冷保存再灌注损伤对肝移植大鼠肝脏再生功能的影响及其调节机制

目的 探讨冷保存再灌注损伤对肝移植大鼠肝脏再生功能的影响及其调节机制.方法 雄性SD大鼠分为假手术组(6只)、UW 1 h肝移植组(48只)、UW 12 h肝移植组(48只).HE染色及透射电镜观察肝组织形态学变化;大鼠内皮细胞抗原和5-溴-2脱氧尿嘧啶核苷(BrdU)双染法检测肝实质细胞及肝窦内皮细胞(SECs)的增殖状况;免疫组织化学法检测VEGF及其受体flt-1、flk-1的表达;RT-PCR法检测flt-1 mRNA的表达.计量资料采用单因素方差分析或t检验.结果 UW 12 h组肝实质细胞和SECs的BrdU标记指数均显著高于UW 1 h组(F=61.45,41.4,P<0.05).UW 1 h组和UW 12 h组大鼠肝实质细胞BrdU标记指数于48 h达高峰,而SECs的BrdU标记指数分别于术后72、96 h达高峰.UW 1 h组和UW12 h组大鼠肝移植术后VEGF表达较假手术组明显增强.UW 1 h组flt-1及flk-1表达较假手术组明显增强,阳性表达主要位于SECs,其表达高峰与SECs增殖高峰一致.UW 12 h组flt-1 mRNA表达较假手术组明显减弱(F=141.67,P<0.05).结论 flt-1表达下调是导致冷保存肝移植大鼠SECs再生高峰延迟,从而减缓移植肝脏功能恢复的重要原因.     

Protection by vascular endothelial growth factor against sinusoidal endothelial damage and apoptosis induced by cold preservation

BACKGROUND: It is well known that sinusoidal endothelial cell (SEC) damage during cold preservation of liver tissue is closely involved in early graft failure. The objective of this study was to investigate the involvement of apoptosis in the SEC damage induced by cold preservation and to demonstrate the protective effect of vascular endothelial growth factor (VEGF) on SEC injury, including apoptotic changes. METHODS: Isolated SECs and liver tissue of Wistar rats were cold-preserved in University of Wisconsin (UW) solution, and the protective effect of VEGF was then investigated. Isolated SECs were cultured for 24 hr, and divided into the following 3 groups: Group A, in which the cells were cultured for an additional 27 hr, Group B, in which the cells were cold-preserved in UW solution for 3 hr, and then recultured for 24 hr, and Group C, in which 20 ng/ml of VEGF was added to both the culture medium and the UW solution of cells cultured according to the Group B protocol. Each group of SECs was morphologically examined using the phase contrast microscopic method and the transmission electron microscopic method (TEM), and quantitatively analyzed using the WST-1 assay. Rat livers were cold-preserved in UW solution and divided into the VEGF(+) group and the VEGF(-) group, depending on whether VEGF was added or not. Each group of livers were analyzed by scanning electron microscopic method (SEM) after 24 hr of preservation. The hyaluronic acid uptake rate (HUR) was also determined after 6 hr of preservation. After 24 hr of preservation and 6 hr of reperfusion, tissues were examined by TEM and by the terminal deoxynucleotidyl transferase d-uridine triphosphate nick end labeling (TUNEL) assay. RESULTS: The phase contrast microscopic method and the WST-1 assay showed a protective effect of VEGF against the injury to isolated SECs during cold preservation and subsequent reculturing. Apoptosis was detected immediately by TEM after isolation of SECs, and the number of apoptotic cells increased with the incubation time. This increase was accelerated after cold preservation. The scanning electron microscopic method and the hyaluronic acid uptake rate showed a protective effect of VEGF against SEC damage in the cold-preserved livers. In the liver tissue, the TEM and the TUNEL assay detected apoptosis of SECs only after cold preservation and subsequent reperfusion. VEGF suppressed the apoptosis of SECs induced by cold preservation in both isolated cells and liver tissue. CONCLUSIONS: We demonstrated that SEC damage in the cold preservation of liver tissue was caused mainly by apoptosis, which required subsequent reperfusion. Moreover, isolated SECs showed spontaneous occurrence of apoptotic changes during culture, and these changes were accelerated by the preceding cold preservation. This is the first report to demonstrate the apoptotic changes of SECs seen here were inhibited by VEGF.     

