Does University of Wisconsin solution harm the transplanted heart?

BACKGROUND: University of Wisconsin solution (UW) has been shown to be an effective preservative for the cardiac allograft. Recently, the high potassium content of UW has been implicated in causing coronary endothelial damage, allegedly contributing to development of cardiac allograft vasculopathy (CAV) and eventually to poorer survival. METHODS: We examined our experience using UW for preservation of cardiac allografts between 1990 and 1994 (n = 94), and compared these to hearts preserved with the lower potassium-containing Stanford solution used at our center between 1986 and 1990 (n = 65). Indices of graft function, ischemic injury, CAV incidence, CAV severity, and survival were evaluated. RESULTS: The 2 groups were similar in age, gender, diagnosis, donor inotropic support, donor-recipient weight ratio, incidence of acute graft failure, and cytomegalovirus seroconversion. UW-preserved hearts came from older donors (30.5 vs 24.1 years, p < .001), and were transplanted into more status 1 recipients (56% vs 22%, p < .001), consistent with current trends. Mean ischemic time of UW-preserved hearts was significantly longer (184 vs 155 minutes, p < .005) although time required to wean from bypass was less (45.5 vs 73.8 minutes, p < .001) and there was a trend towards less inotropic requirement. CPK-MB release was less with UW preservation (63 vs 87 microg/ dL, p = .001). Three years after transplantation, both groups were similar in the incidence of CAV (UW, 27.3%; STNF, 37.5%; p = 0.27), and also the severity of CAV (p = 0.78). Deaths attributed to CAV were equal in each group (UW, 11.4% vs STNF, 10.7%; p = 0.79). Kaplan-Meier survival analysis revealed equivalent survival curves (p = 0.26). CONCLUSIONS: We conclude that UW is a safe and effective myocardial preservative, allowing longer ischemic times with equivalent graft function. Our data suggest that when UW is used for cardiac allograft preservation, both CAV and survival are comparable to the experience with other preservatives containing lower concentrations of potassium.     

Preservation of donor livers with University of Wisconsin solution

The University of Wisconsin-solution extends the cold storage time of liver grafts over 20 hours. The early function is equal or better than with Eurocollins solution. Due to the extended preservation time, logistical advantages are present. However, deliberate extension of cold ischemia over the limit of 20 to 24 hours seems not yet indicated, since primary non-functioning grafts have a higher incidence after extended preservation.     

Comparison of Histidine-Tryptophan-Ketoglutarate and University of Wisconsin Preservation in Renal Transplantation

Histidine-tryptophan-ketoglutarate (HTK) is replacing University of Wisconsin (UW) solution as the preservation fluid for renal allografts in many centers, but recent large-scale data to support this transition are lacking. We conducted a retrospective analysis of patient and graft outcomes after renal transplantation at our center, comparing 475 consecutive living donor and 317 deceased donor transplants since the adoption of HTK with equal numbers of grafts preserved using UW solution. Data collected included donor and recipient age, race, sex, comorbidities and graft ischemia time. Graft and patient survival, as well as the incidence of delayed graft function (DGF), were studied by Kaplan–Meier and Cox regression analysis. No significant difference was seen in either patient or graft survival. Deceased donor kidneys in the HTK group had a higher incidence of DGF than the UW cohort, whereas this trend was reversed in the case of living donor organs. In multivariate analysis, HTK was associated with a significant risk reduction on the incidence of DGF. Prolonged preservation with HTK compared to UW was not associated with excess risk to the graft or patient. In summary, HTK demonstrated efficacy similar to UW in terms of patient and graft survival.     

Preservation of bone graft vascularity with the University of Wisconsin cold storage solution

The preservation of the microcirculation of bone has been evaluated with use of an in vitro canine tibia perfusion model. The production of relaxing factors by the osseous vascular endothelium was used as a metabolic marker for viability. This endothelial eccrine function was preserved for 5 days (120 h) by cold storage without continuous perfusion after a washout with the University of Wisconsin (UW) solution. This synthetic perfusate was superior to Krebs Ringer solution (p < 0.05), but storage without perfusion failed to prevent a significant rise in vascular resistance. Two techniques were effective for the preservation of bone vascularity for 24 h: washout with UW solution followed by nonperfusion cold (4°C) storage, and vascular washout with mannitol solution followed by continuous hypothermic (5°C) microperfusion (0.03 ml/min) with UW solution. The most consistent, and lowest, vascular resistance was produced by the microperfusion technique. However, UW solution does not consistently prevent an increase in vascular resistance with hypothermic ischemia. This technique may prove useful for the preservation of vascularized bone grafts, but it needs to be evaluated in a transplantation model.     

