ATS
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
 QUICK SEARCH:   [advanced]


     


This Article
Right arrow Abstract Freely available
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Add to Personal Folders
Right arrow Download to citation manager
Right arrow Author home page(s):
Dirk E. M. Van Raemdonck
Filip R. L. Rega
Paul R. J. De Leyn
Willem J. Flameng
Right arrow Permission Requests
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Van Raemdonck, D. E. M.
Right arrow Articles by Lerut, T. E.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Van Raemdonck, D. E. M.
Right arrow Articles by Lerut, T. E.
Related Collections
Right arrowRelated Article

Ann Thorac Surg 1996;62:233-240
© 1996 The Society of Thoracic Surgeons


Original Articles: General Thoracic

Delay of Adenosine Triphosphate Depletion and Hypoxanthine Formation in Rabbit Lung After Death

Dirk E. M. Van Raemdonck, MD, Nicole C. P. Jannis, Filip R. L. Rega, Paul R. J. De Leyn, MD, PhD, Willem J. Flameng, MD, PhD, Toni E. Lerut, MD, PhD

Center for Experimental Surgery and Anesthesiology, Katholieke Universiteit Leuven, Leuven, Belgium


    Abstract
 Top
 Footnotes
 Abstract
 Introduction
 Material and Methods
 Results
 Comment
 Acknowledgments
 References
 
Background. If lungs could be retrieved for transplantation from non-heart-beating cadavers, the shortage of donors might be significantly alleviated.

Methods. Adenosine triphosphate (ATP) and hypoxanthine levels were measured postmortem in rabbit lungs comparing deflation (group 1), ventilation with room air (group 2), inflation with room air (group 3), ventilation with oxygen (group 4), ventilation with cooled air (group 5), deflation plus cadaver cooling (group 6), and cooling by pulmonary arterial flush (group 7).

Results. The level of ATP dropped to 25.9% and HYP increased elevenfold at 30 minutes in group 1 but remained constant during 24 hours in group 7. The ATP catabolism beyond 2 hours postmortem appeared less in group 2 compared with group 3 (3.58 ± 1.24 versus 0.39 ± 0.08 µmol/g dry weight for ATP and 3.03 ± 0.49 versus 7.64 ± 0.94 µmol/g dry weight for hypoxanthine at 24 hours, respectively; p < 0.05). Cadaver cooling significantly slowed ATP catabolism. Changes in ATP levels were similar in groups 2, 4, and 5.

Conclusions. These data suggest that in the non-heart-beating cadaver (1) cooling, ventilation, and inflation can delay ATP catabolism; (2) postmortem ventilation but not inflation for more than 2 hours will inhibit further ATP breakdown; (3) ventilation with either oxygen or cooled air is not more beneficial than room air ventilation; and (4) cold flush more than cadaver cooling will prevent ATP depletion.


    Introduction
 Top
 Footnotes
 Abstract
 Introduction
 Material and Methods
 Results
 Comment
 Acknowledgments
 References
 
See also page 240.

Lung transplantation, as other forms of solid organ transplantation, is limited by a scarcity of good donor organs. It is estimated that less than 10% of all available multiorgan donors have lungs suitable for lung transplantation [1]. With continued progress in organ transplantation the demand for transplants, and thus the need for organs, has increased markedly. The result is an increasing waiting time for a suitable organ and augmented risk of premature death of patients listed for lung transplantation.

To alleviate this critical organ shortage, there is a growing interest in increasing the potential donor pool by turning to alternative sources such as the use of living-related donors [2], partial (or lobar) transplants [3, 4], or the use of organs from circulation-arrested cadavers, so called non-heart-beating donors (NHBDs) [5].

In organs from such donors, cellular energy reserves present in the form of adenosine phosphates will become depleted very rapidly even after a short period of ischemia causing tissue and cellular damage. This might result in organ dysfunction jeopardizing the transplanted patient.

In previous studies performed in our laboratory, catabolism of adenine nucleotides was investigated in isolated rabbit lungs extracted after cold pulmonary flush with a crystalloid solution and immersed in saline solution at normothermia (37°C) up to 8 hours. These studies demonstrated that 15 minutes of warm ischemia will result in a significant decrease in adenosine triphosphate (ATP) levels and a concomitant increase in hypoxanthine (HYP) levels as the main catabolite [6, 7]. Inflation during normothermic ischemia resulted in a prolonged high ATP content, and the onset of anaerobic metabolism (reflected by lactate production) was related to the alveolar oxygen concentration during storage [8].

The current study was undertaken to investigate catabolism of adenine nucleotides in lung tissue remaining inside the cadaver left at room temperature after circulatory arrest. It was our aim to compare different methods to delay ATP catabolism and HYP formation in the NHBD.


    Material and Methods
 Top
 Footnotes
 Abstract
 Introduction
 Material and Methods
 Results
 Comment
 Acknowledgments
 References
 
Experimental Groups
Catabolism of adenine nucleotides in lung was studied at time intervals after death in six groups of animals (n = 6 in each group). Postmortem manipulation of the lungs inside the cadaver left at room temperature (24°C) differed between groups (Table 1Go): lungs left deflated (group 1 = control NHBD), lungs ventilated with room air (group 2), lungs inflated with room air (group 3), lungs ventilated with 100% O2 (group 4), lungs ventilated with cooled (4°C) room air (group 5), and lungs deflated and topically cooled with ice-cold (1°C) saline solution inside the cadaver submerged in an ice-bath (group 6). To compare catabolism of adenine nucleotides in isolated lungs preserved in the heart-beating donor by immediate flush via the pulmonary artery with a cold (4°C) crystalloid solution followed by ex vivo deflated storage in cold (1°C) saline solution, one more group of animals was added (group 7 = control heart-beating donor).


