Liver preservation with UW solution. I. Evidence that hydroxyethyl starch is not essential

Optimizing the concentration of hydroxyethylstarch in a novel intestinal-specific preservation solution

INTRODUCTION

Our lab has developed an effective nutrient-rich solution that facilitates energy production and control of oxidative stress during static cold storage of the intestine; however, the requirement for oncotic agents, such as hydroxyethylstarch (HES), has not been evaluated. This study investigated the effectiveness and requirement for HES in an intraluminal preservation solution during a clinically relevant period of cold storage.

METHODS

Rat intestines were procured, including an intravascular flush with University of Wisconsin solution followed by a 'back table' intraluminal flush with a nutrient-rich preservation solution containing varying amounts of HES (n=6 per group): Group 1, 0%; Group 2, 2.5%; Group 3, 5%; Group 4, 10%. Energetics, oxidative stress, and morphology were assessed over a 24h time-course of cold storage.

RESULTS

Overall, the 5% HES solution, Group 3, demonstrated superior energetic status (ATP and total adenylates) compared to all groups, P<0.05. Malondialdehyde levels indicated a reduction in oxidative stress in Groups 3 and 4 (P<0.05). After 12h, median modified Parks' grades for Groups 2 and 3 were significantly lower than Groups 1 and 4, P<0.05.

CONCLUSION

Our data suggests that when employing an intraluminal preservation solution for static organ storage, oncotic support is a fundamental requirement; 5% HES is optimal.

Efficacy of polyethylene glycols in University of Wisconsin preservation solutions: a study of isolated perfused rat liver

Recent reports argue that the performance of University of Wisconsin (UW) solution is limited by the presence of hydroxyethyl starch (HES) as an additive, since HES could be responsible for human red blood cell aggregation. We investigated the effect on rat liver preservation of replacing HES in UW solution by polyethylene glycols (PEG20 and PEG35) at two concentrations. An isolated perfused rat liver model was used. Six groups of preserved livers (n = 7 for each group) were compared to controls (nonpreserved livers, n = 7). The following preservation solutions were assayed: UW without oncotic supply, UW-HES (0.25 mmol/L), UW-PEG20 (0.03 and 0.25 mmol/L), and UW-PEG35 (0.03 and 0.25 mmol/L). After 24-hour cold storage, the livers were perfused for 120 minutes at 37 degrees C with oxygenated Krebs-Henseleit solution. During perfusion, transaminase release, portal and bile flows, and bromosulfophthalein (BSP) clearance were assessed. Results showed that the omission of oncotic supply in UW statistically increased ALT and AST release in perfusate and decreased bile and portal flows. PEG addition in UW solution, especially PEG35 at 0.25 mmol/L, effectively protected the rat liver graft from the onset of hypothermic ischemia/reperfusion damage. In conclusion, data reported here reveal that oncotic supply is essential for liver preservation and that HES can be effectively replaced by PEG in UW solution.

Effect of IGL-1, a new preservation solution, on kidney grafts (a pre-clinical study)

Ischemia-reperfusion injury conditions short-term and long-term graft function. The effects of the inversion of K+ and Na+ concentrations and substitution with polyethylene glycol for hydroxyethyl starch in University of Wisconsin (K-UW) solution were evaluated in isolated perfused rat kidneys and in autotransplanted pig kidneys. In the rat model kidneys were cold-stored for 24 h in K-UW or Na-UW or Na-PEG UW solutions (IGL-1 solution). Fractional sodium reabsorption and glomerular filtration rate was better in kidneys preserved in Na-UW and IGL-1 solution than those preserved in K-UW solution. In the pig model the left kidney was harvested and preserved in K-UW or IGL-1 solution for 24 h and then transplanted. In the autotransplanted pig model, kidneys preserved in IGL-1 solution showed a better function and a significant reduction of MHC class II expression, cellular apoptosis and interstitial fibrosis. In conclusion, kidneys preserved in IGL-1 solution tolerated ischemia/reperfusion injury better than those preserved in K-UW solution.