Continuous administration of pharmacological agents in heterotopically transplanted hearts

A modification of the intraabdominal heterotopic heart transplantation model in rats is described which enables the local administration of pharmacological agents by means of a mini osmotic pump. In this modification, the aortic arch of the donor heart is cut after junction of the left carotid artery to enable the introduction of a catheter in the innominate artery. This catheter is connected to an implantable mini osmotic pump which delivers a continuous flow for 7 days. Radiographs of transplanted animals bearing pumps filled with a contrast agent showed that the coronary vessels of the graft were effectively perfused. Furthermore, continuous perfusion of prednisolone into the graft appeared to be as effective as subcutaneous infusion. Additional information about the usefulness of this perfusion technique is provided by recent data indicating that the expression of MHC class II antigens on vascular endothelium of a graft could only be evoked by interferon-gamma when it was locally administered into the graft. Our results demonstrate that this technique is suitable for investigating the effects of local, continuous administration of pharmacological agents on heart grafts.     

Detection of acute cardiac rejection by analysis of heart rate variability in heterotopically transplanted rats.

BACKGROUND: A less-invasive method for cardiac allograft surveillance than endocardial biopsy is needed. We analyzed heart rate variability of heterotopically transplanted rat hearts as a method of detecting rejection of rat cardiac allografts. METHODS: Two kinds of heterotopic transplants were performed: 1) Brown-Norway rats received Brown-Norway rat isografts, and 2) Lewis rats received Brown-Norway rat allografts. The electrocardiogram (ECG) of the grafts were serially recorded under non-anesthetized and non-restricted conditions using a telemetric ECG transmitter implanted in the recipient's abdomen. Frequency domain analysis of the ECGs was performed using a fast Fourier algorithm. RESULTS: Total power of the heart rate variability in the isograft heart was reduced to 1.1%, compared to normal subjects without transplantation (p < .001). In the allograft heart, it was also reduced to 1.0% on days 1.5 (rejection score 0 to 1), but gradually increased thereafter up to 185% on day 6 (rejection score 3.75+/-0.50). The increase in spectral power was frequency-dependent (i.e., changes in the power in lower frequency range [LF, 0.04 to 0.67 Hz] were significantly higher than other ranges). This increase was reversible when immunosuppressive therapy was performed with the use of cyclosporine A. In the allograft group, peak-to-peak amplitudes of the QRS complex and heart rate were significantly decreased on day 5.5 or later, whereas the power of the LF was significantly increased by day 3.5 or later. CONCLUSIONS: Our data suggest that heart rate variability analysis is a promising noninvasive marker for early detection of cardiac allograft rejection. This method may also provide a sensitive means of assessing the effects of immunosuppressive therapy.     

Hemodynamic performance in a heterotopically transplanted dog heart: proposal of techniques for working left heart model of heterotopic (abdominal) heart transplantation.

To study hemodynamics together with various aspects of rejection after experimental heart transplantation, we developed a technique to produce a working left heart model of heterotopic (abdominal) heart transplantation. The interatrial septum and tricuspid valve of the donor heart are removed. The pulmonary arterial trunk, pulmonary veins, and inferior vena cava are ligated, and the stumps of the donor aorta and superior vena cava are anastomosed in an end-to-side fashion to the recipient abdominal aorta and inferior vena cava, respectively. Arterial blood from the recipient abdominal aorta thus perfuses the donor myocardium through the coronary artery, and the donor left ventricle receives venous blood from the recipient inferior vena cava as preload. In this model, the donor left ventricle does not pump out enough venous blood to desaturate the recipient femoral arterial blood but does generate approximately the same pressure as the recipient's heart. This model is reproducible, easy to manage, and can be applied to heterotopic heart transplantation in various experimental animals including rats.     