View this table:
[in this window]
[in a new window]
 
Table 1. . Time Interval Between Lung Biopsies in Different Experimental Groups
 
The decline in body and lung temperature of the animals in the groups 1, 5, 6, and 7 at time intervals after death forms the subject of a companion study [9].

Animal Preparation
All animals received humane care in compliance with the "Guide for the Care and Use of Laboratory Animals" published by the National Institutes of Health (NIH publication 85-23, revised 1985).

New Zealand white rabbits weighing 2.5 to 3 kg were premedicated and anesthetized by intramuscular injection with 0.25 mL/kg Imalgene (50 mg/mL ketamine; Rhône Mérieux, Lyon, France) and 0.15 mL/kg Domitor (1 mg/mL medetomidin-chlorhydrate + 1 mg/mL paramethylhydroxybenzoate + 0.2 mg/mL parapropylhydroxybenzoate; Orion Corporation, Farmos, Espoo, Finland). The animals were intubated with a 3.5-mm inner diameter cannula (Mallinckrodt Medical, Athlone, Ireland) via a cervical tracheostomy and the lungs were ventilated using a Harvard rodent ventilator model 683 (Harvard Apparatus, Inc, South Natick, MA) with room air (respiratory rate = 30 breaths/min; tidal volume = 10 mL/kg body weight; positive end-expiratory pressure = 2 cm H2O). Heparin Novo 700 IU/kg (sodium heparin 5,000 IU/mL; Novo Nordisk, Bagsvaerd, Denmark) was administered via a marginal ear vein. Rabbits were sacrificed by intravenous injection with 100 mg/kg Nembutal (60 mg/mL sodium pentobarbital; Abbott Laboratories, North Chicago, IL) resulting in cardiac arrest within 5 seconds and left at room temperature (24°C). In the group of animals with lungs deflated (group 1), the tracheal cannula was disconnected from the ventilator immediately after cardiac arrest. In the group with lungs ventilated (groups 2, 4, and 5), respiration was continued during the time interval with the same minute volume and positive end-expiratory pressure. In the group with lungs inflated (group 3), the tracheal cannula was clamped at end-tidal volume. In the group ventilated with cooled room air (group 5), a long coil of copper tubing submerged in ice was interposed between the ventilator and the tracheal cannula, reducing the temperature of inspiratory room air from 24°C to 4°C at the distal end of the cannula.

Fifteen minutes before the first biopsy, the chest was opened through a median sternotomy. Thymic tissue was excised. Both pleural cavities were opened. The sternal edges were reapproximated after each biopsy using towel clips. In group 6, both pleural cavities were filled once with ice-cold (1°C) saline solution immediately after sacrifice. Thereafter, the animal was completely submerged in an ice-bath preventing direct contact between the ice and the pleural cavity. In the group of animals with lungs preserved by immediate cold pulmonary flush (group 7), both superior caval veins, the inferior caval vein, the ascending aorta, and the main pulmonary artery were encircled by individual ligatures. The main pulmonary artery was cannulated through the right ventricular outflow tract using a 10-gauge cannula (Angiocath; Becton Dickinson Vascular Access, Sandy, UT). The pulmonary artery was isolated from the right ventricle by ligature around the tip of the cannula just distal to the pulmonary valve. The cannula remained in place for subsequent pulmonary flush. The tip of the left atrial appendage was transected to allow free drainage of the flush solution immediately after cardiac arrest. Both lungs were flushed by gravity at 60 cm H2O with 60 mL/kg cold (4°C) modified Krebs-Henseleit solution (composition in millimoles per liter: NaCl, 118; NaHCO3, 25; KCl, 5.6; CaCl2, 2.9; MgCl2, 0.6; NaH2PO4, 1.2; and D-glucose, 11; pH, 7.4; osmolarity, 321 mOsm/L). During the flush, the lungs were continuously ventilated with room air and topically cooled. Thereafter, the heart-lung block was excised and immersed deflated in cold (1°C) saline solution for 24 hours.

The whole procedure was carried out under clean but not sterile conditions.

Lung Biopsies
Small biopsy specimens of peripheral lung tissue were taken at time intervals after circulatory arrest for determination of adenine nucleotides (ATP, adenosine diphosphate [ADP], and adenosine monophosphate [AMP]) and their catabolites (inosine monophosphate, adenosine, inosine, and HYP). The biopsy specimens were immediately cooled in liquid nitrogen, lyophilized overnight, and further stored at -80°C until analysis.

In groups 1, 6, and 7 biopsy specimens were taken before cardiac arrest (preischemic levels). Further biopsy samples in different experimental groups were obtained at time intervals after death as listed in Table 1Go. In animals with lungs ventilated or inflated after death (groups 2 through 5), only two biopsy specimens were taken per animal to prevent postbiopsy air leak. The first biopsy specimen was taken from the left lung after one time interval (30, 120, or 480 min). Before this, the hilum of this lung was ligated and the contralateral lung remained inflated (group 3) or ventilated (groups 2, 4, and 5), reducing the tidal volume by half. The second biopsy specimen was taken from the right lung after the next time interval (60, 240, or 1,440 minutes, respectively).

