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.     

Comparison of UW solution and Euro-Collins solutions for cold preservation of human liver grafts

University of Wisconsin solution, a new organ preservation medium, is reported to extend the period of cold storage. In order to evaluate the efficacy of UW solution in human liver preservation we compared 58 donor liver grafts preserved in Euro-Collins (EC) solution. All livers were harvested in a similar manner. Donor and recipient characteristics in the two groups were comparable. The mean preservation time of the UW solution was 11.5 +/- 4.2 hr (range 3-20 hr), significantly longer than the EC mean preservation time of 4.9 +/- 1.6 hr (2-9.6 hr) (P = 0.0001). Evaluation of mean postoperative liver function tests and coagulation factors on days 1-7 showed no statistical difference between the two groups. There was one primary graft nonfunction in the EC group and none with the UW organs. Hepatic artery thrombosis was similar in each group. The incidence of early retransplantation was similar. Three-month graft survival was 81% in the UW group vs. 73% in the EC group. Patient survival at three months was 87% with the UW organs and 84% with the EC organs. We conclude that cold storage of liver grafts in the UW solution has allowed for significantly longer preservation, permitting transplantation to be performed under semielective conditions and procurement of organs from much further distances. Grafts stored in UW solution perform as well as those stored in Euro-Collins, with no significant difference in liver function abnormalities postoperatively.     

供肝切取与保存技术中几个关键环节的探讨

目的探讨提高和完善供肝切取与保存技术,提高器官利用率,减少肝移植术后近、远期并发症的发生。方法1995年5月至2005年6月我院实施了122例原位肝移植,采用腹腔器官联合快速切取技术进行了165例供肝和供肾联合切取,先行经肠系膜上静脉至门静脉插管,随即行腹主动脉插管,UW液原位灌洗。灌洗开始后优先处理胆道,用UW液经胆总管冲洗胆道。整块切取肝脏、双侧肾脏。回手术室进一步修剪,对变异的肝动脉(25例,20.5%)整形使之变为单支。结果165例供肝热缺血时间120~310 s,冷缺血时间260~840 min。移植肝通血20~30 min后均有金黄色胆汁分泌。术后均未发生原发性无功能和器官功能延迟。结论对于脑死亡的供者器官切取采取原位灌洗,整块切取及体外修整,可最大限度地缩短热缺血时间,有效避免变异血管损伤,进而提高供者器官的利用率。确切的胆道冲洗对避免肝内外胆管自溶和术后胆道狭窄非常重要。良好的供肝切取与保存是移植成功的保证,可有效地减少手术并发症,进而取得良好的疗效。     

Liver Transplantation Using University of Wisconsin or Celsior Preserving Solutions in the Portal Vein and Euro-Collins in the Aorta

Introduction

Orthotopic liver transplantation (OLT) is today the gold standard treatment of the end-stage liver disease. Different solutions are used for graft preservation. Our objective was to compare the results of cadaveric donor OLT, preserved with the University of Wisconsin (UW) or Celsior solutions in the portal vein and Euro-Collins in the aorta.

Methods

We evaluated retrospectively 72 OLT recipients, including 36 with UW solution (group UW) and 36 with Celsior (group CS). Donors were perfused in situ with 1000 mL UW or Celsior in the portal vein of and 3000 mL of Euro-Collins in the aortia and on the back table managed with 500 mL UW or Celsior in the portal vein, 250 mL in the hepatic artery, and 250 mL in the biliary duct. We evaluated the following variables: donor characteristics, recipient features, intraoperative details, reperfusion injury, and steatosis via a biopsy after reperfusion. We noted grafts with primary nonfunction (PNF), initial poor function (IPF), rejection episodes, biliary duct complications, hepatic artery complications, re-OLT, and recipient death in the first year after OLT.