Biochemical changes in transplanted rat liver stored in University of Wisconsin and Euro-Collins solutions

BACKGROUND: Liver ischemia/reperfusion injury is a severe problem in transplantation, and preservation solutions could be critical for liver viability. The aim of our study was to evaluate the cytosolic and mitochondrial glutathione levels, the glyoxalase II activity, and the mitochondrial hydroperoxide contents of livers stored in different preservation solutions for 7 or 24 h and after transplantation. MATERIALS AND METHODS: Orthotopic liver transplantation was performed without reconstruction of the hepatic artery. The livers were stored at 4 degrees C for 7 or 24 h in University of Wisconsin or Euro-Collins solutions. Portions of livers before and after transplantation were homogenized and mitochondria isolated. RESULTS: Cytosolic glutathione levels were decreased in all stored livers and after transplantation. In livers stored with University of Wisconsin solution, mitochondrial glutathione was unchanged during cold storage and no significant decrease has been found after reperfusion, whereas in livers stored in Euro-Collins solution, mitochondrial glutathione was decreased and a further significant decrease was found 30 min after reperfusion. Mitochondrial hydroperoxides were higher in livers stored in Euro-Collins solution than in University of Wisconsin solution after 30 min of reperfusion. Mitochondrial glyoxalase II did not show any change by reperfusion. CONCLUSION: We have demonstrated that rat liver stored in Euro-Collins solution suffered a severe depletion of mitochondrial GSH and a concomitant increase of hydroperoxides. The data obtained suggested that the livers stored with University of Wisconsin solution were probably less prone to ischemia/reperfusion injury after liver transplantation.     

Preservation of the isolated canine heart in 4 degrees C air with intermittent infusion of a cardioplegic solution

The objective of this study is to determine whether intermittent infusions of cardioplegic solution has any effect on the isolated heart immersed in 4 degrees C saline. Further, in an attempt to prevent myocardial edema from developing during prolonged preservation, we stored the heart suspended in 4 degrees C air. In Experiment 1, 24 canine hearts were isolated after cardiac arrest induced by the infusion of 4 degrees C St. Thomas' Hospital Solution (STS). The isolated hearts were immediately immersed in 4 degrees C saline and divided into three groups (n = 8 in each group). The hearts were stored for 9 hours in 4 degrees C saline in Group 1 as well as in Group 2, however in the latter group intermittent infusions of STS were also given every 2 hours. In group 3, the hearts were suspended in 4 degrees C humidified air with intermittent infusions of STS every 2 hours. Intramyocardial pH showed a progressive fall in all 3 groups without significant difference in the rate of decrease among the groups (0.14/h in Group 1, 0.16/h in Group 2 and 0.13/h in Group 3, p less than 0.18). The ATP levels at 1 hour after excision were nearly the same in the three groups (about 25.9-26.3 micrograms/mg protein).(ABSTRACT TRUNCATED AT 250 WORDS)     

Comparison of University of Wisconsin and University of Pittsburgh solutions for heart transplantation

The effectiveness of University of Wisconsin (UW) and University of Pittsburgh (UP) solutions for the preservation of rat hearts was compared. Lewis rat hearts were preserved with UW (group A, n=45) or UP (group B, n=45) solution for 0 or 24 h and then transplanted heterotopically into the recipients' abdomen. Ten recipients in each group were observed to obtain 1-week graft survival rates. Tissue water content and tissue content of adenine nucleotides were measured 2 h after transplantation in six grafts from each group. Six hearts preserved for 0 h and seven hearts preserved for 24 h were taken from each group 24 h after grafting for histopathology. The 1-week graft survival rates of groups A24 and B24 were 60% and 10%, respectively. In the 24-h preserved grafts, adenosine triphosphate (ATP) and energy charge [(ATP+adenosine diphosphate/2)/(ATP+adenosine diphosphate+adenosine monophosphate)] of groups A and B were 0.972±0.165 and 0.200±0.123 mg/g wet tissue (P<0.05) and 74.4% and 61.1% (P<0.05), respectively. The tissue water content of group A24 was 71.7%, whereas that of group B24 was 74.1% (P<0.05). Histopathology revealed more severe muscle edema and necrosis and infiltration of polymorphonuclear cells in group B24 than in group A24. We conclude that UW solution is more appropriate for rat heart preservation than UP solution.     

