A new dextran 40-based solution for liver preservation.

UW solution is at present the most efficient solution for preservation of livers for transplantation. We have developed an alternative solution based on dextran instead of hydroxyethyl starch and without raffinose, allopurinol, magnesium sulfate, insulin, penicillin, or dexamethasone, which all are used in UW solution. In addition, 62.5 mM potassium in UW solution is replaced with sodium. We tested this new solution for liver preservation using the isolated perfused rabbit liver. We found that livers preserved in the UW solution for 24 or 48 hr lost 11.6 +/- 2.6% and 16.8 +/- 2.0% of the prepreservation weight, respectively, as a sign of organ shrinkage (P less than 0.001). In contrast, no change in liver weight was observed after preservation in the new dextran-based solution. Similarly, no change in total tissue water of the rat liver slices was seen after preservation in the new solution. Furthermore, livers preserved for 24 hr in the UW solution or the new solution produced the same amount of bile as unpreserved livers. However, after preservation in the UW solution for 48 hr, bile production was reduced by 65% (P less than 0.05). In contrast, livers preserved for 48 hr in the new solution showed no reduction in bile production. We conclude that our new solution significantly improves long-term liver preservation, and with this modified solution, 48-hr preservation may be safe.     

Improvement of liver preservation quality with UW solution by chlorpromazine pretreatment of the donor in an experimental model

We investigated the effect of donor pretreatment with chlorpromazine (CPZ), in rabbit livers cold-stored in University of Wisconsin (UW) cold storage solution for 48 hr. Three groups of livers were investigated: livers flushed with Perfadex and immediately thereafter reperfused on an isolated circuit (controls), and livers cold stored in UW solution for 48 hr, with or without donor pretreatment with CPZ, 3 mg/kg. After preservation, reperfusion was performed in vitro, using an isolated circuit (IPL). The reperfusion medium consisted of an oxygenated Krebs-Henseleit bicarbonate solution supplemented with 5 mM glucose, 50 mg/L of streptomycin and penicillin G, and 3.5% Dextran 60 for oncotic support. Livers that were not pretreated with CPZ produced 5.3 +/- 1.2 ml bile/100 g (mean +/- SD) during 2 hr of IPL reperfusion. CPZ donor pretreatment significantly improved the bile flow to 17.1 +/- 6.9 ml (P less than 0.01, Wilcoxon). This figure was not different from that in control livers without a storage period (18.3 +/- 3.8 ml). Alanine aspartate aminotransferase (ASAT) released into the perfusate was measured, and levels were increasing during 2 hr of reperfusion. ASAT values were moderately increased in the preserved groups compared with controls (P less than 0.01), with no discernible differences between livers with and without CPZ pretreatment. It is concluded that CPZ pretreatment of the donor improves preservation quality, as evidenced by improved bile formation. The present results suggest that 48 hr cold storage in UW solution may be safe for clinical preservation, if donors are pretreated with chlorpromazine.     

Improved liver preservation for transplantation due to calcium channel blockade.

Intracellular calcium is an important determinant for cell death in organ hypothermic preservation for transplantation. In this study, we show that prevention of calcium entry improves the result of liver cold storage in UW solution. The isolated perfused rabbit liver was used. After 48 hr of cold storage in UW solution, bile production was reduced by 70% (P less than 0.005). However, by adding the calcium channel blockers verapamil or nifedipine (40 microM) to the UW solution, this reduction was abolished, and the livers produced the same amount of bile as unpreserved livers. Furthermore, addition of the calcium channel activator, BAY K8644 (40 microM), to the UW solution, reduced bile production by 50% (P less than 0.01) already after preservation for 24 hr. We conclude that calcium entry is of importance for liver function after preservation and cold storage, and that including a calcium channel blocker to the preservation solution makes long-term liver preservation safer.     

