Machine perfusion preservation of the non-heart-beating donor rat livers using polysol, a new preservation solution

AIMS: The increasing shortage of donor organs has led to a focus on extended criteria donors, including the non-heart-beating donor (NHBD). An optimal preservation method is required to facilitate successful transplantation of these ischemically damaged organs. The recent literature has shown clear advantages of hypothermic machine perfusion (MP) over cold storage (CS). For MP, modified University of Wisconsin perfusion solution (UW-G) is often used, which, however, is known to cause microcirculatory obstruction, is difficult to obtain, and is expensive. Therefore, Polysol was developed as a MP preservation solution that contains specific nutrients for the liver, such as amino acids, energy substrates, and vitamins. The aim of this study was to compare Polysol with UW-G in a NHBD rat liver model. METHODS: After 24 hours hypothermic MP of NHBD rat livers using UW-G or Polysol, liver damage and function parameters were assessed during 60 minutes of reperfusion with Krebs-Henseleit buffer. Control livers were reperfused after 24 hours CS in UW. RESULTS: Liver enzyme release was significantly higher among the CS-UW group compared to MP using UW-G or Polysol. Flow during reperfusion was significantly higher when using Polysol compared to UW-G. Bile production and ammonia clearance were highest when using Polysol compared to UW-G. There was less cellular edema after preservation with Polysol compared to UW-G. CONCLUSIONS: MP of NHBD rat livers for 24 hours using UW-G or Polysol resulted in less hepatocellular damage than CS in UW. MP of NHBD livers for 24 hours using Polysol is superior to MP using UW-G.     

Improved machine perfusion preservation of the non-heart-beating donor rat liver using Polysol: a new machine perfusion preservation solution.

Waiting lists for transplantation have stimulated interest in the use of non-heart-beating donor (NHBD) organs. Recent studies on organ preservation have shown advantages of machine perfusion (MP) over cold storage (CS). To supply the liver with specific nutrients during MP, the preservation solution Polysol was developed. The aim of our study was to compare CS in University of Wisconsin solution (UW) with MP using UW-gluconate (UW-G) or Polysol in an NHBD model. After 30 minutes of warm ischemia, livers were harvested from rats for preservation by either CS, MP-UW-G, or MP-Polysol. After 24 hours of preservation, livers were reperfused with Krebs-Henseleit buffer (KHB). Perfusate samples were analyzed for liver damage and function. Biopsies were examined by hematoxylin and eosin staining and transmission electron microscopy. Liver damage was highest after CS compared with the MP groups. MP using Polysol compared with UW-G resulted in less aspartate aminotransferase (AST) and alanine aminotransferase (ALT) release. Perfusate flow, bile production, and ammonia clearance were highest after MP-Polysol compared with CS and MP-UW-G. Tissue edema was least after MP-Polysol compared with CS and MP-UW-G. In conclusion, preservation of the NHBD rat liver by hypothermic MP is superior to CS. Furthermore, MP using Polysol results in better-quality liver preservation compared with using UW-G.     

Machine perfusion preservation of the pig liver using a new preservation solution, polysol

INTRODUCTION: The current gold standard for donor liver preservation is cold storage in a preservation solution (4 degrees C), such as Celsior or the University of Wisconsin solution (UW). Recent studies have suggested the benefits of machine perfusion (MP) over cold storage. To improve the results of MP, an enriched preservation solution (named Polysol) was developed, which in a rat liver preservation model proved to be superior to the UW-gluconate solution. The aim of this study was to assess Polysol in a pig liver preservation model. MATERIALS AND METHODS: Female pigs (35 to 40 kg) were used as liver donors. After heparinization, the liver was washed out using Ringer's lactate, followed by the preservation solution (4 degrees C). The liver was preserved for 24 hours by either cold storage using Celsior (n=5) or MP using Polysol (n=5). For analysis of liver damage and function, livers were reperfused for 60 minutes using oxygenated Krebs-Henseleit buffer. RESULTS: CS-Celsior caused significantly more damage compared with MP-Polysol (t=60, AST: 622+/-215 versus 222+/-55; ALT: 17+/-6 versus 5+/-1). Intravascular resistance during reperfusion was significantly higher after CS-Celsior compared with MP-Polysol (t=0, 0.20+/-0.01 and 0.11+/-0.02 mm Hg/mL/min, respectively). No differences were seen regarding ammonia clearance and urea production. In both groups, no bile was produced during reperfusion. CONCLUSIONS: In an ex vivo pig liver preservation model significantly less damage was observed after machine perfusion preservation using Polysol, in comparison to cold storage using Celsior.     