冷保存供肝肝移植大鼠肝窦内皮细胞损伤机制的研究

目的 探寻肝移植大鼠肝窦内皮细胞(SEC)损伤的详细过程、方式及机制,为冷保存再灌注损伤的保护研究开辟新的途径.方法 雄性SD大鼠随机分为假手术组(n=6)、UW 1 h肝移植组(n:48)、Uw 12 h肝移植组(n=48).大鼠原位肝移植采用双袖套法,分别于术后不同时相点采取血液及组织标本,检测血清丙氨酸氨基转移酶(ALT)及透明质酸(HA)水平;HE染色观察肝脏病理学变化;TUNEL法检测凋亡,免疫组化法检测Bcl-2及Cleaved Caspase-3的表达状况.结果 UW 1 h、UW 12 h组肝移植后血清ALT、HA均较假手术组明显升高(P<0.05),UW 12 h组又明显高于Uw 1 h组(P<0.05).UW 12 h组ALT水平于术后6 h达高峰,而HA水平却在术后1 h、24 h呈双峰表现.Uw 12 h组首先出现SEC的凋亡继而出现肝细胞的坏死,且UW 12 h组细胞凋亡指数(apoptosis index,AI)明显高于UW 1 h组(P<0.01).两组大鼠SEC的AI均于术后6 h达高峰,与血中ALT的高峰时相点一致.肝移植术后Bcl-2表达明显减弱(P相似文献   

大鼠供肝冷保存时间延长损伤移植肝肝细胞和肝窦内皮细胞

目的 探讨供肝冷保存时间与肝移植后肝细胞和肝窦内皮细胞（SEC）损伤的关系。方法 选取健康雄性SD大鼠作为供、受者，建立原位肝移植（OLT）模型。随机分为3组，冷保存1h组（H=48）：供肝获取后，置于4C的冷保存液中保存1h，再行OLT。冷保存12h组（n=48）：供肝获取后，置于4℃的UW液中保存12h，再行OLT。对照组（H=6）：大鼠只打开腹腔，不进行移植。前2组分别于术后1、6、12、24、48、72、96和168h采取血液及组织标本，对照组仅在开腹时取血液及组织标本，检测各组、各时点血清丙氨酸转氨酶（ALT）、天冬氨酸转氨酶（AST）及透明质酸（HA）的水平；观察移植肝的病理形态学变化，透射电镜观察其超微结构改变；原位末端脱氧核糖核酸转移酶标记法（TUNEL）检测移植肝细胞的凋亡情况；观察术后168h时的大鼠存活率。结果 冷保存1h和冷保存12h组肝移植后各时点血清ALT、AST及HA均较对照组明显升高（P〈0．05），并且冷保存12h组又明显高于冷保存1h组（P〈0．05）。冷保存12h组术后24h移植肝组织出现片状坏死，而冷保存1h组病理学改变不明显。冷保存12h组肝窦内皮细胞凋亡指数（AI）明显高于冷保存1h组（F=63．58，P〈0．01），两组大鼠移植肝组织均于术后6h出现凋亡高峰，且肝窦内皮细胞的凋亡指数明显高于肝细胞。冷保存1h组和冷保存12h组大鼠肝移植后168h时的存活率分别为100％和50％，两组比较，差异有统计学意义（F=6．39，P〈0．05）。结论 肝移植后肝细胞和肝窦内皮细胞的损伤程度与冷保存时间密切相关。肝窦内皮细胞对冷保存及再灌注损伤的敏感性高于肝细胞，其损伤方式以细胞凋亡为主。     

Fate of hepatocyte and sinusoidal lining cell function and kinetics after extended cold preservation and transplantation of the rat liver