Preservation of mouse liver tissue during cold storage in experimental solutions assessed by x-ray microanalysis

The increasing use of organs for transplantation necessitates the development of optimal preservation techniques. The goal of this study was to investigate changes in elemental content in mouse liver cells during cold storage by x-ray microanalysis in parallel with morphologic studies. Tissue was stored at 4 degrees C for 4 to 12 hours in normal Krebs-Ringer solution (high sodium/potassium ratio), modified Krebs-Ringer solution (low Na(+)/K(+) ratio), Euro-Collins solution, University of Wisconsin (UW) solution, or seven modified versions of the UW solution. Incubation of liver in normal Krebs-Ringer solution caused a significant increase in sodium and decrease in potassium concentrations in contrast to incubation in other solutions. The concentration of sodium, potassium, and chlorine in the cells closely followed the concentration in the storage solution, indicating that the intracellular concentration of these ions during storage is entirely dependent on diffusion processes. The calcium concentration was independent of the storage solution used. Studies by light and transmission electron microscopy showed good preservation of hepatocytes after storage for 8 and 12 hours in UW solution and its variants, modified Krebs-Ringer solution and Euro-Collins solution, but showed moderate damage to mitochondria and swelling of the endoplasmic reticulum in normal Krebs-Ringer solution. In addition, damage to the sinusoidal endothelial cells was observed after 4 hours in normal Krebs-Ringer solution and after 8 to 12 hours in the other solutions. In conclusion, the only factor determining the intracellular concentration of diffusible ions after cold tissue storage is the ionic composition of the extracellular medium. X-ray microanalysis provides an objective method for assessing whether the intracellular ionic composition of tissue is maintained during storage.

Storage solution containing fructose-1,6-bisphosphate inhibits the excess activation of Kupffer cells in cold liver preservation

BACKGROUND

In liver transplantation, the activation of Kupffer cells at the time of cold preservation and reperfusion is considered to play an important role. In the present study, the usefulness of cold storage solution containing fructose-1,6-bisphosphate (FBP) was compared with University of Wisconsin (UW) solution in the function of Kupffer cells.

METHODS

Kupffer cells were separated from rat liver stored at 4 degrees C in each storage solution. Four kinds of storage solutions were used: UW, simplified UW without FBP (0-FBP), and solutions with 10 or 20 mM FBP (10-FBP, 20-FBP). Lipopolysaccharide (LPS) labeled by fluorescein was loaded after 12 or 24 hr of cold preservation in each solution. The rates of cells uptaking LPS as phagocytic ability were measured using flow cytometry. Tumor necrosis factor-alpha, cytokine-induced neutrophil chemoattractant, and nitric oxide (NO) were measured in the supernatant.

RESULTS

Tumor necrosis factor-alpha values in the 20-FBP group were significantly lower than those in the UW group. Cytokine-induced neutrophil chemoattractant values at 60 min after loading LPS were significantly lower in the 20-FBP group than in the UW group. NO values at 24 hr after loading LPS were significantly lower in the 20-FBP group compared with the UW group. The 20-FBP group was highest in the rates of cells uptaking LPS after 24-hr cold preservation.

CONCLUSIONS

The storage solution containing FBP controlled the secretion of cytokines and NO from Kupffer cells and maintained phagocytic ability. This solution was considered to be more useful than UW solution for Kupffer cell protection.

A preservation solution with polyethylene glycol and calcium: a possible multiorgan liquid

The addition of polyethylene glycol (PEG) to hepatocyte storage medium is known to decrease lipid peroxidation and swelling and to protect the cell cytoskeleton from cold. We therefore decided to investigate the effect of substituting PEG for hydroxyethyl starch (HES) in an extracellular-like UW solution, with and without Ca++, on rat liver preservation. Isolated perfused rat livers were used to assess graft injury after 24h of cold storage. Four groups of preserved livers ( n=6 for each group) were compared to controls (non preserved livers, n=11). For this purpose, Belzer solution (K+-UW, group 1) was stepwise modified. Group 2 (Na+-UW) was treated with the same liquid, however with inverted concentrations of Na+ and K+. Group 3 was preserved in the first experimental solution (EPS-1) with Ca++ (0.5mM) added to the Na+-UW solution. In the EPS-2 (group 4), PEG-35 (0.03mM) was substituted for HES. The last group, EPS-3 (group 5) was treated with the same compounds as EPS-2, but without Ca++. After 24h of cold storage and 120min normothermic reperfusion, there was no statistical difference in transaminases (ALT and AST) release between the control and the Na+-UW groups. Furthermore, rat livers preserved in Na+-UW solution released less ( P<0.05) ALT and AST and excreted more ( P<0.05) indocyanine green (ICG) than livers preserved in K+-UW solution. The addition of 0.5mM Ca++ to Na+-UW solution (EPS-1) dramatically increased ( P<0.05) parenchymal (ALT, AST) and non parenchymal (creatine kinase-BB) cellular injury. The substitution of PEG (0.03mM) for HES (EPS-2) reduced ( P<0.05) membrane injuries due to Ca++ while bile flow was statistically increased ( P<0.05). Finally, the omission of Ca++ from EPS-2, that is EPS-3, has no statistically significant effect on the studied parameters. PEG effectively protected the rat liver grafts from the onset of hypothermic ischemia-reperfusion and Ca++ damages and thus may be a valuable additive to preservation solutions.