Results

The average age was 33.6 years in the UW group versus 41 years in the CS group (P = .048). There was a longer duration of surgery in the UW group (P = .001). The other recipient characteristics, ischemia-reperfusion injury, steatosis, PNF, IPF, rejection, re-OLT, and recipient survival were not different. Stenosis of the biliary duct occured in 3 (8.3%) cases in the UW group and 8 (22.2%) in the CS (P = .19) with hepatic artery thrombosis in 4 (11.1%) CS versus none in the UW group (P = .11).

Conclusion

Cadaveric donor OLT showed similar results with organs preserved with UW or Celsior in the portal vein and Euro-Collins in the aorta.     

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.     

A basic consideration for porcine liver preservation using a novel continuous machine perfusion device

Introduction

The aims of this study were to compare extracellular and intracellular-type University of Wisconsin (UW) solutions for liver grafts and to assess oxygenation in this perfusion system.

Materials and Methods

The organ preservation system consisted of 3 circulating systems for the portal vein, hepatic artery, and maintenance of the perfusion solution. The portal vein or hepatic artery system had a roller pump, a flow meter, and a pressure sensor. In this study, we perfused livers with UW or extracellular type UW-gluconate at 4°C-6°C for 4 hours. The flow rates at the entrance were 0.5 mL/min/g liver in the portal vein and 0.2 mL/min/liver in the hepatic artery. Orthotopic liver transplantation was performed in pigs: group 1-a, grafts procured after acute hemorrhagic shock were preserved by a solution without O₂; group 1-b, grafts were preserved with O₂; group 2-a, grafts were perfused using intracellular type solution (UW); and group 2-b, grafts were perfused using extracellular-type solution (UW-gluconate).

Results

Effluent aspartate aminotransferase (AST) and lactate dehydrogenase (LDH) levels in group 1-b were lower than those in group 1-a. Survival rates in group 2-a and group 2-b were 1/4 and 3/3, respectively. Effluent AST and LDH levels in the perfusate of group 2-b were lower than group 2-a. Histological study revealed necrosis of hepatocytes and sinusoidal congestion in group 2-a.

Conclusion

A beneficial effect of extracellular-type solution with oxygenation in a novel continuous machine preservation system yielded well-preserved liver graft function.     

Cellular damage and early metabolic function of transplanted livers stored in Eurocollins or University of Wisconsin solution.

In a clinical setting, the effect of Eurocollins (EC) and University of Wisconsin solution (UW) on liver grafts were studied in the early reperfusion phase of liver transplantation. Blood samples were drawn before and after declamping of the portal vein in a group of 11 transplants with EC-perfused livers, and a group of 12 transplants with UW-perfused livers. Parenchymal damage was assessed by the LDH, AST, and ALT, and purine degradation by measuring the uric acid levels. Metabolic function was determined by the serum bile acids and the plasma amino acids, i.e. (valine + leucine + isoleucine)/(phenylalanine + tyrosine) ratio. Donor and pretransplant recipient parameters were almost identical. The cold ischemia time of both groups differed significantly. The results show the following: a significant difference between both the LDH and the uric acid levels in the two groups was revealed, with a smaller increase of the LDH levels and no increase of the uric acid levels in the UW group. Metabolic activity, as measured from the bile acids and the amino acid profile in the peripheral blood, was identical in both groups. We conclude that both EC-stored and UW-stored liver grafts show immediate metabolic function after reperfusion. The amount of metabolic function was equal in both groups, notwithstanding longer cold ischemia time in the UW group. In addition, more parenchymal damage occurred in the EC group.     