24-hour rabbit heart storage with UW solution. Effects of low-flow perfusion, colloid, and shelf storage

A new technique for 24-hr cardiac preservation is described utilizing very low flow perfusion (microperfusion) with a cold flush solution. Rabbit hearts were arrested with UW solution and then perfused with the same solution through the aortic root at 0 degrees C at a rate of 3-6 ml/gm heart weight/24 hr. When tested on an ex vivo working heart model, the cardiac output (CO) was 28.72 +/- 7.69 ml/g/min compared with fresh UW flushed controls of 26.48 +/- 2.25 ml/g/min. Both oxygenated highflow perfusion with a more conventional perfusate and 24-hr ice storage with UW led to inferior results. Omission of the colloid, hydroxyethyl starch (HES), from the UW solution or prolonged shelf storage were also significantly detrimental. When a previously untested colloid, polyethylene glycol 20,000, was substituted for HES for microperfusion, excellent cardiac function was obtained. In fact, the mean CO of this group, 31.91 +/- 5.70, was significantly above that of fresh HES-UW unstored controls. The suggestion that the UW solution might be improved by this substitution warrants further study.     

Comparison of solutions for preservation of the rabbit liver as tested by isolated perfusion

The University of Wisconsin (UW) solution consists of a relatively complex mixture of agents. In this study we compared simpler preservation solutions, namely, histidine-tryptophan-ketoglutarate glutarate (HTK) and phosphatebuffered sucrose (PBS) with different compositions of UW solution in the isolated perfused rabbit liver model. Livers were stored cold for 24 and 48 h. After 24 h of preservation, the amount of bile produced in UW-preserved livers was significantly greater (P<0.05) than that in HTK-preserved livers. Also, there was less LDH released into the perfusate in UW-preserved livers. There was more edema and lower K+/Na+ rations in HTK-preserved livers than in UW-preserved livers (all data P<0.05). After 48 h of preservation, the differences between livers preserved in UW or HTK solution were less noticeable than at 24 h and bile production was similar. LDH and AST release were greater in HTK-preserved livers than in UW livers, but these differences were not statistically significant. Preservation in PBS for 48 h was worse than in either UW or HTK solution. Substitution of polyethylene glycol (PEG) for hydroxyethyl starch (HES) in 48-h UW-preserved livers was not effective. We conclude that solutions simpler in composition than UW solution may be effective in kidney transplantation but do not appear suitable for successuful liver preservation.     

Verapamil improves rat hepatic preservation with UW solution

Verapamil, a calcium channel blocker, improves myocardial preservation during cold cardioplegia and protects against renal damage during periods of warm and cold ischemia. To determine if verapamil could prevent ischemic damage to livers during and after cold storage, harvested rat livers were flushed with either University of Wisconsin (UW) solution or UW solution with 25 mg/liter verapamil. Twenty rats were used in each group. After 24 hr of storage at 4 degrees C, livers were perfused with oxygenated blood through the portal veins for 2 hr at 37 degrees C and pH 7.4. Liver enzymes, electrolytes, and perfusate flow rate were determined at 30-min intervals. At 90 min of perfusion, the verapamil group of livers had less elevation of AST (110 +/- 17 IU/liter vs 172 +/- 25 IU/liter, P less than 0.05), ALT (115 +/- 21 IU/liter vs 210 +/- 34 IU/liter, P less than 0.05), and LDH (962 +/- 170 IU/liter vs 1452 +/- 253 IU/liter, NS). Verapamil livers produced more bile than controls (6.9 +/- 1.9 microliters/g vs 2.3 +/- 1.7 microliter/g, P less than 0.05) and maintained a higher portal flow rate throughout the perfusion. Both groups showed similar reduction in liver weights after storage (3.9 +/- 0.9% vs 2.8 +/- 0.7%) and required the same amount of bicarbonate for correction of acidosis during perfusion (2.6 +/- 0.2 mM vs 2.8 +/- 0.2 mM). Light microscopic exam after perfusion showed hepatocyte damage in 30% of control livers, but 0% of verapamil livers. We conclude that verapamil-treated rat livers showed less damage and better function upon reperfusion after 24 hr of cold storage. This agent may be clinically useful as an additive to the UW preservation solution for livers.     