We investigated the chronological profile of graft damage and recovery after liver cold ischemia-reperfusion (I/R) injury, with particular attention to the role of apoptosis on hepatocyte and sinusoidal endothelial cell (SEC) damage. Male Lewis rats underwent rearterialized orthotopic liver transplantation using grafts subjected to a short (University of Wisconsin [UW] solution for 1 hour [UW1h]) and prolonged period (UW16h) of cold preservation. Experiments were performed immediately after preservation and 4 hours, 24 hours, 3 days, and 7 days after reperfusion. At each time, graft function, incidence of apoptotic cells, expression of the epitope recognized by a monoclonal antibody specific to rat SECs (SE-1), and incidence of proliferating cells were estimated. In the UW16h group, the proportion of apoptotic SECs was markedly elevated at 4 hours. The incidence of hepatocyte apoptosis was very low, although massive hepatocyte necrosis was evident at 24 hours. The incidence of proliferating hepatocytes and SECs peaked at 3 days, then returned to normal by 7 days. SE-1 expression was reduced immediately after preservation, followed by a marked reduction at 4 and 24 hours after reperfusion, and expression returned to normal by 7 days. Although SEC apoptosis was induced in the early phase of cold I/R injury, hepatocyte damage developed without the occurrence of apoptosis. Regeneration of both hepatocytes and SECs after cold I/R injury peaked at 3 days and was complete by 7 days, whereas functional recovery of these cell populations was complete 3 days after reperfusion. (Liver Transpl 2002;8:370-381.)     

Morphologic alteration of hepatocytes and sinusoidal endothelial cells in rat fatty liver during cold preservation and the protective effect of hepatocyte growth factor

BACKGROUND: Fatty liver grafts are considered to be one of the main factors of primary nonfunctioning graft in transplantation. We investigated here, the hepatic damage during cold preservation in a rat fatty liver model by ultrastructural observation, and examined the effect of human recombinant hepatocyte growth factor (hrHGF) on amelioration of the cold-preserved graft condition. METHODS: Wistar rats were fed a choline-deficient diet (CDD) for 7 days. Livers were stored in cold University of Wisconsin (UW) solution for 0, 4, and 24 hr. We evaluated the ultrastructural alteration of the hepatocytes, sinusoidal architecture, and endothelial cells (SECs) by scanning and transmission electron microscopy. Ex vivo, we measured alanine aminotransferase (ALT) in first effluent as an index of hepatocyte injury and the hyaluronic uptake rate (HUR) as that of SEC damage. We injected hrHGF into rats fed CDD for 7 days through the portal vein and also added it to the UW solution to determine whether or not the agent ameliorated the hepatic damage in cold-preserved fatty livers. RESULTS: In rats fed CDD for 7 days, the lesion occupied by fat deposits appeared to enlarge with the duration of cold preservation leading to the disarrangement of sinusoidal architecture. Furthermore, sinusoidal endothelial damage, in which gaps, blebs, microvilli, and sinusoid denudation were detected, appeared to be more severe in these livers than in the corresponding control livers. ALT significantly increased in the 4-hr cold-preserved livers of rats fed CDD for 7 days. HUR decreased with 4-hr cold preservation and/or with CDD feeding. Administration of hrHGF prevented the expansion of fatty droplets and reduced SEC injury as detected by morphological observations. Increase of ALT in first effluent was inhibited to about one fourth the level observed in the 4-hr cold-preserved livers of rats fed CDD. Moreover, HUR significantly increased with the pretreatment of hrHGF. CONCLUSION: The hepatic injury in both hepatocytes and SECs in cold-preserved fatty liver graft developed more rapidly and severely than in the corresponding controls and demonstrated a protective effect of hrHGF.     

The impairment of hepatocytes and sinusoidal endothelial cells during cold preservation in rat fatty liver induced by alcohol and the beneficial effect of hepatocyte growth factor

A fatty liver resulting from alcohol intake is often unattractive for grafting. In this study, we investigated the impairment of hepatocytes and sinusoidal endothelial cells (SECs) during cold preservation of alcohol-induced fatty liver and examined the efficacy of human recombinant hepatocyte growth factor (hrHGF). Rats were fed an alcohol diet. We performed histological examinations of the hepatocytes and observed the ultrastructural alteration of the SECs. Additionally, we measured hepatic transaminase and peroxidative lipids for hepatocellular injury and the hyaluronic acid uptake rate (HUR) to determine SEC injury. We added hrHGF to University of Wisconsin (UW) solution to assess the protective effect of the agent. Numerous fatty deposits were observed in ethanol-induced fatty livers. These grew with the duration of cold storage. Hepatic transaminases of the effluents increased during cold preservation in the livers of alcohol-treated rats. Additionally, peroxidative lipids in the effluents increased during cold preservation in the livers of alcohol-treated rats, whereas they were undetectable in non-alcohol-treated rat livers. The sinusoidal endothelium had severely deteriorated in the livers of alcohol-treated rats. Further, the HUR decreased with ethanol treatment and/or cold preservation. The addition of hrHGF suppressed the increase of hepatic transaminase in the effluent of cold-preserved alcohol-treated livers. Peroxidative lipids in the same effluents were undetectable. In fatty livers, both hepatocytes and SECs received severe damage during cold preservation. Furthermore, we demonstrated that hepatocellular injury was significantly inhibited by hrHGF.     

