ± 0.16* 4: UW + U-74389G 27.50 ± 3.20* 1.40 ± 0.65  12.88 ± 1.49* 2.32 ± 1.35* 1.35 ± 0.17* 5: UW + Dex 27.30 ± 2.66* 2.30 ± 0.57  12.79 ± 0.48* 1.65 ± 0.20* 1.30 ± 0.16* 6: UW + Bt2-cAMP 28.50 ± 0.50* 2.30 ± 0.45  13.83 ± 0.42* 1.72 ± 0.03* 1.36 ± 0.02* 7: UW + PGE1 29.80 ± 2.25* 2.40 ± 0.42  14.46 ± 0.81* 1.80 ± 0.17* 1.42 ± 0.13* After I/R 1: PSS (no I/R) 18.60 ± 1.64  1.80 ± 0.57  10.22 ± 0.81  1.04 ± 0.09  0.82 ± 0.07  2: PSS 27.00 ± 6.47 4.30 ± 1.79  14.29 ± 3.25 1.50 ± 0.41 1.13 ± 0.38 3: UW 26.10 ± 2.90 2.20 ± 0.57  12.72 ± 1.45  1.62 ± 0.26  1.20 ± 0.12  4: UW + U-74389G 24.00 ± 1.70 1.50 ± 0.87  11.04 ± 0.82 1.49 ± 0.09  1.16 ± 0.07 5: UW + Dex 23.80 ± 2.41 2.10 ± 0.74  11.47 ± 0.39 1.43 ± 0.21 1.12 ± 0.16 6: UW + Bt2-cAMP 24.50 ± 1.00 2.20 ± 1.10  12.01 ± 1.10 1.54 ± 0.08  1.15 ± 0.04 7: UW + PGE1 25.90 ± 2.46 2.40 ± 1.19  12.74 ± 1.34 1.55 ± 0.17 1.21 ± 0.14 Values are means ± SD; Ppa and Ppv (mmHg), pulmonary arterial and venous pressure, respectively; Ppci (mmHg), isogravimetric capillary pressure; Ra and Rv (cmHg · min · ml1), arterial and venous resistance, respectively. * P < 0.05 compared with PSS (no I/R); P < 0.05; P < 0.001 compared with baseline.

Changes in TNF- and IL-1.

Table  4.   Concentration of IL-1 after I/R challenge Group n Value ± SD, pg/ml 1: PSS (no I/R) 4 10.4 ± 1.8  2: PSS 4 11.8 ± 2.9  3: UW 4 10.6 ± 2.2  4: UW + U-7389G 5 10.1 ± 1.2  5: UW + Dex 5 10.6 ± 1.9  6: UW + Bt2-cAMP 5 10.1 ± 1.5  7: UW + PGE1 5 10.1 ± 0.7 Values are means ± SD; n, no. of rats. IL-1, interleukin-1.

DISCUSSION

In this study, the UW perfusate showed a significant decrease in Ppa, K_fc, LWG, TNF-, and protein content in the lavage fluid. Inflammatory cell infiltration in alveoli was decreased. Therefore, the UW perfusate solution has a protective effect on I/R injury. In addition, a further decrease of LWG, K_fc, and inflammatory cell infiltration was observed in all groups of modified UW. We conclude that PGE₁, Dex, U-74389G, or Bt₂-cAMP added to UW solution gave better protection from I/R injury than did UW alone. In the UW+U-74389G group, BAL contained lowest protein concentration. Using the reduction in I/R injury as an important criterion of lung preservation, we found that U-74389+UW is the best solution.

At initial experimentation, the rat lungs were flushed with 75 ml of lactate Ringer solution under zone 3 conditions and 1 × 10⁵ leukocytes/ml found in perfusate. Hence, the initial concentrations of leukocytes in all closed-perfusion circuits were the same; therefore, the variations in levels of I/R injury present in different groups of perfusate were not due to initial concentrations of cells. A marked leukocyte infiltration into the interstitial and perivascular regions in the PSS group was indicating that isolated lungs contained leukocytes and that these leukocytes played a role in I/R lung injury. Compared with changes observed in leukocyte infiltration in various groups of perfusates, we found that in the UW and modified UW groups many fewer circulating leukocytes were recruited into the lung. This was due to reduction in leukocyte adherence to the capillary and migration to interstitial tissues and alveoli; therefore, less microvascular injury was seen (35).