The effects of fasting on the quality of liver preservation by simple cold storage

Although livers can be successfully preserved for 24 hr or more, often the transplanted livers have poor or no (primary nonfunction) function. The quality of the liver does not appear dependent upon the time of preservation but may be dependent upon the condition of the donor. In this study we have investigated the effects of fasting on the quality of livers for transplantation. Rabbits were fasted (48 hr) and livers preserved in the UW solution for 6-8 hr. Functions of the liver were analyzed by isolated perfusion for 2 hr. Also, pigs were fasted for 72 hr, livers preserved for 12 hr, and viability determined by orthotopic transplantation. Fasting depleted the liver glycogen by 85% but had no effect on ATP or glutathione concentrations. Rabbit livers from fasted animals produced similar amounts of bile, released similar concentrations of lactate dehydrogenase (LDH) and aspartate amino transaminase (AST) into the perfusate, maintained similar concentrations of ATP and glutathione in the tissue, and had a similar intracellular K:Na ratio after 24-hr preservation when compared to livers from fed animals. After 48-hr preservation, livers from fasted animals were less viable than livers from fed animals, including: reduced bile production (2.0 +/- 0.3 vs. 5.0 +/- 0.9 ml/2 hr, 100 g), greater release of LDH (3701 +/- 562 units vs. 1123 +/- 98 units) and AST, less ATP (0.326 +/- 74 vs. 0.802 +/- 160 nmol/g), less glutathione (0.303 +/- 13 vs. 0.933 +/- 137 nmol/g), and a lower K:Na ratio (1.5 +/- 0.9 vs. 7.4 +/- 0.6). Pigs receiving livers from fed animals preserved for 12 hr had better survival (5/6, 83%) than livers from fasted animals (3/6, 50%). The results show that the nutritional status of the donor can affect the outcome of liver preservation and transplantation. Increased injury in livers from fasted animals may be due to the loss of glycogen that may be an essential source of energy in the initial posttransplant period. In clinical liver transplantation the nutritional status of the donor may be an important factor in the initial function of the liver, and methods to increase the nutritional status of the donor may be important in increasing the quality of livers.     

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

Preservation of rat livers by simple ice-storage has been demonstrated after 24 hr using the University of Wisconsin (UW) solution. Equally good preservation could be obtained by substituting hydroxyethyl starch (HES) from another source or by omission of HES from the UW formulation. Survival, early and late function, and morphology at the end of a 3-month follow-up period were essentially similar for all three test groups. It is concluded that HES is not required for optimum preservation of the rat liver in this treatment model.     

A comparison of Collins and UW solutions for cold ischemic preservation of the rat liver

A new solution which can extend successful preservation times for hepatic allografts was recently developed at the University of Wisconsin (UW). To examine the mechanism of improved viability using this solution, we developed a model of orthotopic hepatic transplantation in the rat. As a baseline study, we compared parameters of viability of allografts preserved in Collins solution to those preserved in UW, including survival, bile output, peak AST, and allograft weight change during storage. Seventy-four rats were transplanted following storage in Collins solution and 70 rats were transplanted after storage in UW. Cold-storage time varied between 2 and 24 hr. The survival with preservation in UW was significantly better than that with Collins when storage time was greater than 2 hr. The preservation time for a viable organ using UW was greater than double that using Collins. The peak AST using UW was lower than that with Collins for cold ischemic times (CIT) up to 10 hr, with significance demonstrated at 5-6 and 7-8 hr when compared with Collins. Prolonged CIT resulted in an increase in liver weight with Collins-preserved livers and a decrease in weight with UW-preserved livers. Using a model of orthotopic liver transplantation in the rat, we demonstrated a doubling of preservation time when UW solution was substituted for Collins. Similar improvements in recipient survival and biochemical parameters of injury have been demonstrated in the canine model and in human clinical trials.     

Hemodynamic and biochemical changes during normothermic and hypothermic sanguinous perfusion of the porcine hepatic graft