Measurement of Adenosine Nucleotides and Catabolites
The adenine nucleotides and catabolites were measured by high-performance liquid chromatography as previously described [6]. We only focused on ATP, ADP, and AMP degradation and HYP formation as we have previously demonstrated that HYP is the main catabolite from adenine nucleotides in lung tissue, representing 92% of all nucleoside and purine base fraction at 4 hours of warm ischemia [6].

The level of total adenine nucleotides (TAN) was defined as the sum of ATP + ADP + AMP. Energy charge was calculated as (ATP + 0.5•ADP)/(ATP) + ADP + AMP) [10].

Statistics
Tissue levels of ATP, ADP, AMP, HYP, and TAN are expressed in micromoles per gram of dry weight (µmol/g dw). Data are presented as the mean ± standard error of the mean.

Differences within groups between premortem values and ischemic levels at successive time intervals after death were calculated using one-way analysis of variance with repeated measurements followed by Scheffé's multiple comparison test [11]. Differences between groups at the same postmortem time interval were compared using analysis of variance with factorial analysis (StatView SE+ Graphics [Abacus Concepts Inc, Berkeley, CA] on a Macintosh Performa 630 computer). Values of p less than 0.05 were accepted as significant (Scheffé's test).


    Results
 Top
 Footnotes
 Abstract
 Introduction
 Material and Methods
 Results
 Comment
 Acknowledgments
 References
 
Lung tissue levels of ATP, ADP, AMP, and HYP measured by high-performance liquid chromatography and calculated values for TAN in different experimental groups at time intervals after death are presented in Table 2Go.


View this table:
[in this window]
[in a new window]
 
Table 2. . Biochemical Data in Different Groups of Warm Ischemic Rabbit Lungsa
 
Breakdown of ATP and HYP formation in warm ischemic rabbit lungs left deflated at room temperature during 6 hours (group 1 = control NHBD) are depicted in Figure 1Go. There was a rapid decrease in ATP levels after circulatory arrest from 7.42 ± 0.40 µmol/g dw at 0 minutes (preischemic level) to 1.92 ± 0.44, 0.99 ± 0.11, and 0.80 ± 0.14 µmol/g dw at 30, 60, and 240 minutes, respectively (p < 0.01 starting at 20 minutes versus 0 minutes). Simultaneously, there was a transient increase in levels of ADP (0.97 ± 0.09 µmol/g dw at 0 minutes) and AMP (0.37 ± 0.04 µmol/g dw at 0 minutes) reaching a maximum at 10 min (1.78 ± 0.17 µmol/g dw) and 15 min (2.22 ± 0.55 µmol/g dw) respectively and slowly returning to pre-ischemic levels thereafter (see Table 2Go). A rapid and constant increase in HYP levels was noted from 0.12 ± 0.05 µmol/g dw at 0 minutes to 2.88 ± 0.27, 3.05 ± 0.56, and 3.60 ± 0.37 µmol/g dw at 60, 120, and 240 minutes, respectively (p < 0.05 starting at 60 minutes versus 0 minutes) (see Fig 1Go).



View larger version (22K):
[in this window]
[in a new window]
 
Fig 1. . Adenosine triphosphate (ATP) levels (filled circles) and hypoxanthine (HYP) levels (open circles) in rabbit lungs (n = 6) left deflated at room temperature (24°C) during 6 hours (group 1, control non-heart-beating donor). Mean tissue levels (±standard error of the mean) are expressed in micromoles per gram dry weight (µmol/g dw). (*p < 0.01 for ATP starting at 20 minutes versus 0 minutes; +p < 0.05 for HYP starting at 60 minutes versus 0 minutes by analysis of variance.)

 
In groups 2 through 6, an important decrease in ATP and TAN levels and concomitant increase in HYP levels were measured but these changes became significant versus preischemic values at longer time intervals after death when compared with group 1 (see Table 2Go). This indicates that postmortem ventilation (either with room air at 24° or 4°C or with 100% O2), inflation, and topical cooling of the lungs inside the cadaver can slow down catabolism of adenine nucleotides.

In contrast, ATP and HYP levels remained constant during 24 hours in deflated rabbit lungs cooled immediately after cardiac arrest by in situ cold (4°C) pulmonary flush followed by ex vivo storage in cold (1°C) saline solution (group 7 = control heart-beating donor) (Fig 2Go). Values for ATP and HYP were 7.77 ± 0.30 and 0.09 ± 0.02 µmol/g dw at 0 minutes versus 7.04 ± 0.66 and 0.37 ± 0.08 µmol/g dw at 24 hours, respectively (not significant for ATP at all intervals versus 0 minutes; p < 0.05 for HYP only at 24 hours versus 0 minutes).



View larger version (17K):
[in this window]
[in a new window]
 
Fig 2. . Adenosine triphosphate (ATP) levels (filled circles) and hypoxanthine (HYP) levels (open circles) in rabbit lungs (n = 6) flushed in situ with cold (4°C) Krebs-Henseleit bicarbonate buffer and stored deflated ex vivo in cold (1°C) saline solution for 24 hours (group 7, control heart-beating donor). Mean tissue levels (±standard error of the mean) are expressed in micromoles per gram dry weight (µmol/g dw). (NS = not significant for ATP versus 0 hour; ***p < 0.001 for HYP versus 0 hour by analysis of variance.)