Comparison of Celsior and UW solution in experimental pancreas preservation

BACKGROUND

The University of Wisconsin solution (UW) is the gold standard for pancreas preservation. Celsior (CEL) was formulated specifically for heart preservation. Recently, experimental and clinical experience has been reported on the application of CEL to abdominal organs. In this animal study, pancreas preservation with CEL was compared with that in UW solution.

PATIENTS AND MATERIALS

Heterotopic, allogeneic pancreaticoduodenal transplantation was performed in female Göttingen Minipigs (n = 12 donors, n = 12 recipients). The grafts were flushed and stored for 6 h at 4 degrees C in UW or CEL. The recipients were randomized into two groups receiving either UW (n = 6)- or CEL (n = 6)-preserved grafts with a follow-up of 5 days. Blood flow (laser Doppler), partial oxygen tension, histological changes, endothelin-1 (plasma, immunohistochemistry), lipase, amylase, trypsinogen activation peptide, and C-reactive protein (CRP) were measured.

RESULTS

Partial oxygen tension was lower in the CEL group (P < 0.05). However, blood flow did not differ between UW- and CEL-preserved organs. The histomorphologic analysis of the pancreatic grafts revealed significantly less edema in the UW-preserved organs. Serum levels of amylase, lipase, CRP, and TAP taken from the central venous blood were comparable in the two groups, except for higher amylase values 36 h after reperfusion in the CEL group compared to the UW group (P < 0.05). Likewise, TAP taken from the portal venous effluent of the graft was found to be higher in the CEL group than in UW (P < 0.05). Endothelin-1 serum levels rose significantly during reperfusion without differences between the two groups. ET-1 immunohistochemistry revealed increased local ET-1 during reperfusion in all grafts. However, the ET-1 immunostaining in the CEL group was more pronounced than that in the UW group (P < 0.05).

CONCLUSIONS

Our results suggest that CEL solution is not as effective in preventing pancreatic ischemia/reperfusion damage as the standard UW solution in experimental pancreas transplantation. Increased ET-1 immunostaining and reduced p(ti)O(2) in the CEL group indicate increased microcirculatory damage in the CEL group.

Effects of hypothermic machine perfusion on rat liver function depending on the route of perfusion

BACKGROUND AND METHODS

The aim of this study was to evaluate the efficacy of hypothermic machine perfusion (HMP) to preserve rat livers according to the route of perfusion, i.e., via portal vein, hepatic veins (retrograde), or hepatic artery. Livers were preserved for 24 or 48 hr by simple cold storage (SCS) or by HMP. Preservation solution was supplemented with (HMP) or without (SCS) hydroxyethyl starch. After preservation, grafts were reperfused for 2 hr with an oxygenated Krebs-Henseleit bicarbonate buffer.

RESULTS

After 24 hr of preservation, total glutathione concentrations in HMP livers were similar (1287+/-37, 1418+/-118, and 1471+/-62 nmol/g in hepatic artery, portal vein, and hepatic vein HMP livers, respectively) and higher than in the SCS (833+/-118 nmol/g, P<0.05) group. These higher total glutathione values were due to higher reduced glutathione concentrations. ATP concentrations in the liver tissue were similar in HMP groups (0.75+/-0.4, 0.64+/-0.1, and 0.77+/-0.1 micromol/g in hepatic artery, portal vein, and hepatic vein HMP livers, respectively) and higher than in SCS (0.32+/-0.06 micromol/g, P<0.05). After 2 hr of normothermic reperfusion, bile production in the HMP portal and HMP retrograde groups were similar (391+/-29 ml and 372+/-25 ml) and higher than in the HMP artery or SCS groups (275+/-25 ml and 277+/-32 ml, respectively; P<0.05). Aspartate transaminase, alanine transaminase, lactate dehydrogenase, and purine nucleoside phosphorylase release into the perfusate of HMP portal and HMP retrograde perfused livers was similar and significantly lower compared to the HMP artery and SCS groups. At the end of reperfusion, no statistical differences were found for glutathione concentration and energetic reserves in the livers of each group. After 48 hr of preservation, livers from the HMP portal and HMP retrograde groups did significantly better than livers from the HMP artery or SCS groups.

CONCLUSIONS

This study confirms the superiority of HMP over SCS to preserve the liver graft. It shows that retrograde perfusion is similar to PV perfusion and that perfusion by HA is less beneficial.