Optimization of a new preservation solution for machine perfusion of the liver: which is the preferred colloid?

AIMS: Machine perfusion (MP) has proven to be beneficial in experimental preservation of the liver. The modified University of Wisconsin solution (UW-Gluconate or UW-G) is used as the MP preservation solution of choice. We have developed Polysol, an enriched MP preservation solution based on a colloid. We sought to optimize Polysol by substituting the colloid hydroxyethylstarch (HES) with the colloids dextran and polyethylene glycol (PEG). METHODS: In an isolated perfused rat liver model, hepatocellular damage and liver function were assessed during reperfusion with Krebs-Henseleit buffer after 24 hours hypothermic MP using Polysol-HES, Polysol-dextran, or Polysol-PEG. Control livers were preserved by MP using UW-G. RESULTS: Compared to MP-UW-G, MP using Polysol resulted in significantly less damage and improved function during reperfusion. MP using Polysol-dextran or Polysol-PEG resulted in equal or less damage than Polysol-HES. Differences in ammonia clearance and bile production were not significant. Tissue edema was higher after MP using Polysol-HES as compared to Polysol-dextran and Polysol-PEG. CONCLUSIONS: MP of rat livers for 24 hours using UW-G results in more extensive damage and reduced liver function compared to MP using Polysol. MP using Polysol-dextran or Polysol-PEG results in equal or even better preservation compared to Polysol-HES.     

Subnormothermic machine perfusion protects against rat liver preservation injury: a comparative evaluation with conventional cold storage

Hypothermic machine perfusion (MP) of the liver has been reported to improve graft function reclaiming marginal livers, such as those from non-heart-beating donors. Livers from obese donors often have fatty infiltrates and are more susceptible to hypothermic conditions. No data exist about MP at temperatures >4 degrees C. This study evaluated liver function after organ preservation by comparing MP at 20 degrees C with conventional cold storage. METHODS: For MP, rat livers were perfused for 6 hours using an oxygenated Krebs-Henseleit (KH) solution at 20 degrees C (pH 7.4). For cold storage, livers were perfused in situ and preserved with Celsior solution at 4 degrees C for 6 hours. The reperfusion period with KH (2 hours at 37 degrees C) was performed under the same conditions both among livers preserved by MP or cold storage. Hepatic enzyme release (aspartate aminotransferase [AST], alanine aminotransferase [ALT], lactate dehydrogenase [LDH], and gamma-glutamyl transferase [GGT]), bile production, and ATP levels were measured during MP and reperfusion. RESULTS: At the end of reperfusion, livers preserved by MP showed significantly decreased liver damage compared with cold storage: AST, 18 +/- 4 vs. 45 +/- 6 mU/mL (P < .01); ALT, 1.5 +/- .07 vs. 6 +/- 0.5 mU/mL (P < .01); and LDH, 82 +/- 2 vs. 135 +/- 29 mU/mL (P < .05). No difference was observed between bile production between MP and cold storage. High levels of biliary GGT and LDH were found in cold preserved livers. ATP levels were higher in livers preserved with MP compared with those preserved by cold storage. CONCLUSIONS: MP at 20 degrees C resulted in a better quality of liver preservation, improving hepatocyte survival, compared with conventional cold storage. This may provide a new method for successful utilization of marginal livers, in particular fatty livers.     

Preservation of steatotic livers: a comparison between cold storage and machine perfusion preservation.

Liver grafts are frequently discarded due to steatosis. Steatotic livers can be classified as suboptimal and deteriorate rapidly during hypothermic static preservation, often resulting in graft nonfunction. Hypothermic machine perfusion (MP) has been introduced for preservation of donor livers instead of cold storage (CS), resulting in superior preservation outcomes. The aim of this study was to compare CS and MP for preservation of the steatotic donor rat liver. Liver steatosis was induced in male Wistar rats by a choline-methionine-deficient diet. After 24 hours hypothermic CS using the University of Wisconsin solution (UW) or MP using UW-Gluconate (UW-G), liver damage (liver enzymes, perfusate flow, and hyaluronic acid clearance) and liver function (bile production, ammonia clearance, urea production, oxygen consumption, adenosine triphosphate [ATP] levels) were assessed in an isolated perfused rat liver model. Furthermore, liver biopsies were visualized by hematoxylin and eosin staining. Animals developed 30 to 60% steatosis. Livers preserved by CS sustained significantly more damage as compared to MP. Bile production, ammonia clearance, urea production, oxygen consumption, and ATP levels were significantly higher after MP as compared to CS. These results were confirmed by histology. In conclusion, MP improves preservation results of the steatotic rat liver, as compared to CS.     