Development of an in vivo ischemia-reperfusion model in heterotopically transplanted rat hearts

BACKGROUND: Heart transplantation has been extensively used in animal models, including studies on gene therapy for myocardial preservation. We investigated the feasibility of in situ left coronary artery (LCA) ligation as a physiological system for the examination of strategies to modulate myocardial tolerance against ischemia-reperfusion injury, such as gene therapy, using heterotopically transplanted rat hearts. METHODS: Lewis rat hearts that had been transplanted into syngeneic recipients' abdomens were subjected to 30-min ischemia, by occluding the LCA, and subsequent blood reperfusion by releasing the suture in situ (I/R group). Transplanted hearts in the sham group underwent laparotomy only. RESULTS: At 24 hr of reperfusion, the size of the ischemic region was 40.1+/-3.1% of the total left ventricular mass, and the infarct size was 47.5+/-3.3% of the area at risk in the I/R group. Cardiac function was reduced in the I/R group compared with the sham group, associated with higher myeloperoxidase activity (5.12+/-1.35 vs. 0.97+/-0.33 U/g wt) and higher incidence of apoptosis as defined by TUNEL (29.8+/-3.2 vs. 3.8+/-0.7%) and DNA ladder. In the I/R group, up-regulation of Bax, Bak, and caspase-3 was observed. CONCLUSIONS: These data on myocardial damage of transplanted hearts are consistent and equivalent to those of the usual LCA occlusion model, suggesting that this method is useful to investigate strategies for modulating myocardial tolerance against ischemia-reperfusion injury using heterotopically transplanted rat hearts in a more physiological blood-perfused model.     

A canine model to assess the electrical stability of the transplanted heart

The electrophysiological stability of the transplanted heart under conditions of myocardial ischemia is largely unknown. This problem was studied using a canine model of total cardiac denervation as a substitute for transplantation. Group 1 (N = 3) served as control with placement of ventricular pacing wires only. Group 2 (N = 3) underwent total cardiac denervation with placement of ventricular wires. Group 3 (N = 8) underwent total cardiac denervation with subsequent ligation of the left anterior descending coronary artery and collaterals to the apex. Group 4 (N = 9) underwent coronary artery ligation only. Chronic electrophysiological studies were conducted in all groups in the conscious state. Electrophysiological variables were determined from continuous Holter monitoring of the ECG, determination of strength-interval curves, and assessment of the inducibility of ventricular tachycardia by premature programmed pacing. In general, the denervated, infarcted group (Group 3) consistently demonstrated a greater level of electrical stability than the infarcted animals with normal innervation (Group 4).     

Effect of Prostaglandin E-1 on Wisconsin University and Histidine-Tryptophan-Ketoglutarate Preservation Solutions on Preservation Injury of the Perfused Liver

Background

The aim of this study was to investigate the effects of prostaglandin E-1 (PGE-1) on preservation injury in livers perfused with the University of Wisconsin (UW) or histidine-tryptophan-ketoglutarate (HTK) solutions.

Materials and methods

Five groups each including six rats included. Ringer’s lactate RL (group 1), HTK (group 2), HTK + PGE-1 (group 3), UW (group 4), or UW PGE-1 (group 5). Liver tissue and preservation fluid samples were obtained from the perfused lives for pathological and biochemical examinations respectively at 0, 6 and 12 hours.

Results

Upon biochemical examination, aspartate aminotrasnferase and alanine aminotransferase values were highest among the group with RL solution and lowest with PGE-1. Liver structure was found to be damaged immediately after RL solution, whereas it was preserved in the other four groups. Fewer cellular changes were reported at the end of 12 hours in the groups administered PGE-1 compared with the other groups.

Conclusions

PGE-1 when applied before preservation protected liver functions, decreased pathologic injury, and delayed changes that occur under cold ischemic conditions.     

Vascular and interstitial effect of University of Wisconsin solution on canine lung.

Belzer's University of Wisconsin cold storage solution (UWCSS) has proved useful in extending the shelf life of organs in extrathoracic transplantation and more recently has also been shown to be useful in heart transplantation. I investigated the effect of 4 degrees C UWCSS on the vascular and interstitial properties of the lung to see whether it affected the pulmonary microcirculation or caused pulmonary edema. Infusion of UWCSS was associated with a slight decrease in oxygen tension, but the final oxygen tension was no different from that previously demonstrated with Euro-Collins solution. Vascular conductance was not affected by UWCSS, but average vascular closure increased slightly, indicating that increased vascular tone occurs. This effect is similar to but less than that previously observed with Euro-Collins solution. Based on comparisons of wet to dry weight ratios, estimates of interstitial compliance, transvascular fluid flux, and microvascular filtration coefficient, it does not appear that UWCSS causes pulmonary edema. Further investigation into the usefulness of UWCSS in lung transplantation is therefore warranted.