Role of Kupffer cells in the survival after rat liver transplantation with long portal vein clamping times

Applying the orthotopic rat liver transplantation (ORLT) model, postoperative survival has been shown to be mainly dependent on the portal vein clamping time (PVCT). It was hypothesized that prolonged intestinal congestion was responsible for the activation of Kupffer cells (KC) with overproduction of TNF, secondary to splanchnic endotoxin accumulation and release on reperfusion. The role of KCs was directly investigated in the context of long PVCTs by eliminating them (using liposome-encapsulated dichloromethylene diphosphonate), by preventing their activation (using a calcium channel blocker, nisoldipine) and by inhibiting TNF production (using thalidomide). Livers from different groups of rats were transplanted following 24-h cold preservation in the UW solution with long PVCTs (from 18-21 min). KCs depletion, preservation with nisoldipine and pretreatment with thalidomide significantly improved survival in conditions using long PVCTs. KC depletion and nisoldipine preservation had no effect on liver enzymes or pathological findings while lung injury was significantly improved. The present data confirm that, in the context of ORLT with long PVCTs, KCs are directly responsible for the systemic endotoxin-like shock syndrome and their effect is mediated through overproduction of TNF.

Liver preservation: a comparison of celsior to colloid-free University of Wisconsin solution

INTRODUCTION

Celsior (CEL) was formulated specifically for heart preservation. Recently some preliminary reports have suggested that CEL is also effective for liver preservation. In this study liver preservation with CEL was compared to colloid-free University of Wisconsin solution (MUW).

METHODS

Arterialized rat liver isografts were flushed and stored for 24 hr at 0 degrees C in CEL or MUW before orthotopic transplantation. Plasma albumin, bilirubin, glucose, aspartate aminotransferase, and alkaline phosphatase were measured 1, 2, 3, 7, 14, 21, and 28 days after surgery.

RESULTS

All recipients of MUW-preserved livers survived, none of the recipients of CEL-preserved grafts lived beyond 3 days. On day 1, AST was raised in all rats but rats receiving CEL-preserved liver grafts were also markedly hypoglycemic, hypoalbuminemic and had elevated alkaline phosphatase.

CONCLUSION

Celsior is not an effective solution for long-term liver preservation in its present composition.

Pharmacologic graft protection without donor pretreatment in liver transplantation from non-heart-beating donors

BACKGROUND

Non-heart-beating donors (NHBDs) are considered potential sources of transplant organs in an effort to alleviate the problem of donor shortage in clinical liver transplantation. We investigated the possibility of pharmacologic protection of hepatic allograft function from NHBDs without donor pretreatment.

METHODS

Orthotopic liver transplantation was performed using pigs. In donors, cardiac arrest was induced by stopping the respirator. Forty-five minutes after cessation of the respirator, the liver was flushed with cold lactated Ringer's solution including heparin and with the University of Wisconsin (UW) solution, and then preserved for 8 hr at 4 degrees C in the UW solution. The pigs were divided into two groups: a control group and a treated group. In the treated group, an endothelin antagonist TAK-044 was added to the UW solutions (10 mg/L), and TAK-044 (10 mg/kg body weight) and a platelet activating factor antagonist E5880 (0.3 mg/kg body weight) were also administered to the recipients.

RESULTS

TAK-044 and E5880 treatment significantly increased the 7-day survival rate of the recipients (100% vs. 17%, P<0.05). In the treated group, portal venous pressure immediately after reperfusion of the graft was significantly lower than in the control group, and postoperative increase in serum concentrations of glutamic oxaloacetic transaminase and total bilirubin was attenuated. Moreover, the energy charge and adenosine triphosphate concentration of the liver were rapidly restored after reperfusion.

CONCLUSIONS

Pharmacologic modulation with TAK-044 and E5880 avoiding donor pretreatment can improve the viability of hepatic allografts procured from NHBDs.

An endothelin receptor antagonist ameliorates injuries of sinusoid lining cells in porcine liver transplantation

BACKGROUND

TAK-044 is an endothelin receptor antagonist. Whether the agent has protective effects on liver graft injuries from non-heart-beating donors is unknown.

METHODS

In donor pigs, cardiac arrest was induced by stopping the respirator. Forty-five minutes after cessation of the respirator, the liver was flushed with University of Wisconsin (UW) solution, preserved for 8 hours at 4 degrees C, and transplanted orthotopically. The pigs were divided into two groups: a control group and a drug-treated group in which TAK-044 was given in the UW solutions (10 mg/L) and was administered to recipients (10 mg/kg body weight).

RESULTS

TAK-044 treatment significantly increased recipient survival rate. After reperfusion of the graft, portal venous pressure and 15-minute retention rate of indocyanine green were significantly reduced in the drug-treated group. Electron microscopic findings indicated that TAK-044 attenuated endothelial cell injuries.

CONCLUSION

TAK-044 treatment improves the viability of livers harvested from non-heart-beating donors. The main effect of the agent is protection of endothelial cells from ischemia/reperfusion injuries.