Electrical impedance of the liver during experimental long-term liver preservation

Measurements of electrical impedance were performed to assess ischemic damage in the rabbit liver during long-term preservation with University of Wisconsin (UW) or histidine-tryptophan-ketoglutarate (HTK) solution. The impedance was measured at a frequency of 200 Hz after in situ perfusion and after cold storage for 24 and 48 hours in UW or HTK solution (six livers per group). Z(200 Hz) was significantly higher (P < .01) after 48 compared with 24 hours of cold storage with both protection solutions without significant differences between the livers preserved with both solutions. Electrical impedance was observed to be a sensitive indicator of liver damage during long-term protection, showing similar preservation quality for both preservation solutions.     

Seventy-two-hour preservation of the canine liver by machine perfusion

The UW solution effectively preserves the dog liver for up to 48 hr by simple cold storage. This solution contains lactobionate as the primary impermeant. Another solution developed for machine perfusion of the kidney is similar to the UW solution but contains gluconate in place of lactobionate. In this study the UW gluconate solution was used for the continuous hypothermic machine perfusion of dog livers for 72 hr. Dog livers were continuously perfused at 5 degrees C through the portal vein at a pressure of 16-18 mm Hg and transplanted. Seven of 8 dogs survived for 7 or more days following orthotopic transplantation. The livers functioned as well as those preserved for 48 hr by cold storage in the UW solution as indicated by various liver-function tests. Successful machine perfusion was only achieved when the perfusate contained a high concentration of potassium (125 mM) but not with a high concentration of sodium (125 mM). This study demonstrates the feasibility of machine-perfusion preservation of the liver that yields longer preservation of equal quality compared to simple cold storage. For the development of truly long-term preservation (5 or more days) and better quality short-term preservation, machine perfusion may be the method of choice.     

Survival transplantation of preserved non-heart-beating donor rat livers: preservation by hypothermic machine perfusion

BACKGROUND: Non-heart-beating donor (NHBD) livers are an untapped source with the potential to provide relief to the current donor shortage problem. Hypothermic machine perfusion (MP) has the potential to reclaim and preserve these marginal donor organs. METHODS: This study compared 5-day survival in a rat NHBD liver transplantation model with simple cold storage (SCS) and MP-preserved tissues that had experienced 30 min of warm ischemia followed by a 5-hr preservation period with the University of Wisconsin solution. Total release of lactate dehydrogenase (LDH) and alanine aminotransferase (ALT) were determined at major time points. Bilirubin levels and histology were examined after 5-day survival. RESULTS: Six of seven control livers and five of six MP livers survived, whereas SCS tissues had survival in zero of seven. The results showed that MP livers had reduced release of LDH and ALT after 5 hr of storage, 5.07+/-1.42 and 2.02+/-0.69 U (mean+/-SE), respectively, compared with SCS, 15.54+/-0.81 and 3.41.3+/-0.73 U, respectively. Bilirubin values after 5-day survival of MP livers (1.17+/-0.49 mg/dL) were comparable to controls (0.91+/-0.36 mg/dL). Histology confirms that SCS displayed increased necrosis and MP tissue showed regions of near normal hepatic structure. CONCLUSIONS: These results suggest that MP for 5 hr improves survival and reduces cellular damage of liver tissue that has experienced 30 min of warm ischemia when compared with SCS tissues. Further studies need to be conducted, but this study suggests that MP preservation has the potential to reclaim and preserve NHBD liver tissues.     

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.     