 
The effect of 24-hour postmortem ventilation (group 2) and inflation (group 3) with room air on ATP, TAN, and HYP levels is depicted in Figure 3Go. Inflation with room air significantly delayed ATP levels at 1 hour compared with deflated lungs (group 1) (3.61 ± 0.65 versus 0.99 ± 0.11 µmol/g dw; p < 0.01) and appeared to be better, although not significantly better, than ventilation at this time interval (2.55 ± 0.49 µmol/g dw; not significant versus inflated, p < 0.01 versus deflated). This difference in ATP levels between inflation and ventilation disappeared at 2 hours (3.12 ± 1.44 and 3.51 ± 1.01 µmol/g dw, respectively) but the levels still remained higher in both inflated and ventilated lungs when compared with deflated lungs (1.13 ± 0.20 µmol/g dw). At longer time intervals the ATP level in inflated lungs returned to levels comparable with deflated lungs (1.99 ± 1.01, 1.21 ± 0.38, and 0.39 ± 0.08 µmol/g dw at 4, 8 and 24 hours versus 0.80 ± 0.14 µmol/g dw at 4 hours, respectively). Levels of ATP in ventilated lungs, however, further increased to 4.17 ± 0.83 µmol/g dw at 4 hours and remained at a constant level thereafter (3.17 ± 1.04 and 3.58 ± 1.24 µmol/g dw at 8 and 24 hours, respectively; p < 0.05 versus inflated at 24 hours) (see Fig 3Go). Energy charge also reincreased in ventilated lungs from 0.55 ± 0.05 at 1 hour to 0.73 ± 0.05 at 4 hours and thereafter remained constant up to 24 hours (0.73 ± 0.04). On the other hand, TAN levels in ventilated lungs remained fairly stable (6.63 ± 0.34, 6.30 ± 0.98 and 5.11 ± 1.45 µmol/g dw at 30 minutes, 4 hours, and 24 hours, respectively; not significant at all intervals versus preischemic levels). This is in sharp contrast with TAN levels in inflated lungs showing a constant decrease up to 24 hours (7.56 ± 0.37, 3.46 ± 1.07, and 1.07 ± 0.19 µmol/g dw at 30 minutes, 4 hours, and 24 hours; p < 0.05 at 2, 4, 8, and 24 hours versus 0 minutes). The differences in TAN levels between group 2 and 3 only were not significant until 24 hours (see Fig 3Go). The differences observed in HYP levels between ventilated and inflated lungs after 2 hours of warm ischemia are similar to the TAN plot, although this difference became significant at earlier intervals (p < 0.05 at 4, 8, and 24 hours) (see Fig 3Go).



View larger version (30K):
[in this window]
[in a new window]
 
Fig 3. . Adenosine triphosphate (ATP), total adenine nucleotides (TAN = ATP + adenosine diphosphate + adenosine monophosphate), and hypoxanthine (HYP) levels in rabbit lungs (n = 6) left at room temperature (24°C) during 24 hours comparing lungs ventilated with room air (group 2, filled squares) versus lungs inflated with room air (group 3, open squares). Mean tissue levels (±standard error of the mean) are expressed in micromoles per gram dry weight (µmol/g dw). (*p < 0.05, **p < 0.01, ***p < 0.001 for ventilated versus inflated; NS = not significant, +p < 0.05, ++p < 0.01, +++p < 0.001 for ventilated and inflated versus 0 hour by analysis of variance.)

 
Figure 4Go compares the effect on ATP catabolism, TAN levels, and HYP formation in deflated lungs of cadaver cooling (group 6) versus cold (4°C) pulmonary flush with Krebs-Henseleit bicarbonate buffer followed by ex vivo cold (1°C) storage (group 7) versus lungs left at room temperature (24°C) (group 1) during 4 hours. Topical cooling of deflated ischemic rabbit lungs inside the cadaver could significantly delay ATP depletion and HYP formation when compared with lungs left at room temperature (5.46 ± 1.32 versus 1.92 ± 0.44 µmol/g dw for ATP [p < 0.05] and 0.36 ± 0.14 versus 1.36 ± 0.19 µmol/g dw for HYP [p < 0.01] at 30 minutes, respectively). However, as expected, cold pulmonary flush was more effective and faster than topical cooling in blocking catabolism of adenine nucleotides after perfusion has stopped (p < 0.05 at 1, 2, and 4 hours for ATP, TAN, and HYP levels in group 6 versus group 7) (see Fig 4Go).



View larger version (37K):
[in this window]
[in a new window]
 
Fig 4. . Adenosine triphosphate (ATP), total adenine nucleotides (TAN = ATP + adenosine diphosphate + adenosine monophosphate), and hypoxanthine (HYP) levels in rabbit lungs (n = 6) left deflated during 4 hours comparing no cooling (room temperature, 24°C) (group 1, filled squares), topical cooling (1°C) of the cadaver (group 6, open circles), and cold (4°C) pulmonary flush followed by ex vivo deflated storage in cold (1°C) saline solution (group 7, open squares). Mean tissue levels (±standard error of the mean) are expressed in micromoles per gram dry weight (µmol/g dw). (*p < 0.05, **p < 0.01, ***p < 0.001 for topical cooling versus pulmonary flush by analysis of variance.)