Postoperative recovery of mitochondrial function of the human liver graft procured and preserved with University of Wisconsin (UW) solution

Abstract. Changes in arterial blood ketone body ratio (KBR) were investigated in 47 human liver transplantations. Of the 20 grafts preserved with University of Wisconsin (UW) solution, 10 had a cold preservation period of less than 10 h (UWS group) and 10 of more than 10 h (UWL group). In 27 other cases, grafts were preserved with EuroCollins (EC) solution for less than 10h (EC group). In the EC group, KBR increased over 0. 7 within 6h after reperfusion of the graft in 17 cases (63%) and within 24 h in 7 cases (26%). In the 3 other cases, KBR failed to recover, and these patients underwent retransplantation. In the UW group, KBR recovered within 6 h in 13 cases (65%) and within 24 h in 7 cases (35%). There were no significant differences between the UWS and UWL groups. It is shown that the mitochondrial function of liver grafts preserved with UW solution can be well maintained even after extended preservation periods of more than 10 h.     

Postoperative recovery of mitochondrial function of the human liver graft procured and preserved with University of Wisconsin (UW) solution

Changes in arterial blood ketone body ratio (KBR) were investigated in 47 human liver transplantations. Of the 20 grafts preserved with University of Wisconsin (UW) solution, 10 had a cold preservation period of less than 10 h (UWS group) and 10 of more than 10 h (UWL group). In 27 other cases, grafts were preserved with EuroCollins (EC) solution for less than 10 h (EC group). In the EC group, KBR increased over 0.7 within 6 h after reperfusion of the graft in 17 cases (63%) and within 24 h in 7 cases (26%). In the 3 other cases, KBR failed to recover, and these patients underwent retransplantation. In the UW group, KBR recovered within 6 h in 13 cases (65%) and within 24 h in 7 cases (35%). There were no significant differences between the UWS and UWL groups. It is shown that the mitochondrial function of liver grafts preserved with UW solution can be well maintained even after extended preservation periods of more than 10 h.     

Modulation of pulmonary NA+ pump gene expression during cold storage and reperfusion

BACKGROUND: Reperfusion injury with pulmonary edema continues to be a major complication after lung transplantation. Alveolar fluid homeostasis is regulated by Na+/K+-ATPase activity on the basolateral surface of alveolar epithelial cells. Intact Na+/K+-ATPase is essential to the resolution of pulmonary edema. We characterized the effects of cold ischemia and reperfusion on expression of Na+/K+-ATPase mRNA and protein. METHODS: Baseline values for Na+/K+-ATPase mRNA and protein were determined from freshly harvested lungs with no cold storage time or reperfusion (group I). Group II lungs were analyzed after cold storage times of 12 or 24 hr without subsequent reperfusion. Group III lungs were analyzed after cold storage times of 12 or 24 hr with subsequent reperfusion. Lungs were flushed with either Euro-Collins (EC) or University of Wisconsin (UW) solution in each group. All samples were quantified for Na+/K+-ATPase mRNA and Na+/K+-ATPase protein. Physiological parameters including oxygenation and compliance were also measured. RESULTS: There were no significant differences in the level of mRNA and protein for samples that were cold stored without reperfusion (group II). With reperfusion (group III) there was a significant increase in the level of the Na+/K+-ATPase mRNA after 12 hr of storage for both EC and UW. After 24 hr of storage and subsequent reperfusion, lungs flushed with EC had significantly decreased Na+/K+-ATPase protein and mRNA, although lungs preserved with UW maintained their increased levels of Na+/K+-ATPase protein and mRNA. CONCLUSIONS: Our data suggest that ischemia-reperfusion injury results in an initial up-regulation of Na+/K+-ATPase mRNA. With prolonged injury in lungs preserved with EC, the level of the mRNA decreased with a corresponding decrease in the Na+/K+-ATPase protein. The different response seen in EC versus UW may be explained by better preservation of pump function with UW than EC and correlates with improved physiological function in lungs preserved with UW solution.     