Decreased survival in rat liver transplantation with extended cold preservation: role of portal vein clamping time

Primary liver graft dysfunction is currently related to cold ischemia-reperfusion injury, although a wide survival range has been reported using 24-hour preservation in cold University of Wisconsin (UW) solution. We hypothesized that the portal vein clamping time (PVCT) played a more important role than cold preservation injury in the postoperative outcome. Rat liver transplantation was performed using different clamping times after 24-hour cold ischemia in the UW solution. Survival rates, plasma tumor necrosis factor (TNF), and nitrate/nitrite levels were examined. Subsequently, the effect of clamping time was evaluated on hepatocyte and sinusoidal endothelial cell (SEC) function using isolated perfused livers. Survival rate was directly related to clamping time length. Marked increases in TNF and nitrate/nitrite levels were found after surgery, particularly after long clamping times. In perfusion studies, the SEC function was already markedly altered after preservation alone and was not further modified by transplantation. By contrast, the hepatocyte function was moderately altered after transplantation, irrespective of clamping times, even when rats operated with long clamping times were in terminal conditions. In rats, 24-hour preservation in cold UW solution is not a severely compromising condition leading to primary liver nonfunction. Long PVCTs are associated with an endotoxemia-like syndrome more related to a warm intestinal ischemia than to cold ischemia injury of the liver.

Hypothermic ischaemia of the liver: a re-perfusion phenomenon

BACKGROUND

The effects of hypothermic injury to the liver were investigated on an isolated perfusion circuit by comparing porcine livers with varying degrees of preservation injury.

METHODS

A group of unstored livers (n = 5) were compared to livers stored in University of Wisconsin (UW) solution for 18 h (n = 5), and a group of livers stored in Hartmann's solution for 18 h (n = 5).

RESULTS

We observed that the degree of platelet sequestration was directly related to the severity of the preservation injury. After 2 h of isolated liver perfusion, the perfusate platelet count fell from 148 +/- 14 x 10(9)/L to 84 +/- 13 x 10(9)/L for control livers. In comparison for livers stored in UW solution, the platelet count fell from 173 +/- 43 x 10(9)/L to 61 +/- 14 x 10(9)/L representing a 64.8% fall, while for those stored in Hartmann's solution, an even more profound fall from 152 +/- 36 x 10(9)/L to 19 +/- 9 x 10(9)/L (87.5% fall) was observed. The difference between the UW-stored and Hartmann's-stored livers was significant (P < 0.05). However, using this model, the degree of leukocyte sequestration did not differentiate the groups. Both histological and ultrastructural examination of liver biopsies taken immediately following revascularization demonstrated that for mild degrees of preservation injury following hypothermic storage, changes occur to the sinusoidal lining cells well before changes to the parenchymal elements.

CONCLUSIONS

These findings substantiate the hypothesis that the primary injury associated with hypothermia involves the sinusoidal lining cells (non-parenchymal elements), that it is predominantly a reperfusion phenomenon and that efforts at improving preservation should therefore be targeted primarily at these cells and not the hepatocytes.

Comparison of UW solution and St. Thomas' solution in the rat: importance of potassium concentration

BACKGROUND

University of Wisconsin solution (UW) is in limited clinical use for heart transplantation, but there are doubts about its efficacy and concerns about the effect of its high K+ concentration on endothelium. St. Thomas' solution with or without aspartate is widely used and is of proven efficacy.

METHODS

Using a modified (starch-free) variant of UW (MUW) we studied: (1) recovery of function with UW compared with aspartate-containing St. Thomas' solution; (2) effect of elevation of K+ in St. Thomas' solution to the level in UW; and (3) effect of reduction of K+ in UW and addition of Ca2+ or aspartate. Isolated rat hearts underwent 7 hours of arrest at 1 degrees C using MUW with or without 20 mmol/L aspartate or using aspartate-containing St. Thomas' solution.

RESULTS

Functional recovery with MUW (51.8% +/- 2.5%) was superior to that with aspartate-containing St. Thomas' solution (37.1% +/- 4.3%; p < 0.01). Addition of aspartate to MUW had no effect. During 6 hours of arrest, lowering the K+ in MUW from 125 mmol/L to 20 mmol/L reduced functional recovery from 59.9% +/- 4.2% to 42.3% +/- 4.3% (p < 0.01). The addition of 1 mmol/L Ca2+ had no effect. Elevation of K+ in St. Thomas' solution produced more rapid arrest but no improvement in recovery.

CONCLUSIONS

The protective effect of starch-free UW is greater (+13%) than that of aspartate-enriched St. Thomas' solution. Reduction of K+ in UW to lessen possible deleterious effects would decrease its protective effect by about 30% to a level comparable with that of St. Thomas' solution.