Higher baseline values of Ppa were found in both the standard and modified UW solutions than in the PSS group. A high potassium concentration (125 meq/l in UW vs. 4.7 meq/l in PSS groups) in the UW may be responsible for the increased peripheral vascular resistance and Ppa during pulmonary arterial flush. It is well known that a high extracellular potassium concentration depolarizes smooth muscle cell membranes and causes smooth muscle contraction (32). After I/R, a significant increase in pulmonary vascular pressure and resistance was found, but not in Ppv, in the PSS. This was reportedly due to leukocyte aggregation and adherence to the capillary (35) and to released vasoactive substance. We suggest in this report that a significant decrease of pulmonary pressure and resistance observed in UW and modified UW groups resulted from a reduction of adherence and recruiting leukocytes to lung tissue. The pathological findings were also indicating less leukocyte migration.

The baseline values of K_fc in modified UW groups were lower than those in UW, but no significant difference of baseline Ppa existed in UW and modified UW. It suggests that protective agents added to UW decreased K_fc by altering permeability, not by changing surface area of pulmonary capillary, which resulted from vasoactive effects.

The exact mechanism of UW attenuation of I/R injury to the lung remains unclear. Definitely, the UW solution contains protective substances that prevent I/R injury. Other investigators (3, 40) have suggested that lactobionate and raffinose in UW are osmotically active nonmetabolic impermeants and that they suppress cellular swelling. Glutathione and allopurinol prevent and reduce cytotoxic injury from oxygen free radicals (3). In addition, adenosine provides the substrate for cell to regenerate ATP during reperfusion after cold storage (40). Previous studies have shown that the increased microvascular permeability associated with I/R can be reversed by cAMP (36). The mechanism by which Bt₂-cAMP exerts beneficial effects in animal models of I/R lung injury and decreases microvascular permeability is not clearly known. A possible explanation is that the cytoskeleton altered the endothelial cells in vessels that produced tighter intercellular junctions (23, 38). Goodman et al. (12) have suggested an activated ionic transport from air space to interstitium, which contributes to the beneficial effect of Bt₂-cAMP by removing edema fluid from the air space. In this study, we demonstrated that Bt₂-cAMP modified the TNF- release in UW perfusate and suggested that the mechanism of I/R attenuation is due to a multiple actions of Bt₂-cAMP, including the inhibition of TNF- production.

With the exception of the vasodilating effect (26, 30), PGE₁ has a bronchodilating effect (29), inhibits aggregation of platelets and leukocytes (30, 46), suppresses TNF- production (23), has immunosuppressive effects (20, 23, 42), and has a variety of "cytoprotective" effects (10, 11, 34). However, the exact action that is responsible for amelioration of I/R injury is not clearly known.

Recently, a novel series of 21-aminosteroids (lazaroids), which are potent inhibitors of iron-dependent lipid peroxidation, has been developed (4). These agents have proven very effective in protecting tissues from ischemic damage. Our results, similar to others (2, 5, 16), showed that U-74389G enhanced UW preservation solution to protect against I/R injury. In this study, we demonstrated that U-74389G enhanced the UW by inhibiting TNF- production and suggest that U-74389G in preservation solution was not only preventing lipid peroxidation but also suppressing TNF--mediated inflammation. TNF- has been expressed in acute lung injury, reminiscent of acute respiratory distress syndrome in many animal models (41, 43). TNF- was shown to induce the expression of both intercellular cell adhesion molecule-1 and endothelial leukocyte adhesion molecule-1 (26, 49) and to mediate polymorphonuclear neutrophil attachment to endothelial cells. Adherence of polymorphonuclear neutrophil to endothelial cells results in release of neutrophil-derived oxygen metabolites, which leads to vascular and tissue injury (1, 17, 19). The elevation of TNF- during reperfusion after ischemia was accompanied by severe lung I/R injury in the PSS group. Similar results were also demonstrated by others in I/R injury of liver (7) and lung (33). Palace et al. (33) have suggested that neutrophil sequestration resulting in lung injury after reperfusion is dependent on generation of TNF-. In contrast, studies of Serrick et al. (37) showed no elevation of TNF- in a lung autograft animal model. The role of TNF- in I/R injury is clear. This study demonstrated that the UW solution produced less TNF- than the control group; the TNF- levels revealed a significant correlation to the changes of LWG and K_fc, suggesting that TNF- production was associated with the severity of lung injury.