 
Postmortem ventilation with either room air at 24°C (group 2), 100% oxygen (group 4), or cooled (4°C) room air (group 5) did not show any significant differences in ATP and TAN levels by multiple comparison test. Levels of HYP differed significantly in lungs ventilated with room air when compared with ventilation with 100% oxygen (1.17 ± 0.37 versus 2.87 ± 0.56 µmol/g dw at 2 hours [p < 0.05] and 3.03 ± 0.49 versus 5.88 ± 0.35 µmol/g dw at 24 hours, respectively [p < 0.001]).


    Comment
 Top
 Footnotes
 Abstract
 Introduction
 Material and Methods
 Results
 Comment
 Acknowledgments
 References
 
Rapid cooling of perfused organs by in situ flush with cold crystalloid solutions forms the basis of any solid organ preservation prior to transplantation [12]. Lungs preserved in this way can be transplanted safely after up to 6 to 8 hours of cold ischemia [13]. In the NHBD, however, there will always be a certain delay between (unexpected) circulatory arrest and the start of cold in situ flush of the organs. This critical time interval, so-called warm ischemia, will rapidly lead to tissue and cellular damage. This might result in organ dysfunction jeopardizing the transplanted recipient and remains the most difficult factor to overcome, especially after lung transplantation. Indeed, besides extracorporeal membrane oxygenation, no valid alternative organ replacement therapy is available nowadays in case of primary nonfunction of the pulmonary allograft.

The period of inevitable warm ischemia in the NHBD should therefore be kept as short as possible. However, organizing organ retrieval and obtaining family consent for organ donation consumes precious time. During this interval, organs have to be protected against cellular autolysis by preservation already inside the dead body.

Postmortem cardiac massage and continued ventilation of the cadaver until the onset of in situ cold flush through intraarterial catheters [14] or total body cooling on extracorporeal cardiopulmonary bypass [15] can protect the organs from NHBD during this time interval as already clinically demonstrated, albeit so far only in kidney [16] and liver [17] transplantation.

The clinical use of thoracic organs from NHBD is still anecdotal [5]. Nevertheless, transplantation of heart and lungs from NHBD is being investigated in an increasing number of animal experiments during recent years [1823].

The lung is unique among other solid organs in the way that oxygen can be delivered either through the airway or through its dual (bronchial and pulmonary) arterial circulation. Theoretically, the ventilated alveolar space provides a large oxygen reservoir for continued aerobic metabolism during prolonged storage. Gas exchange is a passive process, and cellular respiration can occur directly across the pulmonary gas interface. The energy requirements in the lung are primarily for the purpose of maintaining cellular integrity. To meet its energy demands, the lung almost exclusively metabolizes glucose [24].

In this study, we wanted to investigate catabolism of adenine nucleotides in lung tissue inside the cadaver left at room temperature after circulatory arrest using high-performance liquid chromatography. It was our aim to compare different methods to delay ATP catabolism and HYP formation in a rabbit model of NHBD. In a previous study from our laboratory, we already demonstrated a rapid decline in ATP content in normothermic deflated lungs (from a preischemic value [±standard deviation] of 9.42 ± 0.58 to 5.17 ± 0.86 µmol/g dw at 15 minutes and further to 3.42 ± 0.24 µmol/g dw at 30 minutes of normothermic ischemia) [6]. In the present study, ATP levels (±standard error of the mean) were lower both at 0 and 30 minutes of ischemia (7.42 ± 0.4 and 1.92 ± 0.44 µmol/g dw, respectively). In the previous study, however, lungs were ventilated and flushed with 60 mL/kg cold (4°C) Krebs-Henseleit bicarbonate buffer solution to remove all blood elements. The first lung biopsy specimen (preischemic value) was taken at the end of the flush (±2 minutes after the onset). Thereafter, the lungs were extracted and immersed deflated in saline solution at 37°C. A lung tissue temperature of 37°C was obtained after 5 minutes. In the present study, warm ischemia in deflated lungs started immediately after cardiac arrest. This difference in technique might explain the overall lower ATP levels in this study.

In a recent study, Bishop and colleagues [25] investigated the effect of in vivo pulmonary artery occlusion on ATP catabolism. They were able to demonstrate that combined pulmonary artery occlusion and lung collapse resulted in decreased ATP levels at 24 hours. This ATP decline was not observed in rabbits with either pulmonary artery occlusion or lung collapse alone, demonstrating that both ischemia and hypoxia are required for ATP depletion. The persistence of normal ATP content at 4 hours in rabbit lungs after combined pulmonary artery occlusion and lung collapse was attributed to the intact anastomotic bronchial circulation in vivo providing oxygen and substances for continued aerobic lung metabolism during a short period.