Hepatic arterial buffer response fails to restore hepatic oxygenation after temporary liver dearterialization in canines

BACKGROUND: Hepatic artery thrombosis is a rare but extremely troublesome condition after liver transplantation. Recently, urgent arterial revascularization has been used as rescue therapy, leading to improved graft and patient survivals. Hepatic artery ligation produces a progressive reduction in portal vein blood flow. Theoretically, a hyperemic response may be expected following hepatic artery reperfusion (hepatic artery buffer response, HABR). In this study, we tested the hypothesis that HABR can maintain adequate liver oxygenation after temporary liver dearterialization. METHODS: Seven dogs (19.7 +/- 1.2 kg) subjected to 60 minutes of hepatic artery occlusion were observed for 120 minutes thereafter. Systemic hemodynamics was evaluated through Swan-Ganz and arterial catheters, and splanchnic perfusion by portal vein and hepatic artery blood flows (PVBF and HABF) via an ultrasonic flowprobe. Liver enzymes (ALT and LDH) and systemic and hepatic oxygen delivery (DO2hepat) were calculated using standard formulae. RESULTS: Hepatic artery occlusion induced a progressive reduction in PVBF and DO2hepat. A complete restoration of HABF after hepatic artery declamping was observed; however, the DO2hepat (33.3 +/- 5.9 to 16.5 +/- 5.9 mL/min) did not return to the baseline levels. CONCLUSION: Temporary hepatic artery occlusion induced a progressive decrease in portal vein blood flow during ischemia, an effect that continued during the reperfusion period. The hepatic artery blood flow was promptly restored after declamping. However, HABR was not able to restore hepatic oxygen delivery to baseline levels during the reperfusion period.     

The effect of temporary hepatic artery or portal vein occlusion in obstructive jaundice.

Hepatic hemodynamics before vascular occlusion and the effect of transient hepatic artery or portal vein occlusion on the liver were investigated in normal dogs and dogs with experimentally induced obstructive jaundice by measurement of hepatic tissue blood flow (HTBF), index of hemoglobin concentration (IHb), oxygen saturation (ISO2), serum glutamic pyruvic transaminase (SGPT) concentration, and malonaldehyde (MDA) concentration in liver tissue. Livers with obstructive jaundice had increased blood flow and a lower hemoglobin concentration compared with normal livers at baseline before vascular occlusion. Percentage change of ISO2 from baseline was higher than percentage change of HTBF after reperfusion in both normal and obstructive jaundiced liver, although they were decreased to almost similar proportions during vascular occlusion. MDA concentration in obstructive jaundice after reperfusion following vascular occlusion was higher than in normal liver. Furthermore, MDA concentration after reperfusion following hepatic artery occlusion was increased compared with after reperfusion following portal venous occlusion in obstructive jaundice. There was no evidence of massive liver necrosis which was newly developed by transient vascular occlusion. These results represent the pathological condition in the liver before transient vascular occlusion and after reperfusion in obstructive jaundice.     

小鼠肝动脉重建对长时间冷保存移植肝存活率的影响

目的研究小鼠肝动脉重建(hepatic arterial reconstruction,HAR)对长时间冷保存移植肝存活率的影响。方法同系雄性C57BL/6小鼠68只,分为冷保存时间(cold preservation time,CPT)1 h组、CPT4 h组、CPT8 h组、CPT16 h组、CPT16 h+HAR组(供、受体小鼠各一半)。小鼠供肝经门静脉灌注4℃UW液后保存。肝脏移植采用缝合法(肝上下腔静脉)和袖套法(门静脉、肝下下腔静脉)吻合,胆管采用内支架管重建法。小鼠HAR采用含供体肝动脉的腹主动脉与受体腹主动脉端侧吻合的方法。观察术后5组受体小鼠移植肝的存活时间,用组织学检查肝细胞损伤情况,用免疫组织化学法观察肝细胞再生功能。结果 CPT1 h、4 h、8 h组受体术后12 d移植物的存活率分别为7/7、10/10、9/9。CPT16 h组除1例小鼠存活外,其余均在移植术后36 h内死亡,存活率为10%(1/10),CPT16 h+HAR组受体90%(9/10)存活,两组存活率相比,差异有统计学意义(P0.01)。CPT1 h、4 h组的移植物组织损伤程度轻,CPT8 h组的移植物组织损伤程度较前两组严重,但肝细胞再生活跃。CRT16 h组的移植肝组织表现为广泛肝细胞空泡变性、坏死,肝细胞再生不明显。CPT16 h+HAR组仅有轻度的肝窦淤血,肝细胞空泡变性、坏死改变,肝细胞再生活跃。结论 HAR可提高长时间冷保存移植肝的存活率。     

