University of Wisconsin solution extends lung preservation after prostaglandin E1 infusion

Endothelium-dependent relaxation of canine pulmonary artery after prolonged lung graft preservation in University of Wisconsin solution: role of L-arginine supplementation

BACKGROUND

The University of Wisconsin (UW) solution has been demonstrated to enhance pulmonary allograft preservation. Endothelial nitric oxide (NO) production has been shown to be significantly impaired after ischemia and reperfusion (I/R) injury. The present experiments aimed to determine the protective effects of pulmonary endothelium-dependent function by using supplemental NO in University of Wisconsin (UW) solution following prolonged lung graft preservation.

METHODS

Thirty-six healthy mongrel dogs underwent thoracotomy to expose the left lung. In addition to a group given UW solution (n = 4), 100 micromol/liter l-arginine, (n = 7), 100 micromol/liter N(G)-monomethyl-l-arginine (l-NMMA n = 7) and 1.0 micromol/liter 3-morpholinosydnonimine (SIN-1, n = 18 respectively, were added to UW solution, and infused from the aortic root and pulmonary artery to the pulmonary vein. The perfused lung was then allowed to inflate to its maximum volume for 24-hour oxygenated preservation in each supplemented condition of UW solution at 4 degrees C. In the SIN-1 group, the preservation period was further divided into 8 hours and 16 hours, respectively. Rings of the third-order pulmonary artery of the inflated lung were then suspended in organ chambers to measure isometric force.

RESULTS

Endothelium-dependent relaxation (EDR) to acetylcholine, adenosine diphosphate and sodium fluoride of the pulmonary rings in the l-arginine group was significantly preserved compared with UW-solution-only group. The l-NMMA group showed significant EDR impairment after 24-hour preservation compared with the UW solution group. Similar to the l-arginine group, the SIN-1 group showed significant EDR protection with 8-hour preservation, but not with 24-hour preservation. In contrast, EDR to calcium ionophore A23187 showed no EDR changes after 24-hour preservation in any of the supplemented groups.

CONCLUSIONS

Supplemental l-arginine in UW solution ameliorates impaired pulmonary EDR following prolonged lung preservation of up to 24 hours.

Histopathological and immunohistochemical detection of protective effects of University of Wisconsin solution supplemented with iloprost on donor lung damage

OBJECTIVE

Histopathological evaluation and immunohistochemical markers of surfactant B and CD34 were used to detect alveolar type II cell and pulmonary endothelial cell damage in order to assess the efficacy on donor lung protection of University of Wisconsin (UW) solution supplementation with iloprost.

METHODS

Twelve rats were divided into two groups: UW solution was used alone in group I, and UW iloprost solution in group II. Lung samples were taken at regular intervals for pathological examination to evaluate alveolar cell integrity with hematoxylin and eosin staining. Preservation, of alveolar type II cell and pulmonary endothelial cells was assessed using surfactant B and CD34 immunomarkers, respectively.

RESULTS

In both groups, alveolar integrity, surfactant, and CD34 revealed time-dependent, progressive damage, although this deterioration was less apparent among the iloprost-supplemented group. Alveolar integrity was better preserved at 4, 6, 8, 12, and 48 hours among group II rate. Surfactant staining showed significantly more deterioration at 12 and 24 hours in group I. Similarly, CD34 demonstrated significantly more injury at 6, 12, 24, and 48 hours in group I.

CONCLUSION

Although progressive lung tissue damage assessed by histopathological and immunohistochemical methods was observed in both groups, our findings suggest less deterioration in the iloprost-supplemented group.

Alveolar liquid clearance and sodium channel expression are decreased in transplanted canine lungs

To determine the impact of transplantation-associated injury on the clearance mechanisms of pulmonary edema, we created a canine single lung transplant model. After 3 hours of preservation and 4 hours of reperfusion, right native lungs and left transplanted lungs were used to measure alveolar liquid clearance (ALC) in ex vivo liquid-filled lung preparations. We also examined the role of the pulmonary circulation in edema clearance in in vivo liquid-filled lungs between 4 and 8 hours of reperfusion. To study molecular modifications in ALC, we also measured expression levels of the epithelial sodium channel (ENaC) and sodium-potassium-adenosine triphosphatase (ATPase). We found that ALC was significantly lower in transplanted than in right native lungs ex vivo (p < 0.05) and that transplanted lungs did not respond to the beta-adrenergic agonist terbutaline. Our in vivo study confirmed the ex vivo results. Molecular analyses revealed that ENaC messenger RNA but not sodium-potassium-ATPase was significantly decreased in transplanted lungs (p < 0.01). Furthermore, there was a significant decrease in ENaC protein expression. Therefore, we conclude that the current investigation indicates that the lung injury caused by lung preservation and transplantation significantly reduces the edema clearance ability of transplanted lungs.