Apoptosis of sinusoidal endothelial cells occurs during liver preservation injury by a caspase-dependent mechanism.

BACKGROUND: Cold ischemia/warm reperfusion (CI/WR) liver injury remains a problem in liver transplants. Sinusoidal endothelial cells (SEC) are a target of CI/WR injury, during which they undergo apoptosis. Because caspase proteases have been implicated in apoptosis, our aim was to determine whether liver CI/WR injury induces a caspase-dependent apoptosis of SEC. METHODS: Rat livers were stored in the University of Wisconsin (UW) solution for 24 hr at 4 degrees C and reperfused for 1 hr at 37 degrees C in vitro. Apoptosis was quantitated using the TUNEL assay, and caspase 3 activation determined by immunohistochemical analysis. Rat liver orthotopic liver transplants (OLT) were also performed using livers stored for 30 hr. RESULTS: Terminal deoxynucleotide transferase-mediated dUTP nick end labeling (TUNEL) positive hepatocytes were rare and did not increase during CI/WR injury. In contrast, TUNEL positive SEC increased 6-fold after reperfusion of livers stored under cold ischemic conditions, compared with controls or livers stored but not reperfused. Immunohistochemical analysis demonstrated active caspase 3 only in endothelial cells after CI/WR injury. When IDN-1965, a caspase inhibitor, was given i.v. to the donor animal and added to UW solution and the reperfusion media, TUNEL positive endothelial cells were reduced 63+/-11% (P<0.05). Similarly, the duration of survival after OLT was significantly increased in the presence of the inhibitor. CONCLUSION: During liver CI/WR injury: 1) selective apoptosis of endothelial cells occurs; 2) caspase 3 is activated only in endothelial cells; and 3) a caspase inhibitor reduces endothelial cell apoptosis and prolongs animal survival after OLT. The pharmacologic use of caspase inhibitors could prove useful in clinical transplantation.     

Hydrodynamic plasmid DNA gene therapy model in liver transplantation

BACKGROUND: There is great interest in the field of transplantation to genetically modify grafts to decrease preservation injury or allograft rejection. Although adenoviral gene transfer has been effective in experimental liver transplantation, viral toxicity and safety concerns limit potential use in clinical trials. Therefore, the purpose of this study was to develop a model of nonviral gene transfer in the liver transplant setting, allowing for efficient transgene expression. MATERIALS AND METHODS: Orthotopic syngeneic rat liver transplantation was performed with 3 h cold ischemia using University of Wisconsin (UW) preservation. A hydrodynamic gene transfer technique was developed where plasmid DNA was delivered to the liver graft by ex vivo rapid infusion of DNA in UW via the IVC with other vessels clamped. Expression plasmids for the marker genes luciferase and secreted human alpha1-antitrypsin (alpha1-AT) were used. Hepatic injury was assessed by graft histology and liver transaminases. Transgene expression was determined by hepatic luciferase relative light units activity (RLU) and serum alpha1-AT protein levels. Variables examined included the effect of (a) volume injected on the intravenous pressure in the liver graft; (b) injury to the liver, as measured by hepatic enzymes and histopathology; (c) variable expression between lobes; (d) volume of UW that the plasmid is administered in; (e) amount of DNA plasmid; (f) type of the promoter used; (g) clamp time; as well as (h) the time course of the marker gene expression. RESULTS: Control rats underwent standard orthotopic syngeneic rat liver transplantation and had no detectable hepatic luciferase activity or serum human alpha1-AT. The optimal DNA plasmid dose was found to be 400 mug/liver graft, as there was no increase in the luciferase expression by increasing the dose. Furthermore, cytomegalovirus promoter yielded greater expression than Rous sarcoma virus. A high injection pressure gradient allowed for more efficient transgene expression, but produced greater liver injury shown by elevated transaminases and centrilobular necrosis. Lowering injection volume from 75 to 50% of graft weight decreased liver injury by 4.5-fold. Although higher UW injection volumes were associated with increased expression, volumes of only 50% led to luciferase expression up to 10,000,000 RLU/mg; this expression was homogeneous between the different liver lobes. Human alpha1-AT was detected in recipient blood as early as 6 h, peaked at 24 h, and remained high for 5 days. CONCLUSIONS: We have developed a nonviral gene transfer technique where hydrostatic pressure across the cold-preserved liver vascular bed allows for efficient plasmid DNA delivery. This simple strategy should prove useful to genetically modify liver grafts in the transplantation setting.     