In conclusion, the animal model used to measure I/R lung injury in our studies is simple, reliable, and inexpensive (39, 46). This method provides an effective way to screen solutions that would be best to use in lung transplantation.

ACKNOWLEDGEMENTS

The authors thank professor Emil Chi, University of Washington, and Dr. Bi-Lian Li for reading this manuscript and Upjohn Company for a generous supply of U-74389G.

FOOTNOTES

Address for reprint requests: C.-H. Chiang, Pulmonary Division, Tri-Service General Hospital No. 8, Section 3, Ting-Chow Rd., Taipei, Taiwan, Republic of China (E-mail: c38621{at}ms10.hinet.net).

Received 23 May 1996; accepted in final form 13 March 1997.

REFERENCES

1.	Adkins, W. K., and A. E. Taylor. Role of xanthine oxidase and neutrophils in ischemia-reperfusion injury in rabbit lung. J. Appl. Physiol. 69: 2012-2018, 1990[Abstract/Free Full Text].
2.	Aeba, R., W. A. Killinger, R. J. Keenan, S. A. Yousem, I. Hamamoto, R. L. Hardesty, and B. P. Griffith. Lazaroid U74500A as an additive to University of Wisconsin solution for pulmonary grafts in the rat transplant model. J. Thorac. Cardiovasc. Surg. 104: 1333-1339, 1992[Abstract].
3.	Belzer, F. O., and J. H. Southard. Principles of solid-organ preservation cold storage. Transplantation 45: 673-679, 1988[Medline].
4.	Braughler, J. M., J. F. Pregenzer, R. L. Chase, L. A. Duncan, E. J. Jacobson, and J. M. McCall. Novel 21-aminosteroids as potent inhibitors of iron-dependent lipid peroxidation. J. Biol. Chem. 262: 10438-10440, 1987[Abstract/Free Full Text].
5.	Chen, H., D. Xu, S. Qi, M. Aboujaoude, J. Senechal, and P. Daloze. 21-Aminosteroid lipid peroxidation inhibitor U-74389G protects the small bowel in the rat against warm and cold damage. Transplant. Proc. 26: 1483-1484, 1994[Medline].
6.	Cooper, J. D., and C. E. Vreim. NHLBI workshop summarybiology of lung preservation for lung transplantation. Am. Rev. Respir. Dis. 146: 803-807, 1992[Medline].
7.	Colletti, L., D. Remick, G. Burtch, S. Kunkel, R. Strieter, and D. Campbell. Role of tumor necrosis factor-alpha in the pathophysiologic alterations after hepatic ischemia/reperfusion injury in rat. J. Clin. Invest. 85: 1936-1934, 1990.
8.	Doumas, B. T. Determination of serum albumin. Standard Methods Clin. Chem. 7: 175-177, 1972.
9.	Drake, R., K., A. Gaar, and A. E. Taylor. Estimation of the filtration coefficient of pulmonary exchange vessels. Am. J. Physiol. 234 (Heart Circ. Physiol. 3): H266-H274, 1978[Abstract/Free Full Text].
10.	Fantone, J. C., S. L. Kunklel, P. A. Ward, and R. B. Zurier. Suppression by prostaglandin E1 of vascular permeability induced vasoactive inflammatory mediators. J. Immunol. 125: 2591-2596, 1980[Abstract].
11.	Fantone, J. C., W. A. Marasco, L. T. Elgas, and P. A. Ward. Stimulus specificity of prostaglandin inhibition of rabbit polymorphonuclear leukocyte lysosomal enzyme release and superoxide anion production. Am. J. Pathol. 115: 9-16, 1984[Abstract].
12.	Goodman, B. E., K. J. Kim, and E. D. Crandall. Evidence for active sodium transport across alveolar epithelium of isolated rat lung. J. Appl. Physiol. 62: 2460-2466, 1987[Abstract/Free Full Text].
13.	Hall, T. S., A. M. Borkon, and G. C. Gurtner. Improved static lung preservation with corticosteroid and hypothermia. J. Heart Transplant. 7: 348-352, 1988[Medline].