A new transportable machine for the preservation of livers to be transplanted by means of hyperbaric oxygenation perfusion

The preservation of livers to be transplanted is currently obtained by static cold storage at 4 C degrees and flushing with UW solution. New methods of preservation are being studied that take advantage of machines for continuous hypothermic perfusion of the organ. Such machines have permitted a lengthening of preservation times and the use of livers from non-beating-heart donors. In an attempt to eliminate the damage due to hypothermia, to lengthen preservation times, and to extend the availability of livers to be transplanted, also using those subjected to short periods of warm ischaemia, we have constructed a transportable machine that produces a hyperbaric atmosphere and allows continuous perfusion of the liver. Ten pig livers from beating-heart donors were perfused with Ringer solution in hyperbaric conditions with oxygen at temperatures ranging from 10 to 25 degrees C for periods of up to 24 hours and studied by means of histopathological analysis and tests of mitochondrial activity (FAU) in order to verify cell viability. The group of livers perfused up to 15 hours yielded an FAU value of 169.40 +/- 5.5 compared to the value of the non-perfused livers (controls) established as 100 and those perfused up to 24 hours had a FAU value of 139.18 +/- 10.7 compared to the controls established as 100, thus demonstrating cell viability. The viability of the organs after preservation with our procedure in the hyperbaric oxygenation perfusion machine gives us good reason to believe that, after appropriate further confirmation of the results, it will be possible to use the machine for the transplantation both of livers subjected to warm ischaemia and of livers preserved for longer periods than is currently the case.     

Euro-Collins solution versus UW-solution for long-term liver preservation in the isolated rat-liver perfusion model.

To compare UW-solution (UW) and Euro-Collins (EC) for long-term liver preservation we investigated the morphology and metabolic capacity of rat liver after 18 and 42-hours cold-storage in either UW or EC. After harvesting the rat liver was transferred to a perfusion chamber where it was perfused for 10 min with UW or EC at 4 degrees C. Thereafter livers were stored at 4 degrees C in UW or EC for 18 hours (both groups n = 6) or for 42 hours (both groups n = 8). After 18-hr or 42-hr cold-storage a 2-hr warm perfusion (37 degrees C) was started with Krebs-Ringer solution with carbogen to which 125Iodine-triiodothyronine (T3) was added. Control livers (n = 8) were immediately perfused with Krebs-Ringer without cold-storage. The following parameters were assessed: ASAT-levels in the perfusate, T3-metabolites in the bile and the perfusate, the perfusion pressure, the volume of bile secreted and light-microscopical morphology at the end of the warm perfusion period. After cold storage in UW-solution the ASAT-levels in the perfusate were lower than after storage in EC as well as the perfusion pressures. These livers demonstrated a better T3-metabolism and secreted more bile than EC-stored livers. Histological examination showed more tissue damage in the EC-stored livers than in the UW stored livers. We conclude that cold-storage of rat liver in UW-solution resulted in a better morphology and metabolic capacity as compared with EC-solution.     

Functional recovery of donation after cardiac death liver graft by continuous machine perfusion preservation in pigs

Introduction

Grafts from donation after cardiac death (DCD) will greatly contribute to the expand the donor pool. However, these grafts may require the development of the preservation methods because of primary nonfunction and severe ischemic bile duct injury.

Methods

Porcine livers were perfused with a newly developed machine perfusion (MP) system. Each system for the portal vein or the hepatic artery had a roller pump, a flow meter, and a pressure sensor. The livers were perfused with University of Wisconsin (UW)-gluconate at 4°C-6°C for 3 hours after 2 hours simple cold storage (CS). The portal vein flow rate was 0.5 mL/min/g liver (pressure, 10 mm Hg) and the hepatic artery flow rate was 0.2 mL/min/g liver (pressure, 30 mm Hg). Orthotopic liver transplantation was performed in pigs comparing Group 1 (n = 4) procured after acute hemorrhagic shock preserved by MP, Group 2 (n = 3) procured after warm ischemia time (WIT) of 30 minutes with CS preservation, and Group 3 (n = 4) procured with 30 minutes of WIT and MP preservation.

Results

Collected effluent aspartate aminotransferase (AST) and lactate dehydrogenase (LDH) levels in the perfusion solution and serum AST and LDH were significantly lower in Group 1. AST and LDH results were lower in Group 3 than Group 2. Survival rates in Groups 1 and 3 were 3/4, but 0/3 in Group 2.

Conclusion

MP preservation was a useful promising preservation mode for DCD liver grafts.     