We compared ATP breakdown and TAN levels in room-air-ventilated (group 2) versus inflated (group 3) lungs and found that ATP breakdown was less in inflated lungs during the first hour but thereafter a further decline was observed only in inflated lungs. The differences, however, between these groups were not statistically significant until 24 hours. The fact that both TAN and HYP levels in group 2 remained fairly constant between 1 and 4 hours and the fact that ATP levels and energy charge reincreased during this same time interval suggests that ATP is regenerated from AMP and ADP by oxidative phosphorylation during postmortem oxygen ventilation. In contrast, TAN levels further decreased and HYP levels increased in group 3. This suggests that oxygen supply in nonperfused lungs inflated with room air is not sufficient for continued aerobic metabolism. In one of our previous studies [8], we already demonstrated that inflation with 100% O2 could prolong this period of preserved high-energy phosphate levels up to 4 hours before the onset of anaerobic metabolism as reflected by the formation of lactate. Identical observations were made by Akashi and associates [26] in rat lungs. The data observed in this study also confirm the findings in recent work by D'Armini and co-authors [27] in cadaveric rat lung. They nicely demonstrated that O2 ventilation of the nonperfused lung preserved adenine nucleotides and this correlated well with light microscopic pulmonary cell viability quantified by pulmonary artery infusion with trypan blue vital dye [27]. Ventilation with N2, however, was not associated with maintenance of ATP and TAN levels or with prolonged lung viability. This study suggests that not ventilation itself but continued oxygen supply is important to maintain aerobic metabolism and prevent cellular damage.

The biochemical data in our present study as well as in all the previously mentioned studies support the experimental findings in canine models that the duration of tolerable lung ischemia may be prolonged if the lungs remain ventilated or inflated during the ischemic interval [13, 19, 28].

We also investigated the effect of cooling on ATP metabolism. Both cadaver cooling (group 6) and cold pulmonary flush (group 7) will significantly delay ATP depletion, TAN degradation, and HYP formation when compared with lungs left at room temperature. As expected, cold pulmonary flush is more effective and faster than cadaver cooling in blocking ATP catabolism after cessation of circulation (p < 0.05 at 1, 2, and 4 hours for ATP, TAN, and HYP levels comparing group 6 versus group 7) (see Fig 4Go). These results are in accordance with the findings of Date and colleagues [29], who found that ATP levels in lungs inflated with 100% oxygen were stable for 18 hours after cold (4° or 10°C) pulmonary flush with low-potassium dextran and immersion in the same solution. The ATP level was significantly worse at 18 hours after preservation at 22°C [29]. Omote and associates [30] compared ATP concentrations in deflated rat lungs preserved in three different cold flush and storage solutions. Adenosine triphosphate content at 24 hours was significantly greater after preservation with University of Wisconsin solution when compared with Euro-Collins solution or low-potassium dextran.

We have found no significant difference in ATP and TAN levels between postmortem ventilation with either room air at 24°C (group 2), 100% O2 (group 4), or cooled (4°C) room air (group 5). In a companion study, we could not demonstrate a decline in lung temperature through ventilation with cooled air [9]. Therefore, we did not expect any more benefit from cooled air ventilation in delaying ATP breakdown. Levels of HYP at 24 hours differed significantly when comparing lungs ventilated with room air versus 100% oxygen. The ideal O2 concentration that should be administered to lung grafts during storage remains an open question [28].

From this study, we can conclude that in the NHBD (1) cooling, ventilation, and inflation can slow down ATP catabolism; (2) 24-hour postmortem ventilation but not inflation can inhibit further ATP breakdown and HYP formation beyond 2 hours of warm ischemia; (3) ventilation with either 100% O2 or cooled (4°C) air is not more beneficial than ventilation with room air; and (4) cold (4°C) crystalloid flush will immediately prevent ATP depletion and is more effective than cadaver cooling. Further studies are necessary to investigate whether lungs from human NHBDs will become a realistic alternative to expand the pulmonary donor pool.


    Acknowledgments
 Top
 Footnotes
 Abstract
 Introduction
 Material and Methods
 Results
 Comment
 Acknowledgments
 References
 
This work is supported by a grant from the "Nationaal Fonds voor Wetenschappelijk onderzoek - Levenslijn 1994" no. 7.0036.94 and partly by a grant from 3M Belgium.

We thank André Berghen, Peter Lemmens, Magda Mathijs, and Kanigula Mubagwa, MD, for expert technical and secretarial assistance.


    Footnotes
 Top
 Footnotes
 Abstract
 Introduction
 Material and Methods
 Results
 Comment
 Acknowledgments
 References
 
Presented at the Thirty-second Annual Meeting of The Society of Thoracic Surgeons, Orlando, FL, Jan 29-31, 1996.

Address reprint requests to Dr Van Raemdonck, Department of Thoracic Surgery, University Hospital Gasthuisberg, Herestraat 49, B-3000 Leuven, Belgium (E-mail: Dirk.VanRaemdonck{at}uz.kuleuven.ac.be).