14.	Hardesty, R. L., R. Aeba, J. M. Armitage, R. L. Kormos, and B. P. Griffith. A clinical trial of University of Wisconsin solution for pulmonary preservation. J. Thorac. Cardiovasc. Surg. 105: 660-666, 1993[Abstract].
15.	Haverich, A., W. C. Scott, and S. W. Jamieson. Twenty years of lung preservationa review. Heart Transplant. 4: 234-240, 1985.
16.	Haynes, J., A. Seibert, J. B. Bass, and A. E. Taylor. U-74500A inhibition of oxidant-mediated lung injury. Am. J. Physiol. 259: 144-148, 1990.
17.	Hogg, J. L. Neutrophil kinetics and lung injury. Physiol. Rev. 67: 1249-1287, 1987[Abstract/Free Full Text].
18.	Hooper, T. L., M. T. Jones, D. S. Thomson, L. Cook, S. Owen, S. Wilkes, A. Woodcock, and C. G. A. McGregor. Modulation of ischemic lung injury by corticosteroid. Transplantation 50: 530-532, 1990[Medline].
19.	Horgan, M. J., S. D. Wright, and A. B. Malik. Antibody against leukocyte integrin (CD18) prevents reperfusion-induced lung vascular injury. Am. J. Physiol. 259 (Lung Cell. Mol. Physiol. 3): L315- L319, 1990[Abstract/Free Full Text].
20.	Imura, M., K. Higashi, I. Yada, S. Namikawa, H. Yuasa, and M. Kusagawa. Effect of prostaglandin E1 on the prolongation of rat cardiac allograft survival. Transplant. Proc. 19: 1312-1315, 1987[Medline].
21.	Keenan, R. J., B. P. Griffith, M. Zeanti, R. L. Kormos, J. M. Armitage, and R. L. Dardesty. Increased peri-operative pulmonary preservation injury with lung procurement by Euro-Collins flush. J. Heart Lung Transplant. 10: 560-565, 1991.
22.	Kirk, A. J. B., I. W. Colquhoun, and J. H. Dark. Lung preservation: a review of current practice and future directions. Ann. Thorac. Surg. 56: 990-1000, 1993[Abstract].
23.	Kunkel, S. L., D. G. Remick, M. Spengler, and S. W. Chensue. Modulation of macrophage-derived interleukin-1 and tumor necrosis factor by prostaglandin E2. Adv. Prostaglandin Thromboxane Leukotriene Res. 17: 155-158, 1987.
24.	Langeler, E. G., and V. W. M. Van Hinsberch. Norepinephrine and iloprest improve barrier function of human endothelial cell monolayers: role of cAMP. Am. J. Physiol. 260 (Cell Physiol. 29): C1052-C1059, 1991[Abstract/Free Full Text].
25.	Leung, D. Y. M., R. S. Pober, and R. S. Cotran. Expression of endothelial-leukocyte adhesion molecule-1 in elicited late-phase allergic reaction. J. Clin. Invest. 87: 1805-1809, 1991.
26.	Long, W. A., and L. J. Rubin. Prostacyclin and PGE1 treatment of pulmonary hypertension. Am. Rev. Respir. Dis. 136: 773-776, 1987[Medline].
27.	Matsuzaki, Y., T. K. Waddell, J. D. Puskas, T. Hirai, S. Nakajima, A. S. Slutsky, and G. A. Patterson. Amelioration of post-ischemic lung reperfusion injury by prostaglandin E1. Am. Rev. Respir. Dis. 148: 882-889, 1993[Medline].
28.	Matsumura, A., K. Nakahara, S. Miyoshi, T. Mizuta, A. Akashi, and Y. Kawashima. Filtration coefficient in isolated preserved and reperfused canine lung. J. Surg. Res. 50: 250-261, 1991.
29.	Moncada, S., R. J. Flower, and J. R. Vane. Prostaglandins, prostacyclin, thromboxane A2, and leukotrienes. In: The Pharmacological Basis of Therapeutics (7th ed.)., edited by A. G. Gilman, L. S. Goodman, T. W. Rall, and F. Murad. New York: Macmillan, 1985, p. 660-673.
30.	Mulvin, D., K. Jones, R. Howard, M. Grosso, J. Repine, and M. Johnston. The effect of prostacyclin as a constituent of a preservation solution in protecting lungs from ischemic injury because of its vasodilatory properties. Transplantation 49: 828-830, 1990[Medline].