Sequential cold storage and normothermic perfusion of the ischemic rat liver

Extending transplant criteria to include livers obtained from donors after cardiac death (DCD) could increase the liver donor pool, but conventional simple cold storage of these ischemic organs can lead to poor graft function after transplantation. Experimental normothermic machine perfusion has previously proven to be useful for the recovery and preservation of DCD livers, but it is more complicated than conventional cold storage, and, therefore, is perhaps not practical during the entire preservation period. In clinical situations, the combined use of simple cold storage and normothermic perfusion preservation of DCD livers might be more realistic, but even a brief period of cold storage prior to normothermic preservation has been suggested to have a negative impact on graft viability. In this study we show that rat livers subjected to 45 minutes of ex vivo warm ischemia followed by 2 hours of simple cold storage can be reclaimed by 4 hours of normothermic machine perfusion. These livers could be orthotopically transplanted into syngeneic recipients with 100% survival after 4 weeks (N = 10), similar to the survival of animals that received fresh livers that were stored on ice in University of Wisconsin (UW) solution for 6 hours (N = 6). On the other hand, rats that received ischemic livers preserved on ice in UW solution for 6 hours (N = 6) all died within 12 hours after transplantation. These results suggest that normothermic perfusion can be used to reclaim DCD livers subjected to an additional period of cold ischemia during hypothermic storage.     

Extended preservation of non-heart-beating donor livers with normothermic machine perfusion

BACKGROUND: Non-heart-beating donor (NHBD) livers represent an important organ pool, but are seldom utilized clinically and require rapid retrieval and implantation. Experimental work with oxygenated perfusion during preservation has shown promising results by recovering function in these livers. This study compared sanguinous perfusion with cold storage for extended preservation of the NHBD liver in a porcine model. METHODS: Porcine livers were subjected to 60 min of in vivo total warm ischaemia before flushing, after which they were preserved by one of two methods: group 1 (n = 4), University of Wisconsin (UW) solution by standard cold storage for 24 h; group 2 (n = 4), oxygenated autologous blood perfusion on an extracorporeal circuit for 24 h. All livers were subsequently tested on the circuit during a 24-h reperfusion phase. RESULTS: Livers in group 1 showed no evidence of viability during the reperfusion phase with no bile production or glucose utilization; they also displayed massive necrosis. Livers in group 2 demonstrated recovery of function by synthetic function, substrate utilization and perfusion haemodynamics; these livers displayed less cellular injury by hepatocellular enzymes. All differences in parameters between the two groups were statistically significant (P < 0.05). These findings were supported by histological examination. CONCLUSION: Warm ischaemia for 1 h and simple cold storage (UW solution) for 24 h renders the liver non-viable. Oxygenated, sanguinous perfusion as a method of preservation recovers liver function to a viable level after 24 h of preservation.     

Enzymatic and morphological evaluation of the hepatic cytoprotective effect of somatostatin and octreotide during extended experimental liver preservation

Cytoprotective effects on the liver of somatostatin (ST) and octreotide (OT) have been previously described in normothermic ischemia-reperfusion models. The purpose of this study was an enzymatic and morphological assessment of hepatic cytoprotective effects during extended cold storage. Rat livers were washed in situ via the portal vein with University of Wisconsin solution (UW) UW+ST, or UW+OT. After 24 or 48 hours of cold ischemia time (CIT), livers were reperfused for 2 hours via the portal vein with oxygenated KHB at 37 degrees C using a nonrecirculating ex situ isolated perfusion system. Levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LDH), and creatinine kinase (CK) were assessed in the perfusate during ex situ isolated reperfusion. After a 24-hour cold ischemia time (CIT) ALT, LDH, and CK levels were significantly lower (P < .05) in the UW+ST and the UW+OT livers than the UW livers. After 48-hour CIT, AST, ALT, LDH, and CK levels were significantly lower (P < .05) in the UW+ST and the UW+OT livers than the UW livers. Histopathological examination revealed mild differences after 24-hour CIT but an evidently less ischemically damage organ after 48-hour CIT. With the limitations of an in vitro model, ST and OT showed enzymatic and morphological effects during extended liver preservation.     