HIV-1反式激活蛋白-血红素氧合酶-1融合蛋白对大鼠供肝冷保存期肝细胞凋亡的影响

Objective To study the effects of TAT-HO-1 fusion protein,HIV-1 transactiviting protein (TAT) and heme oxygenase-1 (HO-1),on hepatic cell apoptosis of rat donors in cold storage stage.Methods Forty-eight male SD rats were randomly divided into two groups.Rat livers were flushed and preserved with 4℃ HTK solution containing(group P) or uncontaining(group C) 50 mg/L of TAT-HO-1.The preserved solution and hepatic tissue were collected at 0,6,12,18 h of cold storage stage.TAT-HO-1 transducing into liver,alanine aminotransferase(ALT) level in preserved solution,hyaluronic acid(HA) level and the expression of caspase-3 in hepatic tissue,and the apoptotic index (AI) of hepatocytes and sinusoidal endothelial cells (SECs) were measured or detected.Results ALT level in preserved solution,HA level and the expression of caspase-3 in hepatic tissue,and the AI of hepatocytes and SECs increased time-dependently in cold storage stage in both groups (P＜0.05),with lower increasing extent in group P than that in group C (P＜0.05) at 6h,12h and 18h of cold storage stage.A stronger accumulation of HO-1 staining was also detected at the same time-points in group P than that in group C(P＜0.05).Conclusion TAT-HO-1 may transduce efficiently into rat livers,exerting protective effects on both hepatocytes and SECs during cold storage stage.Protein transduction technology may be a novel therapeutic means to reduce donor liver injury in preservation period for transplantion.     

大鼠肝脏保存中不同器官保存液对肝细胞凋亡的影响

目的 研究３种目前国内常用的器官保存液对供肝细胞凋亡的影响。方法 分别用ＵＷ液、ＨＣ－Ａ液和ＷＭＯ－１号液灌洗并保存大鼠肝脏,于保存后０、１２、２４ｈ用原位末端标记法检测供肝细胞凋亡情况,并将保存２４ｈ的肝及行大鼠原位全肝移植,观察受者的３ｄ存活率。结果 ３种保存液保存的肝脏均在保存１２ｈ时出现细胞凋亡,ＨＣ－Ａ液级瑟ＷＭＯ－１号液组的凋亡指数（ＡＩ）高于ＵＷ液组（Ｐ〈０．００１）,而ＨＣ－Ａ液组     

Cyclosporin-A does not prevent cold ischemia/reperfusion injury of rat livers

Cyclosporin-A (CsA) has been reported to protect livers from warm ischemia/reperfusion (I/R) injury. To study if CsA has also a protective effect on cold I/R injury, two models were used: the isolated perfused rat liver (IPRL) and the orthotopic rat liver transplantation (ORLT). (1) IPRL: Livers were preserved for 24 h (5°C) in University of Wisconsin (UW) solution alone (group 1), with CsA (400 nM) dissolved in dimethylsulfoxide (50 μM) (group 2), and with dimethylsulfoxide (DMSO) alone (group 3). Livers were reperfused for 60 min (37°C) (n = 8/group). Cell necrosis was evaluated by trypan blue uptake and apoptosis by laddering and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay, and by caspase-3 activation. Marked and similar sinusoidal endothelial cell necrosis was found in the three groups while apoptosis was found similarly deceased in groups 2 and 3 compared with group 1. (2) ORLT: Donors received either CsA (5 mg/kg) or corn oil 24 h before transplantation. Recipients were sacrificed after 240 min; cell necrosis and apoptosis were then evaluated. No difference was found between treated and control groups. The current data strongly suggest that CsA has no protective effect on hepatic cold I/R injury. Hepatocyte apoptosis can be reduced by antioxidants, as occurred with DMSO, but introduction of CsA does not provide additional protective effect.     