31.	Novick, R. J., A. H. Menkis, and F. N. Mckenzie. New trends in lung preservation: a collective review. J. Heart Lung Transplant. 11: 377-392, 1992[Medline].
32.	Oka, T., J. D. Puskas, E. Mayer, P. F. G. Cardoso, S. Shi, W. Wisser, A. S. Slutsky, and G. A. Patterson. Low-potassium UW solution for lung preservation: comparison with regular UW LPD and Euro-Collins Solution. Transplantation 52: 984-988, 1991[Medline].
33.	Palace, C. P., P. J. Del Vecchio, M. J. Horgan, and A. B. Malik. Release of tumor necrosis factor after pulmonary artery occlusion and reperfusion. Am. Rev. Respir. Dis. 147: 143-147, 1993[Medline].
34.	Rovert, A. Cytoprotection by prostaglandins. Gastroenterology 77: 761-767, 1979[Medline].
35.	Seibert, A. F., J. Haynes, and A. Taylor. Ischemia-reperfusion injury in the isolated rat lung: role of flow and endogenous leukocytes. Am. Rev. Respir. Dis. 147: 270-275, 1993[Medline].
36.	Seibert, A. F., W. J. Thompson, A. Taylor, W. H. Wilborn, J. Barnard, and J. Haynes. Reversal of increased microvascular permeability associated with ischemia-reperfusion: role of cAMP. J. Appl. Physiol. 72: 369-395, 1992.
37.	Serrick, C., S. L. Franchesca, A. Giaid, and H. Shennib. Cytokine interleukin-2, tumor necrosis factor-alpha, and interferon- release after ischemia/reperfusion injury in a novel lung autograft animal model. Am. J. Respir. Crit. Care Med. 152: 277- 282, 1995[Abstract].
38.	Shasby, D. M., S. S. Shasby, J. M. Sullivan, and M. J. Peach. Role of endothelial cell cytoskeleton in control of endothelial permeability. Circ. Res. 51: 657-661, 1982[Abstract/Free Full Text].
39.	Shen, C. Y., D. Wang, M. L. Chang, and K. Hsu. Protective effect of mepacrine on hypoxia-reoxygenation-induced acute lung injury in rats. J. Appl. Physiol. 78: 225-231, 1995[Abstract/Free Full Text].
40.	Southard, J. H., T. M. Van Gulik, and M. S. Ametani. Important component of the UW solution. Transplantation 49: 251, 1990[Medline].
41.	Stephens, K. E., A. Ishizaka, J. W. Larrick, and T. A. Raffin. Tumor necrosis factor causes increased pulmonary permeability and edema. Am. Rev. Respir. Dis. 137: 1364-1370, 1988[Medline].
42.	Strom, T. B., and C. B. Carpenter. Prostaglandin as an effective anti-rejection therapy in rat renal allograft recipients. Transplantation 35: 279-291, 1983[Medline].
43.	Tracey, K. J., S. F. Lowry, and A. Cerami. Cachectin/TNF- in septic shock and septic adult respiratory distress syndrome. Am. Rev. Respir. Dis. 138: 1377-1379, 1988[Medline].
44.	Vane, J. R. Adventures and excursions in bioassaythe stepping stones to prostacyclin. Postgrad. Med. 59: 743-758, 1983[Free Full Text].
45.	Wahlberg, J. A., R. Love, L. Landegaard, J. H. Southard, and F. O. Belzer. 72-Hour preservation of the canine pancreas. Transplantation 43: 5-8, 1987[Medline].
46.	Wang, D., M. U. Lin, K. Hsu, C. Y. Shen, H. I. Chen, and Y. C. Lin. Air embolism-induced lung injury in isolated rat lungs. J. Appl. Physiol. 72: 1235-1242, 1992[Abstract/Free Full Text].
47.	Wegner, C. D., R. H. Gundel, P. Reilly, N. Haynes, L. Gordon Letts, and R. Rothlain. Intercellular adhesion molecule-1 (ICAM-1) in the pathogenesis of asthma. Science 247: 456-459, 1990[Abstract/Free Full Text].