    References
 Top
 Footnotes
 Abstract
 Introduction
 Material and Methods
 Results
 Comment
 Acknowledgments
 References
 

  1. Van Raemdonck D, Roels L, Verleden G, et al. Whence the lungs? Assessment of the use of lungs for transplantation from 156 consecutive donors. In: Cooper JD, Weder W, eds. Proceedings of the 3rd International Lung Transplant Symposium (Zurich, June 24-25, 1993), 1993:40.
  2. Cohen RG, Barr ML, Schenkel FA, DeMeester TR, Wells WJ, Starnes VA. Living-related donor lobectomy for bilateral lobar transplantation in patients with cystic fibrosis. Ann Thorac Surg 1994;57:1423–8.[Abstract]
  3. Bisson A, Bonnette P, Ben Al Kadi N, Leroy M, Colchen A. Bilateral pulmonary lobe transplantation: left lower and right middle and lower lobes. Ann Thorac Surg 1994;57: 219–21.[Abstract]
  4. Starnes VA, Barr ML, Cohen RG. Lobar transplantation: indications, technique, and outcome. J Thorac Cardiovasc Surg 1994;108:403–11.[Abstract/Free Full Text]
  5. D'Alessandro AM, Hoffmann RM, Knechtle SJ, et al. Successful extrarenal transplantation from non-heart-beating donors. Transplantation 1995;59:977–82.[Medline]
  6. De Leyn P, Lerut T, Schreinemakers H, et al. Adenine nucleotide degradation in ischemic rabbit lung tissue. Am J Physiol 1993;264:L329–37.[Abstract/Free Full Text]
  7. De Leyn P, Flameng W, Lerut T. Pattern of AMP degradation in ischemic rabbit lung tissue. J Invest Surg 1995;8:7–19.[Medline]
  8. De Leyn PRJ, Lerut TE, Schreinemakers HHJ, Van Raemdonck DEM, Mubagwa K, Flameng W. Effect of inflation on adenosine triphosphate catabolism and lactate production during normothermic lung ischemia. Ann Thorac Surg 1993;55:1073–9.[Abstract]
  9. Van Raemdonck DEM, Jannis NCP, Rega FRL, De Leyn PRJ, Flameng WJ, Lerut TE. External cooling of warm ischemic rabbit lungs after death. Ann Thorac Surg (in press).
  10. Atkinson DE, Walton GM. Adenosine triphosphate conservation in metabolic regulation. Rat liver cleavage enzyme. J Biol Chem 1967;242:3239–41.[Abstract/Free Full Text]
  11. Scheffé HA. A method for judging all contrast in the analysis of variance. Biometrika 1953;40:87–104.[Abstract/Free Full Text]
  12. Belzer FO, Southard JH. Principles of solid-organ preservation by cold storage. Transplantation 1988;45:673–6.[Medline]
  13. Kirk AJB, Colquhoun IA, Dark JH. Lung preservation: a review of current practice and future directions. Ann Thorac Surg 1993;56:990–1000.[Abstract]
  14. Lloveras J, Puig JM, Cerda M, et al. Optimization of in situ renal perfusion of non-heart-beating donors: four-lumen catheter developed for continuous perfusion pressure determination. Transplant Proc 1993;25:3169–70.[Medline]
  15. Valero R, Manyalich M, Cabrer C, Salvador L, Garcia-Fages LC. Organ procurement from non-heart-beating donors by total body cooling. Transplant Proc 1993;25:3091–2.[Medline]
  16. Wijnen RM, Booster MH, Stubenitsky BM, de Boer J, Heineman E, Kootstra G. Outcome of transplantation of non-heart-beating donor kidneys. Lancet 1995;345:1067–70.[Medline]
  17. Casavilla A, Ramirez C, Shapiro R, et al. Experience with liver and kidney allografts from non-heart-beating donors. Transplantation 1995;59:197–203.[Medline]
  18. Egan TM, Lambert CJ, Reddick R, Ulicny KS, Keagy BA, Wilcox BR. A strategy to increase the donor pool: use of cadaver lungs for transplantation. Ann Thorac Surg 1991;52:1113–21.[Abstract]
  19. Ulicny KS, Egan TM, Lambert J, Reddick RL, Wilcox BR. Cadaver lung donors: effect of preharvest ventilation on graft function. Ann Thorac Surg 1993;55:1185–91.[Abstract]
  20. Shirakura R, Matsumura A, Sueki H, et al. Viability of 24-hour preserved lung harvested from non-heart-beating donor by a multiorgan procurement method [Abstract]. J Heart Lung Transplant 1994;13:S63.
  21. Shimada K, Kondo T, Handa M, et al. The possibility of lung transplantation from non-heart-beating donors: experimental study in a canine model. Transplant Proc 1994;26:880–1.[Medline]
  22. Gundry SR, Fukushima N, Eke CC, Hill AC, Zuppan C, Bailey LL. Successful survival of primates receiving transplantation with "dead", non-beating donor hearts. J Thorac Cardiovasc Surg 1995;109:1097–102.
  23. Buchanan SA, DeLima NF, Binns OAR, et al. Pulmonary function after non-heart-beating lung donation in a survival model. Ann Thorac Surg 1995;60:38–46.[Abstract/Free Full Text]
  24. Date H, Matsumura A, Manchester JK, et al. Evaluation of lung metabolism during successful twenty-four-hour canine lung preservation. J Thorac Cardiovasc Surg 1993;105: 480–91.[Abstract]
  25. Bishop MJ, Holman RG, Guidotti SM, Alberts MK, Chi EY. Pulmonary artery occlusion and lung collapse depletes rabbit lung adenosine triphosphate. Anesthesiology 1994;80:611–7.[Medline]
  26. Akashi A, Nakahara K, Kamiike W, et al. Attenuation of warm ischemic injury of rat lung by inflation with room air: assessment of cellular components and the surfactant in the bronchoalveolar lavage fluid in relation to changes in cellular adenosine triphosphate. Transplantation 1993;55:24–30.[Medline]
  27. D'Armini AM, Tom EJ, Roberts CS, Henke DC, Lemasters JJ, Egan TM. When does the lung die? Time course of high energy phosphate depletion and relationship to lung viability after death. J Surg Res 1995;59:468–74.[Medline]
  28. Novick RJ, Menkis AH, McKenzie FN. New trends in lung preservation: a collective review. J Heart Lung Transplant 1992;11:377–92.[Medline]
  29. Date H, Lima O, Matsumura A, Tsuji H, d'Avignon DA, Cooper JD. In a canine model, lung preservation at 10 degrees is superior to that at 4 degrees C. A comparison of two preservation temperatures on lung function and on adenosine triphosphate level measured by phosphorus 31-nuclear magnetic resonance. J Thorac Cardiovasc Surg 1992;103:773–80.[Abstract]
  30. Omote Y, Ikeda K, Yamazaki K, Kubo Y. The superiority of UW solution for maintaining ATP concentrations during pulmonary preservation. Surg Today 1994;24:616–20.[Medline]