冷保存对肝移植术后肝内胆管微循环的影响

目的探讨供肝冷保存对肝移植术后肝内胆管微循环的影响。方法实验大鼠随机分为假手术组（SO组）、供肝冷保存1h组（CP1h组）、供肝冷保存24h组（CP24h组）。采用重建肝动脉的大鼠肝移植模型。在肝移植术后的不同时间点,观察肝内胆管组织损伤程度;经肝动脉注入微球,光镜下行肝组织汇管区内微球计数;采用间接免疫荧光双染技术检测肝组织汇管区微小血管内皮细胞eNOS、El＂-1和ICAM-1的表达,并采用原位杂交技术检测其mRNA的表达。结果冷保存再灌注可引起肝内胆管结构改变,冷保存时间越长损害程度越重。冷保存再灌注可引起肝组织汇管区内微球数量增加,且时间越长微球数量增加越明显。冷保存再灌注可引起汇管区微小血管内皮细胞eNOS蛋白及mRNA表达水平降低,而ET-1和ICAM-1的蛋白及mRNA表达水平升高。结论冷保存可引起大鼠移植肝脏肝内胆管微循环及其内皮细胞功能明显改变,微循环障碍可能在肝内胆管冷保存再灌注损伤中起重要作用。     

肝移植术中应用S-腺苷-L-蛋氨酸对供肝热缺血损伤的影响

目的探讨术中S-腺苷-L-蛋氨酸（SAMe）加入UW液和血浆冲洗液对热缺血损伤供肝及其恢复的影响。方法建立10min热缺血大鼠肝移植模型，分为A组：UW液灌注＋乳酸钠林格氏液冲洗、B组：UW液灌注＋血浆冲洗、C组：SAMe加入UW液灌注＋血浆冲洗和D组：UW液灌注＋SAMe加入血浆冲洗4组，观察肝组织组织病理学变化和电子显微镜下超微结构变化，并检测血清AST和透明质酸。结果C组和D组术后24h血清AST均低于B组（P〈0．05）。A组术后3h和24h血清HA高于B组（P〈0．05），B组复流后3h及24h血清HA均高于C组和D组（P〈0．05）。组织病理学表现B组复流后3h和24h肝细胞损伤和微循环紊乱较C组和D组明显；超微结构表现，A组复流后3h线粒体肿胀，肝窦内皮细胞肿胀，细胞核不规则，可见内皮细胞凋亡，大部分区域肝窦状隙明显狭窄，内皮层结构模糊，红细胞淤积，受压变形，白细胞附壁，可见内皮层完整性破坏；复流后24h，可见线粒体嵴断裂，核融解。B组内皮细胞损伤较A组轻，C组和D组超微结构表现微循环紊乱和肝细胞损伤表现较B组轻。结论供肝切取术中UW液中加入SAMe灌注保存，血浆冲洗液中加入SAMe可改善热缺血供肝微循环，减轻缺血再灌注损伤，并减轻肝细胞热缺血损伤，有利于10min热缺血供肝功能的恢复。     

Addition of a water-soluble alpha-tocopherol analogue to University of Wisconsin solution improves endothelial viability and decreases lung reperfusion injury.