A novel dextran 40-based preservation solution

Although the University of Wisconsin (UW) solution has become the standard solution for the preservation of kidneys for transplantation, the importance of the colloid hydroxyethylstarch (HES), one of the key compounds of the UW solution, has been questioned repeatedly. It is now established that HES is not necessary for routine kidney preservation. However, colloids may still be advantageous in UW like solutions for the purpose of multiorgan procurements and the preservation of organs from marginal donors. It has been shown in various experimental models that dextran 40 may successfully substitute for HES. Dextran 40 is not only cheaper but also has a variety of biological effects that may be beneficial during the graft reperfusion phase. The aim of this clinical study was to examine the efficacy of a dextran 40-based preservation solution (Dex-PS) for its use in human kidney graft preservation and to compare the transplantation results with kidneys preserved with UW solution. A total of 87 kidneys were preserved with Dex-PS and matched with 87 kidneys preserved with UW solution. Both groups were comparable in terms of donor and recipient characteristics and both had a high proportion of kidneys from nonheart-beating donors. Patient survival and graft survival after 1 year were 95% and 86% for the Dex-PS group and 94% and 90% for the UW group, respectively (P = NS). Primary nonfunction, delayed graft function, postoperative need for dialysis, and follow-up of serum creatinine were statistically comparable between these two groups. We conclude that dextran 40 can safely replace HES in UW solution for the purpose of clinical kidney preservation. There were no statistically detectable differences in graft performance between the kidneys preserved with UW and those preserved with Dex-PS.

Effects of taurine on liver preservation in UW solution with consecutive ischemic rewarming in the isolated perfused rat liver

Taurine (2-aminoethane sulfonic acid) is a physiologic amino acid involved in cellular osmoregulation in various species including man. This study was intended to compare the respective effects of cold storage and consecutive ischemic rewarming of the liver postischemic hepatic flow and hepatocellular outcome upon reperfusion with or without the addition of taurine to the preservation medium. Livers from male Wistar rats were rinsed free of blood via the portal vein and stored ischemically at 4 degrees C in UW solution. Livers from group 1 were then rinsed again with 10 ml Ringer's solution and reperfused with Krebs-Henseleit buffer at a constant pressure of 10 mmHg for 45 min at 37 degrees C in a nonrecirculating manner. Livers from groups 2 and 3 were subjected to 30 min of warm ischemia subsequent to cold storage and prior to reperfusion with 10 mM taurine added to the UW solution in group 3. While there were only very few signs of hepatic injury in group 1, the additional period of warm ischemia (group 2) led to a significant reduction in early perfusate flow and enhanced enzyme leakage from the livers during postischemic rinse and reperfusion. Livers in group 3 exhibited an amelioration in hepatic circulation and significantly reduced enzyme release as compared to group 2. The results clearly demonstrate a remarkable impact of postischemic rewarming on graft viability. Furthermore, the addition of taurine to the preservation medium was shown to improve hepatic circulation and enhance viability of the liver upon reperfusion.

Role of Kupffer cells in cold ischemia/reperfusion injury of rat liver

BACKGROUND & AIMS

Kupffer cell activation is hypothesized to play an etiopathogenic role in storage-related graft failure after liver transplantation. The aim of this study was to verify whether the elimination of Kupffer cells modifies the magnitude of cold ischemia/reperfusion injury of the liver.

METHODS

Rat Kupffer cells were eliminated by an intravenous injection of liposome-encapsulated dichloromethylene diphosphonate. Livers from control and treated rats were isolated and perfused before and after 24-hour cold ischemia in the University of Wisconsin solution (4 degrees C). Hepatocyte and sinusoidal endothelial cell functions were evaluated by taurocholate and hyaluronic acid elimination, respectively. Liver transplantation was also performed using control and treated donor livers stored under identical conditions.

RESULTS

Compared with baseline values, similar alterations were found in both groups after cold ischemia for hepatocyte function (intrahepatic resistance, bile secretion, lactate dehydrogenase release, oxygen consumption, and taurocholate intrinsic clearance) and for sinusoidal endothelial cell function (hyaluronic acid intrinsic clearance). The 10-day survival rate of animals undergoing transplantation was not different between the groups (6 of 15 vs. 4 of 15, control vs. treated donor livers, respectively).

CONCLUSIONS

The presence or absence of Kupffer cells does not modify the effect of 24-hour cold ischemia/reperfusion on the rat liver.