Using an ex vivo liver sanguinous perfusion system, hemodynamic and biochemical changes of the porcine livers were studied, which were preserved cold (4 degrees C) for 24 hr in University of Wisconsin solution and reperfused with normothermic (37 degrees C) (n = 8) or hypothermic (32 degrees C) (n = 8) blood for 3 hr. Six more livers were reperfused with normothermic blood (37 degrees C) immediately after procurement as controls. The total hepatic blood flow was adjusted to 1 ml/min/g liver weight, in which hepatic artery and portal vein flows were administered at a 1:2 ratio. In livers stored cold for 24 hr in UW solution and perfused normothermically, a statistically higher hepatic artery resistance was exhibited at 30 and 60 min after reperfusion (P less than 0.05), and there was lower bile output (P less than 0.05) at 90 and 120 min as compared to the controls. In livers stored cold for 24 hr in UW solution and perfused hypothermically, as compared to ones perfused normothermically, statistically higher hepatic-artery and portal-vein resistances (P less than 0.05) were observed throughout the perfusion period and 60 min after reperfusion, respectively. In addition, bile output and oxygen consumption of these livers were statistically lower than those of ones perfused normothermically (P less than 0.05). In contrast, chemistries of the perfusate of livers perfused hypothermically were comparable to ones perfused normothermically. Histologic examination of the liver perfused hypothermically demonstrated hepatic arterial and/or portal venous congestion and mild-to-moderate hemorrhage in the portal triads. This study suggests that livers preserved for a prolonged period of time demonstrate a high hepatic arterial resistance shortly after revascularization, and that recipient hypothermia after revascularization may be a risk factor for the development of hepatic arterial thrombosis following liver transplantation.     

Hypothermic machine perfusion of rat livers preserves endothelial cell function

This study was conducted to investigate the effect of starch in the preservation solution during hypothermic machine perfusion (HMP) on endothelial cell and hepatocyte functions in an isolated perfused rat liver model. Livers isolated from male Sprague-Dawley rats were perfused with the University of Wisconsin (UW) solution (HMP + starch group); modified UW solution (starch omitted) (HMP - starch group) at 0.4 mL/min per g liver; or simply stored in the UW solution (SCS group) at 4 degrees C for 24 hours. Following preservation, livers from HMP + starch, HMP - starch, SCS, and control group (without preservation) were perfused with Krebs-Henseleit Buffer solution at 37 degrees C for 30 minutes. Samples were taken every 10 minutes during 30-minute warm perfusion to assess hepatocyte and endothelial cell function and damage. After 24 hours of hypothermic preservation and 30 minutes rewarming, livers in the HMP + starch group displayed significantly lower lactate dehydrogenase levels and higher bile production. Endothelial cell function was also improved as indicated by hyaluronic acid uptake and shorter transient time for albumin observed in a multiple indicator dilution study. Liver wet and dry ratio and histological findings confirmed reduced edema formation in the tissue of the HMP + starch group livers compared with that of the HMP - starch and SCS group livers. These results suggest that HMP with the UW solution containing starch improve endothelial cell function and induce less hepatocellular damage following 24-hour preservation compared to SCS and HMP with the starch-free UW solution. These results also suggest that oncotic support may be an important component in preserving hepatic microcirculation in HMP.     

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.     

Calcium antagonists in sodium lactobionate sucrose solution for rat liver preservation.

The effects of the calcium antagonists, chlorpromazine (CPZ), nisoldipine (NIS), trifluoperazine (TFP), and nicardipine (NIC) were compared in rat livers following either 20- or 30-hr ice storage in sodium lactobionate sucrose solution (SLS). Survivals beyond 7 days after orthotopic liver transplantation following 20-hr cold storage were 1/14 in the University of Wisconsin solution, 4/14 in SLS, 4/8 in UW+CPZ, 7/8 in SLS+CPZ. Survivals beyond 7 days after OLT following 30-hr cold storage were 3/8 in SLS+CPZ, 3/8 in SLS+NIS, 2/8 in SLS+TFP, 0/8 in SLS+NIC, and 0/8 in SLS alone. Survival rates were significantly (P less than 0.05) better in both SLS+CPZ and SLS+NIS than in UW and SLS alone. The effluent lactate dehydrogenase (LDH) levels and pH changes were measured at the time of OLT. After 20 hr, LDH levels were 525 +/- 78 IU/L (mean +/- SEM) in UW, 492 +/- 44 in SLS, 322 +/- 35 in UW+CPZ, and 290 +/- 39 in SLS+CPZ. After 30 hr, LDH values were 416 +/- 40 in SLS+CPZ, 450 +/- 25 in SLS+NIS, 448 +/- 21 in SLS+TFP, 573 +/- 18 in SLS+NIC, and 614 +/- 68 in SLS. The LDH levels for SLS+CPZ and SLS+NIS were significantly lower than those of SLS and UW (P less than 0.01). The pH changes in the effluent were significantly less in both the CPZ and NIS groups (P less than 0.01). This study demonstrated improved liver preservation by the use of a simplified colloid-free lactobionate solution containing sodium as the principal cation. The addition of CPZ or NIS to the solution demonstrated the same potency for significant improvement in efficacy of this solution, while NIC was ineffective.     