Related Article

Discussion
Ann. Thorac. Surg. 1996 62: 240-241. [Extract] [Full Text]



This article has been cited by other articles:


Home page
J. Thorac. Cardiovasc. Surg.Home page
T. Oto, A. Calderone, S. Pepe, G. Snell, and F. Rosenfeldt
High-flow endobronchial cooled humidified air protects non-heart-beating donor rat lungs against warm ischemia.
J. Thorac. Cardiovasc. Surg., August 1, 2006; 132(2): 413 - 419.
[Abstract] [Full Text] [PDF]


Home page
Ann. Thorac. Surg.Home page
F. R. Rega, A. P. Neyrinck, G. M. Verleden, T. E. Lerut, and D. E. M. Van Raemdonck
How long can we preserve the pulmonary graft inside the nonheart-beating donor?
Ann. Thorac. Surg., February 1, 2004; 77(2): 438 - 444.
[Abstract] [Full Text] [PDF]


Home page
PerfusionHome page
F. R Rega, E. J Vandezande, N. C Jannis, G. M Verleden, T. E Lerut, and D. E. Van Raemdonck
The role of leukocyte depletion in ex vivo evaluation of pulmonary grafts from (non-)heart-beating donors
Perfusion, January 1, 2003; 18(1_suppl): 13 - 21.
[Abstract] [PDF]


Home page
Am. J. Respir. Crit. Care Med.Home page
T. FUKUSE, T. HIRATA, T. NAKAMURA, M. KAWASHIMA, S. HITOMI, and H. WADA
Influence of Deflated and Anaerobic Conditions During Cold Storage on Rat Lungs
Am. J. Respir. Crit. Care Med., August 1, 1999; 160(2): 621 - 627.
[Abstract] [Full Text]


Home page
Eur. J. Cardiothorac. Surg.Home page
D. E.M. Van Raemdonck, N. C.P. Jannis, P. R.J. De Leyn, W. J. Flameng, and T. E. Lerut
Alveolar expansion itself but not continuous oxygen supply enhances postmortem preservation of pulmonary grafts
Eur. J. Cardiothorac. Surg., April 1, 1999; 13(4): 431 - 441.
[Abstract] [Full Text] [PDF]


Home page
Am. J. Physiol. Lung Cell. Mol. Physiol.Home page
T. Sakuma, K. Takahashi, N. Ohya, O. Kajikawa, T. R. Martin, K. H. Albertine, and M. A. Matthay
Ischemia-reperfusion lung injury in rabbits: mechanisms of injury and protection
Am J Physiol Lung Cell Mol Physiol, January 1, 1999; 276(1): L137 - L145.
[Abstract] [Full Text] [PDF]


Home page
Ann. Thorac. Surg.Home page
D. E. M. Van Raemdonck, N. C. P. Jannis, F. R. L. Rega, P. R. J. De Leyn, W. J. Flameng, and T. E. Lerut
Extended Preservation of Ischemic Pulmonary Graft by Postmortem Alveolar Expansion
Ann. Thorac. Surg., September 1, 1997; 64(3): 801 - 808.
[Abstract] [Full Text]


Home page
Ann. Thorac. Surg.Home page
D. E. M. Van Raemdonck, N. C. P. Jannis, F. R. L. Rega, P. R. J. De Leyn, W. J. Flameng, and T. E. Lerut
External Cooling of Warm Ischemic Rabbit Lungs After Death
Ann. Thorac. Surg., August 1, 1996; 62(2): 331 - 337.
[Abstract] [Full Text]


This Article
Right arrow Abstract Freely available
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Add to Personal Folders
Right arrow Download to citation manager
Right arrow Author home page(s):
Dirk E. M. Van Raemdonck
Filip R. L. Rega
Paul R. J. De Leyn
Willem J. Flameng
Right arrow Permission Requests
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Van Raemdonck, D. E. M.
Right arrow Articles by Lerut, T. E.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Van Raemdonck, D. E. M.
Right arrow Articles by Lerut, T. E.
Related Collections
Right arrowRelated Article


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
ANN THORAC SURG ASIAN CARDIOVASC THORAC ANN EUR J CARDIOTHORAC SURG
J THORAC CARDIOVASC SURG ICVTS ALL CTSNet JOURNALS