BACKGROUND: Reperfusion injury following lung preservation has been associated with free radical formation and subsequent endothelial cell damage. Trolox is a water-soluble analogue of the free radical scavenger alpha-tocopherol. We hypothesized that addition of this form of vitamin E to University of Wisconsin (UW) solution would decrease reperfusion injury and improve lung function after cold ischemic preservation. MATERIALS AND METHODS: Bovine aortic endothelial cells were cultured and stored at 4 degrees C for 12, 24, and 48 h in UW or UW + Trolox (UWT). Endothelial cell viability after storage was assessed by dimethylthiazole tetrazolium cytotoxicity assay. An isolated rat perfused lung (IPL) model was used and lungs were flushed with the respective solutions with cold storage times of 6 and 12 h. Following storage, the lungs were reperfused with fresh blood and lung function was assessed by blood gas analysis, alveolar-arterial gradient, and compliance. RESULTS: There was no difference in endothelial cell viability between UW and UWT after 12 or 24 h; however, UWT had higher endothelial cell viability than UW with 48 h of cold ischemic storage. Using the IPL model, the pO2 was higher with UWT than UW after 6 and 12 h of cold ischemia. The alveolar-arterial oxygen difference was significantly lower for UWT versus UW at 6 h. UWT provided increased compliance at 6 and 12 h of ischemia. CONCLUSIONS: The addition of a water-soluble vitamin E analogue to UW solution resulted in increased endothelial cell viability after prolonged storage and improved whole lung preservation in the postreperfusion period as evidenced by higher oxygenation and increased compliance. These results are clinically relevant as the lung is extremely sensitive to reperfusion injury and UW solution is being increasingly used in lung transplantation and remains the predominant solution in abdominal organ transplantation.     

Sinusoidal lining cell damage: the critical injury in cold preservation of liver allografts in the rat

We have previously defined viability limits in a rat transplantation model. All liver allografts stored in a simple preservation solution (NaCl 0.9%, CaCl2 2 mM) at 4 degrees C for 4 hr or at 37 degrees C for 1 hr were viable upon transplantation, but all those stored at 4 degrees C for 8 hr or at 37 degrees C for 2 hr were nonviable. Only cold-preserved, nonviable livers showed increased vascular resistance, platelet trapping and an initially low, but then high, rise in aspartate transaminase (AST) upon reperfusion, all suggesting injury to the microcirculation, with secondary injury to the hepatocyte. In the present study, we investigated the morphological changes that occur in livers stored for the defined critical times, using light and electron microscopy after perfusion-fixation. Accurate and reproducible identification of specimens as belonging to viable or nonviable and warm- or cold-preserved could be made in this way. Preservation in the cold first resulted in reversible changes consisting of cellular swelling, alterations of intracellular organelles, and partial denudation of the sinusoidal lining (cold-preserved viable group). Later, under conditions of nonviable cold preservation, detachment of cell bodies of sinusoidal lining cells with nuclear changes and almost complete denudation of the sinusoidal lining was observed. Endothelial cells of larger vessels were only injured mildly. In contrast, under conditions of warm preservation, changes involving mitochondria and later nuclei were found in hepatocytes, and blebbing was more extensive. Endothelial cells were spared relatively. We also examined livers stored in isotonic citrate solution at 4 degrees C for 8 hr and 16 hr, the critical times determined for this solution in another model of rat liver transplantation. The findings were very similar to storage in saline with respect to the changes in the sinusoidal lining cells after cold preservation for the two critical times. The results provide convincing evidence of a qualitative difference between warm and cold preservation injury, with relatively selective damage to hepatocytes or sinusoidal lining cells, respectively. Endothelial damage represents the primary event, resulting in the loss of organ viability following hypothermic storage. Thus morphology may serve as a useful viability marker after preservation.     

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.     

ET-Kyoto solution plus dibutyryl cyclic adenosine monophosphate is superior to University of Wisconsin solution in rat liver preservation

ET-Kyoto solution (ET-K) is an extracellular-type organ preservation solution containing the cytoprotective disaccharide, trehalose. A previous study reported the supplement of dibutyryl cyclic adenosine monophosphate (db-cAMP) in conventional ET-K to attenuate lung ischemia-reperfusion injury. In this study, the efficacy of this modified ET-K for liver preservation was investigated by comparison with University of Wisconsin solution (UW). ET-K was supplemented with db-cAMP (2 mmol/L). Lewis rats were randomly assigned to two groups, and liver grafts were flushed and stored at 40C for 24 h with ET-K or UW before syngeneic liver transplantation. The graft function and histological changes at 4 h posttransplant as well as 7-day survival were evaluated. Recipient rat survival rate was significantly higher in the ET-K group than in the UW group. Preservation in ET-K resulted in a significant reduction in serum parenchymal transaminase level and promotion of bile production in comparison with UW. The serum hyaluronic acid level, an indicator of sinusoidal endothelial cell injury, was significantly lower after ET-K preservation than that in UW. Histologically, at 4 h after transplantation, the liver grafts preserved in UW solution demonstrated a greater degree of injury than those in ET-K, which appeared to be apoptosis, rather than necrosis. The continuity of the sinusoidal lining was better preserved in ET-K than in UW. In conclusion, ET-K supplemented with db-cAMP is superior to UW in rat liver preservation. This modified ET-K might therefore be a novel candidate for the procurement and preservation of multiple organs.     