Advantages of normothermic perfusion over cold storage in liver preservation

BACKGROUND: To minimize the ischemia-reperfusion injury that occurs to the liver with the current method of preservation and transplantation, we have used an extracorporeal circuit to preserve the liver with normothermic, oxygenated, sanguineous perfusion. In this study, we directly compared preservation by the standard method of simple cold storage in University of Wisconsin (UW) solution with preservation by perfusion. METHODS: Porcine livers were harvested from large white sows weighing between 30 and 50 kg by the standard procedure for human retrieval. The livers were preserved for 24 hr by either cold storage in UW solution (n=5) or by perfusion with oxygenated autologous blood at body temperature (n=5). The extracorporeal circuit used included a centrifugal pump, heat exchanger, and oxygenator. Both groups were then tested on the circuit for a 24 hr reperfusion phase, analyzing synthetic function, metabolic capacity, hemodynamics, markers of hepatocyte and reperfusion injury, and histology. RESULTS: Livers preserved with normothermic perfusion were significantly superior (P=0.05) to cold-stored livers in terms of bile production, factor V production, glucose metabolism, and galactose clearance. Cold-stored livers showed significantly higher levels of hepatocellular enzymes in the perfusate and were found to have significantly more damage by a blinded histological scoring system. CONCLUSIONS: Normothermic sanguineous oxygenated perfusion is a superior method of preservation compared with simple cold storage in UW solution. In addition, perfusion allows the possibility to assess viability of the graft before transplantation.     

Twenty-four-hour canine lung preservation using UW solution

The left lungs of 14 mongrel dogs were isolated, preserved, and then reperfused for 120 min. Three groups of lungs were investigated: group 1, nonpreserved lungs (control n = 5); group 2, lungs were flushed with UW solution and cold-stored (4-6 degrees C) in the same flush solution for 24 hr (n = 4); and group 3, lungs flushed and cold-stored with modified Euro-Collins' solution for 24 hr (n = 5). Airway pressure (AWP), static lung compliance (Cst), and pulmonary vascular resistance (PVR) 120 min after reperfusion were significantly higher in group 3 compared with the lungs in group 1 and group 2. AWP was 18.7 +/- 3.9 in group 1, 21.1 +/- 3.8 in group 2, and 33.8 +/- 9.2 ml/cmH2O (mean +/- SD) in group 3 (P less than 0.05). Cst was 14.0 +/- 3.5, 10.8 +/- 1.5, and 6.2 +/- 1.2 ml/cmH2O, respectively (P less than 0.01). Pulmonary vascular resistance was 125 +/- 16, 120 +/- 42, and 410 +/- 108 mmHg/L/min (P less than 0.05). We conclude that UW solution is useful for hypothermic canine lung preservation.     

Protective effects of trifluoperazine on the microcirculation of cold-stored livers