Ultrastructural damage to the preserved lung and its function after reperfusion

OBJECTIVE

This study was undertaken to clarify what damage to a lung during cold storage influenced the function of transplanted lung after reperfusion.

METHODS

We examined the ultrastructural damage in preserved right lung before reperfusion, and the function of transplanted left lung, in a same dog and measured the pulmonary artery oxygen pressure after reperfusion and the wet-to-dry-weight ratio. We compared these findings between those dogs that survived until six hours after reperfusion (Alive Group) and those dogs that did not survive (Dead Group). We also investigated any correlation between the ultrastructural damage in the preserved lung and the function of the transplanted lung.

RESULTS

The frequency of protrusion and destruction of the endothelial cells in the small pulmonary artery, and vacuolization of pneumocytes, in the Dead Group was significantly higher than that in the Alive Group. A correlation was found between the frequency of two kinds of ultrastructural damage; vacuolization in the endothelial cells in the small pulmonary artery and vacuolization in the pneumocytes, and the pulmonary artery oxygen pressure at 1-hour after reperfusion. A correlation was also found between the frequency of the vacuolization of pneumocytes and the wet-to-dry-weight ratio.

CONCLUSIONS

Findings suggested that a lung suffering severe damage to intracellular structure during hypothermic preservation is unable to function sufficiently after reperfusion and is at high risk for early graft failure.

Comparison of university of wisconsin, euro-collins, low-potassium dextran, and krebs-henseleit solutions for hypothermic lung preservation

OBJECTIVE

We sought to test the effectiveness of 4 different solutions for hypothermic rat lung preservation.

METHODS

One hundred ninety-two rats were used. The rats were divided into 4 groups, and University of Wisconsin, Euro-Collins, low-potassium dextran, or Krebs-Henseleit solution was used in each group. They were further divided into 6 subgroups of 8 rats each. The lungs were preserved at 4 degrees C for 0, 4, 6, 8, 12, or 24 hours, respectively, and lung function was studied by using a living rat perfusion model.

RESULTS

Pulmonary arterial flow decreased in each group after 4 to 6 hours of preservation; the low-potassium dextran group decreased the least and the Krebs-Henseleit group decreased the most. Pulmonary vascular resistance increased in each group after 6 hours of preservation; the Krebs-Henseleit group increased the most. Although airway pressure increased, static lung compliance and gas exchange capacity decreased after 8 hours of preservation; the Krebs-Henseleit group exhibited the worst values. Lung tissue wet/dry weight ratio increased gradually during preservation; the University of Wisconsin group exhibited the least increase. An ultrastructural study indicated the least morphologic changes in the low-potassium dextran group at 24 hours.

CONCLUSIONS

At 4 degrees C, all solutions preserved rat lungs for 4 hours with acceptable function. However, 6 hours of preservation resulted in damaged pulmonary function in some lungs, and this damage increased when preservation time was extended. The lungs preserved in low-potassium dextran solution had the best overall function, but the lungs preserved in University of Wisconsin solution had less edema.

Heart and lung preservation for transplantation

Since the beginning of transplantation the search for optimal means of organ preservation has been ongoing. One of the major causes of death early following heart or lung transplantation is graft failure. Factors that play a role in this problem include recipient and donor issues, but clearly procurement techniques and preservation solutions are important. This article summarizes the history, current clinical practice, and research devoted to heart and lung preservation for transplantation.