Effects of taurine on liver preservation in UW solution with consecutive ischemic rewarming in the isolated perfused rat liver

Taurine (2-aminoethane sulfonic acid) is a physiologic amino acid involved in cellular osmoregulation in various species including man. This study was intended to compare the respective effects of cold storage and consecutive ischemic rewarming of the liver postischemic hepatic flow and hepatocellular outcome upon reperfusion with or without the addition of taurine to the preservation medium. Livers from male Wistar rats were rinsed free of blood via the portal vein and stored ischemically at 4 degrees C in UW solution. Livers from group 1 were then rinsed again with 10 ml Ringer's solution and reperfused with Krebs-Henseleit buffer at a constant pressure of 10 mmHg for 45 min at 37 degrees C in a nonrecirculating manner. Livers from groups 2 and 3 were subjected to 30 min of warm ischemia subsequent to cold storage and prior to reperfusion with 10 mM taurine added to the UW solution in group 3. While there were only very few signs of hepatic injury in group 1, the additional period of warm ischemia (group 2) led to a significant reduction in early perfusate flow and enhanced enzyme leakage from the livers during postischemic rinse and reperfusion. Livers in group 3 exhibited an amelioration in hepatic circulation and significantly reduced enzyme release as compared to group 2. The results clearly demonstrate a remarkable impact of postischemic rewarming on graft viability. Furthermore, the addition of taurine to the preservation medium was shown to improve hepatic circulation and enhance viability of the liver upon reperfusion.

Maintenance of viability and transport function after preservation of isolated rat hepatocytes in various simplified University of Wisconsin solutions

Rat hepatocytes were preserved for 24 hr with high recovery and good maintenance of viability and transport function both in University of Wisconsin (UW) solution and in various simplified UW solutions. Cell quality is somewhat affected after 48 hr of preservation in both the original UW solution and the simplified solutions. ATP content and uptake rate of taurocholic acid are more sensitive markers of cell viability than Trypan blue exclusion or the MTT test. A much less expensive solution than UW, containing only K(+)-lactobionate, KH2PO4, MgSO4 and raffinose, can be used successfully for preservation of rat hepatocytes for 24 hr for drug transport studies.

Microvascular changes of the liver preserved in UW solution. Pathological and immunohistochemical examination

Rat livers preserved in University of Wisconsin (UW) solution for 24 h were compared with those preserved in Euro-Collins (EC) solution before and after liver transplantation using an immunohistochemical method. Tissue ATP and total tissue adenine nucleotide (TAN) were measured using HPLC. The levels of TAN in the UW group or the EC group were significantly low compared with the control group (no preservation) after 24-h storage. In the EC group, the levels of tissue adenine nucleotides (TAN) decreased 1 h after reperfusion and never reached control levels. In the UW group, the levels of TAN increased a little 1 h after reperfusion and increased more 3 h after reperfusion. After 24-h preservation, the expression of factor VIII-related antigen (FRA) in endothelial cells of central veins was weak in the EC group; in the UW group, FRA was clearly detected in these cells. After reperfusion, although severe endothelial cell damage to the central veins and numerous FRA-positive substances were observed in EC group, endothelial cells of central veins retained their normal structure and FRA-positive substances were rarely noted in the UW group. In both groups, no endothelial changes were detected in portal veins. From these results, it is concluded that UW solution prevents endothelial cell damage and microcirculatory injury in zone III during the preservation period resulting in prevention of initial graft nonfunction. Also, measurement of the TAN level after reperfusion is useful to predict the function of the graft.

Phosphorus-31 nuclear magnetic resonance of isolated rat liver during hypothermic ischemia and subsequent normothermic perfusion

The effects of prolonged hypothermic ischemia and subsequent normothermic perfusion on the energetic metabolism and intracellular pH (pHin) of isolated rat livers were studied by phosphorus-31 nuclear magnetic resonance spectroscopy. Nucleoside triphosphate (NTP) depletion and intracellular pH were studied within an 18-h-storage phase, by using the following preservation media: Eurocollins (EC), UW Lactobionate (UW) and Bretschneider's solution (HTK). Values obtained after 8-h ischemia were chosen to estimate the performance of the various media: NTP levels were 37 +/- 7%, 10 +/- 5% and 0% of control levels, respectively, in livers stored in UW, HTK and EC solutions. pHin reached values of 7.15 +/- 0.10 in UW and HTK, and 6.96 +/- 0.10 in EC-stored livers. Ischemic damage was assessed by reperfusing the stored organ with Krebs medium: NTP recovery was around 70 +/- 20% for the three solutions used. Recovery of pHin was near the control value (7.23 +/- 0.08), except for EC solution (7.05 +/- 0.20). The main results are that (i) the rates of NTP and pHin decrease are strongly dependent on the nature of the preservation solution, whereas (ii) NTP recovery is not significantly different during post-ischemic reperfusion. With regard to animal survival, UW solution is at present considered largely superior to EC medium for liver preservation. Thus, our data suggest that the rates of NTP depletion and pHin fall during cold preservation could be both considered as better indicators assessing liver injury than the post-ischemic NTP recovery.