供肝热缺血后对冷保存的耐受时限初步探讨

目的探讨供肝热缺血后耐受冷保存的安全时限。方法利用本组所建立的小型猪肝移植模型,设定供肝热缺血时间为20min,根据在UW液中的冷保存时间不同分为3组,分别冷保存12、16、20h,于肝移植术中及术后检测肝功能、肝脏病理、肝组织ATP含量、移植肝脏再灌注后微循环血流量及动物术后1周存活率。结果UW液冷保存12h组肝移植后小型猪1周内全部存活,而冷保存16、20h组存活率分别为20%、0%;随着冷保存时间的从12h延长到20h,ALT、AST逐渐上升,肝脏ATP含量、肝脏微循环血流量逐渐下降,形态学结果显示肝组织细胞变性、坏死及超微结构损害的程度逐渐加重。冷保存12h组与后两组上述指标存在显著性差异,生化及肝脏微循环指标的改变与病理结果及动物生存率相符合。结论在本实验条件下,热缺血时间为20min的供肝耐受冷保存的安全时限约为12h。     

Evaluation of rat liver apoptotic and necrotic cell death after cold storage using UW,HTK, and Celsior

BACKGROUND: The benefit of Celsior in liver graft preservation is controversial. In the isolated perfused rat liver model, we compared the effects of Celsior, University of Wisconsin (UW), and histidine-tryptophan-ketoglutarate (HTK) preservation solutions on liver cell death. METHODS: Rat livers were stored at 4 degrees C for 0, 8, 16, or 24 hr in either Celsior, UW, or HTK and reperfused for 90 min (37 degrees C). Bile secretion and perfusate levels of liver enzymes and histone-associated DNA fragments were measured. Apoptosis and oncotic necrosis were analyzed in biopsies by DNA gel electrophoresis, hematoxylin and eosin histology, and enzyme histochemistry for lactate dehydrogenase (LDH) and 5'-nucleotidase (5'-NT). RESULTS: Perfusate flow rate through the liver during perfusion did not significantly differ among preservation solutions. Bile secretion was best preserved in UW livers after 16-hr (versus HTK livers) and 24-hr storage (versus HTK and Celsior livers). Enzyme leakage from UW livers was lower compared with HTK livers after 8-hr storage (serum glutamic oxaloacetic transaminase [SGOT], LDH) and with Celsior and HTK livers after 16-hr (SGOT, LDH) and 24-hr storage (SGOT, serum glutamic pyruvic transaminase, LDH, purine nucleoside phosphorylase). In situ LDH and 5'-NT activities were best preserved in UW livers (up to 24 hr), whereas enzyme activities declined remarkably in HTK livers (after 8 hr) and Celsior livers (after 16 hr of cold storage). Although perfusate DNA fragment levels were repeatedly lowest from Celsior livers, apoptotic DNA laddering and the number of fragmented nuclei in hematoxylin and eosin sections was not different among livers after 8, 16, or 24 hr of storage. CONCLUSIONS: Celsior and UW are equally effective in preventing rat liver cell death after 0-16 hr of cold preservation as compared with the less effective HTK solution. After 24-hr cold storage, rat livers were best preserved in UW. Furthermore, there was no significant difference in mode of cell death (apoptosis or oncotic necrosis) after storage in any of the three solutions.     

Wash-out of the non-heart-beating donor liver: a comparison between ringer lactate, HTK, and polysol

The solution of choice for wash-out of non-heart-beating donor (NHBD) livers is histidine tryptophan ketoglutarate (HTK). This solution has a lower viscosity, due to absence of a colloid, and is less expensive as compared to the University of Wisconsin (UW) solution. A new preservation solution for machine perfusion was developed, named Polysol. In order to apply Polysol clinically in NHBD organ retrieval, the efficacy as a wash-out solution was investigated. METHODS: After a warm ischemic time of 30 minutes, the rat liver was washed out via the portal vein with 50 mL of either ringer lactate (RL), HTK or Polysol. After wash-out and harvesting, the liver was reperfused with Krebs-Henseleit buffer. Samples were taken to assess hepatocellular injury and liver function. RESULTS: Liver damage parameters were elevated in the RL group as compared to the HTK and Polysol groups. Liver/rat weight ratios were significantly lower after wash-out with Polysol. Overall, no differences were seen in ammonia clearance and bile production. In conclusion, wash-out of the NHBD liver with Polysol results in equal to improved reperfusion results as compared to HTK. Polysol is feasible as a wash-out solution in combination with machine perfusion using Polysol.     

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.