The role of inflammatory mediators in the mechanism of the host immune response induced by ischemia-reperfusion injury

Our previous study suggested that inflammatory mediators released due to IRI lead to host's immune response by upregulating MHC II in the host's peripheral T lymphocytes. This study hypothesized the role of platelet-activating factor (PAF) in the mechanism of induced MHC II upregulation due to IRI on peripheral T lymphocytes. The objectives of this study were to investigate the role of PAF in the induction of host immune reactivity and the protective effect of PAF-antagonist TCV-309 in combination with prostaglandin E1 (PGE1) against the host's immune response caused by IRI. Thirty female domestic swine were divided into three groups. Group A (6 donors, 6 recipients) had no pharmacological intervention. Group B (6 donors, 6 recipients) was the experimental group treated with TCV-309 + PGE1. Group C underwent sham operation. The ex vivo preservation time for groups A and B was 4 hr at 4 degrees C. To detect the changes in MHC II expression on T cells due to IRI, blood samples were collected before reperfusion (baseline level), 1, 2, and 3 days post-reperfusion. Two-colour flow cytometry analysis (FACS) was used to study MHC II-DR-beta expression in peripheral T lymphocytes. Swine anti-MHC II and anti-CD3 antibodies were used for this purpose. The FACS analyses demonstrated that in group A, there was a significant increase (p < 0.05) in MHC II intensity on peripheral T lymphocytes on day 2 post-reperfusion. By the third day post-reperfusion, MHC intensity had a tendency to decrease but did not reached the baseline level. In group B and C, however, there was no significant change in the level of MHC II in T lymphocytes at any of the post-reperfusion times. In group A, the number of CD3+MHC+ T lymphocytes significantly decreased (p < 0.05) by one day post-reperfusion and remained at this level until the third day post-reperfusion. In groups B and C, no significant change in the number of CD3+MHC+ T cells was observed. The results of this study suggested that the release of inflammatory mediators (e.g. PAF) due to IRI played a role in the mechanism of IRI-induced host's immune response. The results also suggested that the combination of TCV-309 + PGE1 could reduce this immune response.

Effects of preservation of rat lungs in a hypothermic medium on alveolar morphology

The increasing use of organs such as liver, lung, heart, pancreas, kidney and small intestine for transplantation purposes necessitates the development of optimum preservation techniques. The aim of our study was to investigate time-related morphological changes in alveoli during preservation of rat lungs in hypothermic Euro-Collins solution. Lungs were perfused via the pulmonary arteries with Euro-Collins solution at a temp of 19 degrees C. Totally perfused lungs were placed in Euro-Collins solution and stored for 6, 12 and 24 h at 4 degrees C. Biopsies were taken and prepared for examination at the light and electron microscopical level. Light microscopic examination revealed good preservation of the alveoli after storage for 6 h and moderate damage of alveolar architecture after 12 h of preservation. Severe degeneration of alveoli was found after 24 h of storage. The main ultrastructural changes were observed in lungs stored for 12 h and 24 h. After 6 h of storage, tissue damage was not found. Pneumocytes type II lost their apical microvilli and lamellar bodies were electron-lucent, indicating lamellar degeneration after 12 and 24 h of storage. Pneumocytes type I were also damaged. Their cytoplasm contained many vacuoles. Endothelial lining of the capillaries was contracted. Endothelial cells also showed many vacuoles. Edema around the capillaries was observed. We conclude on the basis of our morphological study, that Euro-Collins solution at low temperature is a good preservative for a short period of time only, but serious tissue damage occurs after periods of preservation longer than 12 h.

Calcium channel blocker enhances lung preservation

BACKGROUND

The standard program for lung transplantation employs PGE1 pretreatment for donor lungs, but its efficacy remains controversial. Calcium channel blocker has been reported more effective for reducing potassium-induced vasoconstriction. We investigate the efficacy of calcium channel blocker in the initial lung flush using rat lung transplant model.

METHODS

The excised rat lungs (n = 30) were flushed with either University of Wisconsin solution (UWS) with a prior injection of 50 microg/kg PGE1 into the pulmonary artery (UWS + PGE1; n = 7), UWS only (UWS; n = 7), or UWS containing 10(-6) M nifedipine (UWS + Nif; n = 8). After storage (4 degrees C) for 24 hours, all lungs were reperfused for 2 hours using an isolated, pulsatile blood perfused lung model. Control lungs (n = 8) were reperfused immediately after harvest. Blood gas analysis and shunt fraction, lung airway resistance, dynamic lung compliance, and pulmonary vascular resistance were assessed.