Warm Carolina rinse solution prevents graft failure from storage injury after orthotopic rat liver transplantation with arterialization

An injury to nonparenchymal cells, characterized by loss of viability of sinusoidal endothelial cells and activation of Kupffer cells, occurs after reperfusion of livers stored for transplantation. Recently, a new solution, Carolina rinse solution, was shown to prevent reperfusion injury to endothelial cells in vitro almost completely and to improve graft survival after orthotopic rat liver transplantation (ORLT) without arterialization. ORLT with arterialization permits longer cold storage of donor livers and more closely models human surgery. Therefore, we evaluated the effects of Carolina rinse solution on graft survival after ORLT with arterialization in syngeneic Lewis rats. Just prior to implantation, donor livers stored in University of Wisconsin (UW) solution were rinsed with 30 ml of Ringer's solution, saline, or Carolina rinse solution at 1 degree-4 degrees C. In livers stored for 15 h and rinsed with Ringer's or saline solution, long-term graft survival was only 8%. Using Carolina rinse solution containing 1 mmol and 200 mumol adenosine per liter, graft survival improved to 40% and 80%, respectively. Graft survival did not improve when using Carolina rinse solution with adenosine omitted or Ringer's solution containing 200 mumol adenosine per liter. Livers were also rinsed with Carolina rinse solution containing 200 mumol adenosine per liter at 28 degrees-30 degrees C rather than at 1 degree-4 degrees C. With warm Carolina rinse solution, survival improved further to 100%, 80%, and 50% after 15, 18, and 21 h of storage. After 18 h of storage, light and electron microscopy demonstrated marked denudation of the sinusoidal lining and activation of Kupffer cells in grafts rinsed with Ringer's solution.(ABSTRACT TRUNCATED AT 250 WORDS)

Beneficial effects of prewarming the donor liver for rat liver transplantation

Cold preservation of donor liver can injure the microcirculation enough to impair the function and survival of the transplanted liver. In this study, prewarming the donor liver to 10 degrees C to 12 degrees C after cold storage prior to implantation significantly increased survival rates in rats 1 week after surgery. Following 6, 8, or 9 hours of cold storage in chilled normal saline, prewarming increased survival rates from 40% to 78.6%, from 0% to 35.7%, and from 0% to 14.3%, respectively. The results suggest that pretreatment of the donor liver with warmth following cold storage and before implantation will improve the survival rate of liver transplanted rats.

Effect of sugars in the preservation solution on liver storage in rats

We have performed 128 rat liver transplants in order to examine the effect of sugars in preservation solutions on cold storage of rat livers. Glucose (Mw. 180), sucrose (Mw. 348), and raffinose (Mw. 594) were tested. Rat livers were preserved at 4 degrees C for 12, 16, 18, and 24 h in standard Eurocollins solution (EC solution) (solution A) or in one of three modified EC solutions in which 194 mM/liter glucose in standard EC solution was replaced by 140 mM/liter of glucose (solution B), sucrose (solution C), or raffinose (solution D). The osmolarity of the modified solutions (solution B-D) was 320 mOsm/liter. Using standard EC solution (solution A), the 1-week survival rate of rats receiving livers preserved for 12, 16, 18, or 24 h was 6/8, 4/8, 1/8, and 0/4, respectively. With solution B, in which 194 mM/liter glucose was replaced by 140 mM/liter glucose, 1 week survivors following transplantation of livers preserved for 12, 16, 18 or 24 h were 4/8, 3/8, 2/8 and 0/4, respectively. Solution C, which was identical to solution A except for the replacement of 194 mM/liter glucose by 140 mM/liter sucrose, gave the following 1-week survival rates: 5/8 for 12 h, 5/8 for 16 h, 2/8 for 18 h, and 0/4 for 24 hours preservation, respectively. Using solution D, which differed from A in the replacement of glucose by 140 mM/liter raffinose, the 1-week survival rates of rats grafted with livers preserved for 12, 16, 18, and 24 h were 6/8, 5/8, 3/8 and 0/4, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Review article: improved preservation of the liver for transplantation

This paper reviews the development of the techniques used for liver preservation and describes their clinical use. Recent advances with the introduction of lactobionate based solutions for simple cold storage are described and illustrated by their effect on the Cambridge/King's College Hospital transplant programmes. Better preservation of the liver has simplified the logistics of the transplant procedure, improving organ usage and allowing increased sharing of livers for urgent or paediatric cases.