Hemodynamic profiles during piggyback liver grafts using arterial or portal revascularization

BACKGROUND: The order of revascularization in human liver grafts is still discussed. This study tries to answer this question in terms of hemodynamic data. STUDY DESIGN: Fifty-nine patients were randomized in this study to compare hemodynamic data just before and 15 minutes after revascularization of liver grafts in relation to first hepatic artery (n = 29) or first portal vein (n = 30) revascularization procedure. RESULTS: Hemodynamic variations were significantly greater in the portal vein group than in the hepatic artery group in terms of mean arterial pressure, cardiac index, central venous pressure, pulmonary capillary pressure, and systemic vascular resistance. The latter decreased from 741.8 +/- 390.3 to 659.9 +/- 411.1 dynes/ cm5 (NS) in the hepatic artery group versus 807.7 +/-336.7 to 439.7 +/- 215 dynes/cm5 (p < 0.05) in the portal vein group. Clinical results and postoperative complications, graft characteristics, patient survival, and graft survival were not significantly different between the groups. CONCLUSIONS: Initial arterial revascularization of the liver graft leads to a more stable hemodynamic profile during revascularization of the liver graft after vascular unclamping. This technique is always feasible and has become our reference procedure.     

Biliverdin protects rat livers from ischemia/reperfusion injury

OBJECTIVE: To explore putative cytoprotective functions of biliverdin during hepatic ischemia/reperfusion (I/R) injury in rat models. MATERIAL AND METHODS: Male Sprague Dawley (SD) rat livers were harvested and stored for 24 hours at 4 degrees C in University of Wisconsin (UW) solution (n=18), and then perfused with blood for 2 hours on an isolated rat liver perfusion apparatus equipped for temperature (37 degrees C), pressure (13 cm H2O), and pH (7.3) maintenance. Biliverdin was added to the blood at concentrations of 10 and 50 micromol in two groups of six animals. Portal vein blood flow, bile production, and GOT/GPT levels were assessed serially. At the conclusion of the experiment, liver samples were collected for histologic evaluation using Suzuki criteria. RESULTS: BV exerted protective effects against liver I/R injury. Adjunctive biliverdin improved portal venous blood flow (mL/min/g) from the beginning of reperfusion (1.33+/-0.17 versus 0.98+/-0.15; P<.001) and increased bile production (mL/g) as compared with the control group (3.40 versus 1.88; P<.003). I/R-induced hepatocellular damage as measured by GOT/GPT release (IU/L) was diminished in the biliverdin group (91 versus 171 and 46 versus 144, respectively; P<.0001). Improved liver function by biliverdin was accompanied by preservation of the histologic structure as assessed by Suzuki criteria (3.7+/-1.4 versus 6.8+/-0.8 in untreated controls; P<.005). CONCLUSIONS: Biliverdin attenuates the ischemia/early reperfusion injury of rat liver grafts as assessed by hemodynamics, function, enzyme analysis, and histology. This study provides the rationale for novel therapeutic approaches using biliverdin to maximize the organ donor pool through the safer use of liver transplants despite prolonged periods of cold ischemia.     