RESULTS

The pO2 at 30 minutes after reperfusion in the control, UWS, UWS + PGE1, and UWS + Nif group were 88.0 +/- 3.2, 49.6 +/- 2.2, 52.0 +/- 2.4, 85.1 +/- 2.1 (mmHg), respectively. Until 30 minutes after reperfusion, the pO2 in UWS and UWS + PGE1 group were significantly lower than those in UWS + Nif group (p < .001). Shunt fraction, lung airway resistance, and dynamic lung compliance also demonstrated the superiority of UWS + Nif group.

CONCLUSIONS

The early graft function after storage was significantly enhanced in lungs flushed with UWS containing nifedipine. Calcium channel blocker is more effective than PGE1 in reducing the potassium-induced vasoconstriction. Optimal composition of the flush may require both calcium channel blocker for pulmonary vasodilation and PGE1 for pulmonary protection by non-vasodilatory mechanisms.

Evaluation of new improved solution containing trehalose in free skin flap storage

BACKGROUND DATA

In this study, we evaluated a new intracellular type (IT-K) solution containing trehalose in a rabbit free skin flap storage model. Trehalose is a nonreducing disaccharide that can stabilise cell membranes under various stressful conditions.

MATERIAL AND METHOD

Seventy-two free skin flaps of the ear of rabbits were preserved in Euro-Collins (EC) solution or in IT-K solution for 24, 48, and 72 h at 4 degrees C. After completion of preservation, these flaps were replanted to the other ear by microsurgical techniques. Viability study and photo documentation were performed daily for 7 days. Tissue specimens were taken 24 h after vascular anastomosis, fixed in 10% formaldehyde and stained with haematoxylin and eosin (HE). Survival rates were analysed by Fisher's exact test for comparison of the two experimental groups. Values of P < 0.05 were considered to be statistically significant.

RESULTS

After 7 days, a survival rate of 100% of flaps were observed in both solutions after 24 h of preservation. After preservation for 48 h in IT-K solution the survival rate was 100%. However, in EC solution survival decreased to 75% (9 of 12 preserved flaps survived). This difference increased to 33.3% (4 of 12 flaps) in EC solution and 91.6% (11 of 12 flaps) (P < 0.01) in IT-K solution when the flaps were stored for 72 h. Light microscopic examination also showed less damage in flaps preserved in IT-K solution than in these preserved in EC solution.

CONCLUSION

IT-K solution was superior to EC solution in the preservation of free skin flaps on rabbit ears when stored for 48 and 72 h.

Studies of rat lung viability and adenine nucleotide metabolism after death

BACKGROUND

Prior studies from our laboratory have supported the use of cadaveric lungs for transplantation. In this study we investigated different preservation strategies for lungs retrieved from cadavers 4 hours after circulatory arrest.

METHODS

Seventy-two Sprague-Dawley rats were sacrificed and then ventilated with 100% oxygen for 4 hours. The lungs were then flushed with modified Euro-Collins, University of Wisconsin, or Carolina rinse solution, either alone, with prostaglandin E1, or with prostaglandin E1 plus the free radical scavenger dimethylthiourea. After an additional 4-hour cold storage, the left lung was flushed with trypan blue solution to quantify cell viability, whereas the right lung was used to determine wet-to-dry weight ratios and to measure the levels of the adenine nucleotides adenosine triphosphate, adenosine diphosphate, and adenosine monophosphate by high-performance liquid chromatography.

RESULTS

Viability was consistently better in the lungs flushed with Carolina rinse solution; these differences were statistically significant compared with those in the corresponding modified Euro-Collins subgroups (p < 0.005). The addition of prostaglandin E1 to all three preservation solutions improved the total adenine nucleotide levels; this increase was statistically significant for the modified Euro-Collins subgroup (p < 0.005). The total adenine nucleotide levels for the University of Wisconsin subgroups were higher than those for the corresponding modified Euro-Collins subgroups. The highest total adenine nucleotide levels were obtained in lungs flushed with Carolina rinse plus prostaglandin E1. Wet-to-dry weight ratios were always significantly lower in the lungs preserved with University of Wisconsin solution (p < 0.05), with a value similar to that of fresh tissue.

CONCLUSIONS

The characteristics of the solution used to flush and to store rat cadaveric lungs have an impact on lung viability and adenine nucleotide metabolism. The ideal preservation strategy may allow for lung retrieval from cadavers for safe transplantation.