阿霉素诱导热休克蛋白72对大鼠肝脏冷缺血-再灌注损伤的保护作用

目的观察阿霉素（DXR）预处理诱导大鼠肝脏热休克反应在肝脏长时间冷缺血一再灌注损伤中对肝细胞的保护作用。方法供体大鼠术前按1mg／kg由外周静脉注射DXR（DXR组）,对照组注射生理盐水。48h后行肝脏原位冷灌注,获取肝脏后将其在4℃UW液中保存48h,然后行原位肝移植,再灌注1、3h。逆转录-聚合酶链反应法测定肝组织肿瘤坏死因子-α（TNF-α）mRNA、中性粒细胞化学趋化性细胞因子（CINC）mRNA、巨噬细胞炎症蛋白-2（MIP-2）mRNA的表达,蛋白质印迹法测定肝组织热休克蛋白72（HSP72）、核转录因子-κB（NF-κB）的表达,测定血清谷丙转氨酶、TNF-α、CINC、MIP-2水平。同时观察7d生存率。结果DXR组TNF-α mRNA、CINCmRNA、MIP-2mRNA的表达均低于对照组。DXR组HSP72表达显著,对照组基本无表达;DXR组NF-κB无表达,对照组显著表达。DXR组血清TNF-α、CINC、MIP-2显著低于对照组（P〈0．05）。DXR组7d生存率为50％,对照组为0（P〈0．05）。结论DXR预处理大鼠供肝可使肝脏长时间冷缺血-再灌注损伤显著减轻;HSP72的诱导可抑制NF-κB激活导致的炎症反应,对肝实质细胞提供保护作用。     

The caspase inhibitor IDN-6556 prevents caspase activation and apoptosis in sinusoidal endothelial cells during liver preservation injury

Cold ischemia (CI)-warm reperfusion (WR) liver injury remains a problem in liver transplantation. CI-WR initially causes sinusoidal endothelial cell (SEC) apoptosis through a caspase-dependent mechanism. We previously showed that the caspase inhibitor IDN-1965 prevents CI-WR-induced SEC apoptosis. However, this agent required to be administered to the donor, preservation solution, and recipient for efficacy. Here, we show that a second-generation caspase inhibitor, IDN-6556, effectively prevents CI-WR-induced SEC injury when added only to University of Wisconsin (UW) cold storage media. Rat livers were stored in UW solution for 24 hours at 4 degrees C and reperfused for 1 hour at 37 degrees C. Apoptosis was quantitated using terminal deoxynucleotide transferasemediated deoxyuridine triphosphate nick end labeling (TUNEL) assay and caspase 3 activation determined by biochemical measurement and immunohistochemical analysis. Pan-caspase inhibitors (IDN-8066, IDN-7503, IDN-7436, IDN-1965, and IDN-6556) were applied at preischemic, cold preservation, or reperfusion periods. TUNEL-positive SEC and caspase 3-like activity in the liver was increased by CI-WR. Three caspase inhibitors (IDN-8066, IDN-1965, and IDN-6556) effectively attenuated SEC apoptosis and caspase 3 activation. The most potent inhibitor, IDN-6556, reduced SEC apoptosis and caspase 3 activity by 55% and 94%, respectively. Prevention of SEC apoptosis by IDN-6556 was not reduced when this agent was administered only during the cold preservation period. When added to the preservation solution, the caspase inhibitor IDN-6556 appears to be a feasible therapeutic agent against ischemia-reperfusion injury in liver transplantation.