Carolina rinse solution--a new strategy to increase survival time after orthotopic liver transplantation in the rat

Recently, we described a new solution, Carolina rinse, that prevents nonparenchymal cell injury in vitro after reperfusion of livers stored in University of Wisconsin cold solution (Currin RT, Toole JG, Thurman RG, Lemasters JJ. Transplantation 1990; 50: 1076). The present study was designed to examine the effect of Carolina rinse on graft survival in vivo. Unlike UW cold storage solution, which is high in potassium, Carolina rinse contains extracellular inorganic ions at levels similar to blood, a calcium channel blocker and a radical scavenger. Carolina rinse also contains fructose and mildly acidotic pH to reduce hypoxic cell death. Livers from Lewis rats were explanted, stored in UW cold storage solution under nonsurvival conditions, and rinsed with either 15 ml of Ringer's, UW solution, Carolina rinse, or Carolina rinse saturated with nitrogen prior to completion of implantation surgery. In the Ringer's rinse group, only 4% of recipients survived 30 days postoperatively. In this group, SGOT levels reached maximal values of about 5000 U/L. Survival was also poor (25%) when grafts were rinsed with UW solution. In the Carolina rinse group, however, 9 of 16 rats (56%) survived indefinitely, and maximal postoperative SGOT levels were reduced 3-fold. Liver injury indexed histologically was also decreased about 3-fold by Carolina rinse compared with the control group rinsed with Ringer's solution. Carolina rinse diminished postoperative sinusoidal endothelial cell damage assessed by electron microscopy and reduced carbon particle phagocytosis due to Kupffer cells significantly. Moreover, Carolina rinse diminished graft swelling and improved postoperative hepatic microcirculation compared with the Ringer's rinse group. Taken together, these results indicate that Carolina rinse is a superior alternative to Ringer's solution in vivo to protect liver grafts from reperfusion injury when removing high-potassium-containing cold storage solutions clinically prior to implantation.     

Hemodynamic interaction between portal vein and hepatic artery flow in small-for-size split liver transplantation

In split-liver transplantation, the entire portal flow is redirected through relatively small-for-size grafts. It has been postulated that excessive portal blood flow leads to graft injury. In order to elucidate the mechanisms of this injury, we studied the hemodynamic interactions between portal vein- and hepatic artery flow in an experimental model in pigs. Six whole pig liver grafts were implanted in Group 1 ( n=6) and six whole liver grafts were split into right and left grafts and transplanted to Groups 2 ( n=6) and 3 ( n=6), respectively. The graft-to-recipient liver volume ratio was 1:1, 2:3 and 1:3 in Groups 1, 2 and 3, respectively. Portal vein- and hepatic artery flows were measured with an ultrasonic flow meter at 60,120 and 180 min after graft reperfusion. Portal vein pressure was also recorded at the same time intervals. Graft function was assessed at 3,6h and 12h, and morphological changes at 12h after reperfusion. Following reperfusion, portal vein flow showed an inverse relationship to graft size, while hepatic artery flow was reduced proportionately to graft size. The difference was significant among the three groups ( P<0.05). Portal vein pressure was significantly higher in group 3, compared to groups 1 and 2 ( P<0.05). Hepatic artery buffer response was significantly higher in Group 3, compared to Groups 1 and 2 in relation to pre-occlusion values ( P<0.05). Split-liver transplantation, when resulting in small-for-size grafts, is associated with portal hypertension, diminished arterial flow, and graft dysfunction. Arterial flow impairment appears to be related to increased portal vein flow.     

Improved survival of orthotopic liver allograft in swine by addition of trophic factors to University of Wisconsin solution

Serum-free preservation media such as University of Wisconsin (UW) may cause tissue damage through trophic factor (TF) deprivation. This study evaluated whether the addition of TFs to UW solution improves liver graft quality after extended cold preservation time in pigs. UW solution was supplemented with epidermal growth factor, insulin-like growth factor-1, nerve growth factor-beta, bactenecin, and substance P to create TF-supplemented (TFS) UW. Orthotopic liver transplantation was performed after 18 hr of static cold storage at 4 degrees C in UW (n=7) or TFS-UW (n=7) solution. Recipients of grafts preserved with TFS-UW demonstrated significantly better 5-day survival (57%) than those preserved with UW alone (14%) (P<0.05). Adenosine triphosphate content in grafts preserved in TFS-UW was significantly higher than in grafts preserved in UW (17.4+/-5.0 vs. 4.8+/-1.2 nmol/mg protein, respectively) (P<0.05). This study showed that the addition of TFs to UW solution allowed a significant extension of cold ischemic time in pigs.     