Previous studies have shown a protective effect of trifluoperazine (TFP), a calmodulin inhibitor, upon the microcirculation of cold-stored kidneys. The present study points to similar beneficial effects of TFP on the microcirculation of cold-stored livers; 25 canine livers were preserved for 24 hr with Euro-Collins' solution (EC) (n = 8), University of Wisconsin solution (UW) (n = 7), or UW + TFP (n = 10). The stored livers underwent heterotopic transplantation (HLTX); hepatic-artery and portal-vein pressure and flow were monitored; oxygen consumption and extraction were measured before HLTX and at 15-min intervals after reperfusion, for 1 hr. Mean hepatic-artery and portal-vein flow (HAF & PVF) prior to donor hepatectomy were 172 and 530 cc/min, respectively. Poor HAF and PVF occurred in EC-HLTX (mean 35, 175 cc/min, respectively). The damaged EC-flushed livers could not compensate to the decreased hepatic blood flow by increased oxygen extraction (oxygen consumption and extraction, 8.7 vol.% and 48%, respectively). Light and electron microscopy showed severe liver necrosis and periportal hemorrhages. Improved hepatic-artery and portal-vein flows were seen in UW HLTX (105 and 254 cc/min), and oxygen consumption and extraction were 16.4 vol.% and 66%, respectively. Liver biopsy taken just before reperfusion revealed well-preserved liver architecture. Liver biopsy obtained 1 hr after reperfusion revealed marked edema of the portal triad, sinusoid congestion, and hemorrhage. Electron-microscopy biopsies obtained during reperfusion at 15-min intervals revealed severe vasospasm of the terminal hepatic arterioles and progressive damage to the liver microcirculation. The addition of TFP to the UW-flush solution resulted in excellent protection of the liver microcirculation. Marked increase in hepatic-artery and portal-vein blood flow was noted after reperfusion (mean 167 and 421 cc/min, respectively (P 0.02 vs. UW: P 0.001 vs. EC). The recovery of metabolic activity was evident by the high oxygen consumption and extraction (25.8 vol.% and 80%, respectively). And serial liver biopsies obtained after reperfusion have shown excellent protection of liver architecture and the absence of hepatic arteriolar vasospasm. Taken together, these data suggest that the addition of TFP to the UW solution protects the liver microcirculation by rendering the hepatic microcirculation insensitive to vasospastic stimuli during reperfusion, thus permitting better metabolic recovery after transplantation.     

24-hour rat liver preservation using UW solution and some simplified variants

The results of a series of 32 rat liver transplants are described to analyze the efficacy of components of UW solution. Rat livers were stored at 4 degrees C in standard UW solution or one of three simplified variants for 24 hr prior to orthotopic liver transplantation. In standard UW solution (solution A) the one-week survival rate was 3 of 8. Using solution B, which differs from solution A in the omission of hydroxyethyl starch and adenosine, the one-week survival rate was 2 of 8. Solution C, a further-simplified version of solution B with omission of allopurinol, Bactrim, and insulin, gave a one-week survival rate of 3 of 8. Solution D is identical to solution B except that the sodium and potassium concentrations are reversed. Using this solution, 5 of 8 rats survived more than one week. We conclude that the effectiveness of UW solution is maintained in a substantially simplified form, and that solution D, with the Na/K ratio reversed to give a high Na variant, may improve survival.     

A comparison of a new solution combining histidine and lactobionate with UW solution and eurocollins for rat liver preservation

Forty-six rat liver transplants were performed to investigate the effectiveness of a simplified lactobionate solution containing histidine as a buffer (histidine-lactobionate solution) and to compare it with University of Wisconsin solution. This new solution is isoosmotic (320 mOsm/L) and has a higher sodium content and a lower potassium content (Na: 90 mEq/L, K: 45 mEq/L) than standard UW solution. Buffering capacity is increased by adding histidine (90 mM/L) together with KH2PO4 (20 mM/L) and is greater than that of Eurocollins solution or UW solution. Adenosine, insulin, hydroxyethyl starch, and dexamethasone that are included in UW solution are not included in the new solution. The 1-week survival rate of rats transplanted with livers preserved in this solutions at 4 degrees C was 85% (11/13) following 24-hr preservation and 33% (2/6) after 30-hr preservation. By contrast, UW solution gave only a 29% (5/17) survival rate after 24-hr preservation and 0% (0/6) survival after 30-hr preservation, demonstrating that this simplified UW solution with histidine is superior to UW solution in rat liver preservation. No rats (0/4) receiving livers preserved for 24 hr in Eurocollins solution survived. These findings show that the inclusion of histidine as a buffer dramatically improves the effectiveness of lactobionate-based preservation solutions and justify application in a large-animal model and subsequently in clinical liver transplantation.     

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.     

Preservation of the canine liver for 24-48 hours using simple cold storage with UW solution

The results of a series of 29 orthotopic liver transplants in the dog are described. The livers were preserved in a new cold storage fluid, UW solution, and were successfully transplanted after periods of storage of 24, 30, 36, and 48 hr. All six animals transplanted after 24 hr survived beyond 5 days after transplantation and had excellent graft function. Four of six survived for at least 5 days after 30 hr of cold storage, and five of five after 36 hr. Five of six consecutive dogs that received transplants that had been cold-stored for 48 hr survived for 5 or more days. This solution represents a substantial advance over all existing cold storage solutions for liver preservation.