Reperfusion rather than storage injury predominates following long-term (48 h) cold storage of grafts in UW solution: studies with Carolina Rinse in rat liver

Both storage injury and reperfusion injury have been reported in association with liver transplantation; however, which predominates is not clear. Therefore, these studies were designed to evaluate whether Carolina Rinse, which minimizes reperfusion injury following orthotopic liver transplantation in the rat, would be effective after long-term (48 h) storage of grafts in University of Wisconsin (UW) cold storage solution where sufficient time for development of storage injury exists. Livers were rinsed with either Ringer's solution or Carolina Rinse solution immediately prior to completion of implantation surgery. In the Ringer's group, 30-day survival was high following 24 h of cold storage (4/5) but was very low after 48 h (1/16). Importantly, survival was increased significantly (5/14) when grafts were rinsed with carolina Rinse following 48 h of cold storage. In both groups, parenchymal cells appeared normal by scanning electron microscopy, excluded trypan blue, and released SGOT at values only slightly above the normal range immediately (i. e., less than 5 min) after 48 h of cold storage. However, SGOT values rose steadily during the 1st hour postoperatively following reperfusion in the Ringer's rinse group and reached levels around 1,000 U/1. In addition, non-parenchymal cells were not labelled with trypan blue following storage, but significant labelling occurred within 1 h. Both SGOT release and nonparenchymal cell injury were reduced significantly when grafts were rinsed with Carolina Rinse prior to completion of surgery. Liver injury assessed histologically 24 h postoperatively was also reduced about 50% by Carolina Rinse. Oxidative stress appeared to be involved, since radical adducts, most likely of lipid origin, were trapped during the first 5 min after reperfusion with the spin trapping technique and detected by electron paramagnetic resonance spectroscopy. Lipid radical formation was reduced nearly completely on reperfusion by Carolina Rinse. Since Carolina Rinse improved survival of liver grafts following long periods of cold storage and reduced lipid radical formation and hepatocellular injury, we concluded that a reperfusion injury rather than a storage injury predominates following orthotopic transplantation of livers stored for long periods of time in cold UW solution.     

Histidine-tryptophan-ketoglutarate versus University of Wisconsin solution in living donor liver transplantation: Results of a prospective study

The grafts obtained from a living donor hepatectomy are perfused on the back table with either University of Wisconsin solution (UW) or histidine-tryptophan-ketoglutarate solution (HTK). The efficacy and safety of these solutions have been studied in cadaveric liver transplantation, however, there is no study comparing the two solutions in adult-to-adult living donor liver transplantation. In this study, UW and HTK were used in the perfusion of right living donor grafts. The grafts were perfused with a predetermined sequence and volume of one of the solutions. Liver biochemistries, complications, and graft and patient survival were analyzed. From January 2001 to September 2002, 30 grafts were alternately perfused with either UW (UW group) or HTK (HTK group). The perfusion was performed first via the artery and then via the portal vein with a predetermined volume. At a mean follow-up of 13 ± 7 months, no significant statistical difference between groups UW and HTK in posttransplantation liver biochemistries, complications, or patient and graft survival (84% and 80%, respectively) was observed. In conclusion, UW and HTK are equally effective and safe in the perfusion of the living donor liver grafts. HTK has a slight practical advantage over UW because it does not need to be flushed away before reperfusion of the graft and is less expensive. (Liver Transpl 2003;9:822-826.)