改良大鼠离体肝脏灌注模型在供肝冷保存中的应用研究

背景:供肝冷保存和缺血再灌注损伤是影响肝移植患者预后的关键因素,建立稳定的冷保存再灌注动物模型是开展相关研究的基础。目的:建立适用于综合评价供肝质量的改良大鼠离体肝脏灌注模型,为供肝冷保存研究提供合适的离体再灌注模型。方法:12只Sprague-Dawley大鼠随机分为两组,对照组正常获取供肝后进行离体灌注90 min,实验组供肝经30 min热缺血后获取,冷保存24 h后再行离体灌注。离体灌注期间监测灌注液转氨酶水平、电解质浓度和pH值;以压力感受器监测供肝门静脉压力;以超微自由基探针监测肝组织过氧化氢(HPO)水平。灌注结束后记录胆汁流出量,检测供肝组织丙二醛(MDA)、超氧化物歧化酶(Cu/Zn SOD)水平及其组织病理学改变和肝细胞凋亡情况。结果:与对照组相比,实验组供肝AST、ALT水平、门静脉压力和HPO水平明显增高,胆汁流出量显著减少,肝组织Cu/Zn SOD水平显著降低。对照组供肝组织病理学损伤和肝细胞凋亡相对较轻。结论:经热缺血和冷保存后,供肝的肝功能和抗氧化能力均明显降低。本研究构建的改良大鼠离体肝脏灌注模型可有效监控和评估大鼠供肝冷保存再灌注损伤情况。     

供肝灌洗液中TNF-α水平与供肝质量关系的实验研究

目的探讨大鼠供肝冷保存过程中腔静脉灌洗液中肿瘤坏死因子(TNF-α)水平随时间的变化及其与供肝质量的关系。方法建立大鼠肝移植的供肝切取的动物模型,切取供肝后0℃~4℃冷保存。将实验动物分为7组,每组动物6只,分别在0、4、8、12、16、20、24小时取冷保存时腔静脉灌洗液标本1ml,测肝功能和TNF-α浓度。供肝做石蜡切片病理检查。结果在热缺血时间相同的情况下,大鼠供肝腔静脉灌洗液中肝功能水平和TNF-α水平随冷保存时间延长而增加。大鼠供肝腔静脉灌洗液中TNF-α水平与供肝质量相关。结论肿瘤坏死因子在肝脏缺血再灌注损伤中起重要作用,是介导损伤机制的重要细胞因子之一,其有作为评价供肝质量的一种指标的潜在价值。     

大鼠肝缺血再灌注损伤致心肌细胞凋亡的研究

肝移植术中病肝切除和供肝血流恢复有时存在着缺血再灌注损伤。肝脏缺血再灌注损伤过程中肝脏及肝外器官会出现一系列功能、代谢和结构的损伤,肝脏缺血后再恢复血流,血液从肝静脉回到右心房,心脏为接受肝缺血再通后血液的第一站。因此探索肝缺血再灌注损伤是否并发心脏的损伤及其可能的机制,以寻找减少损伤、增加机体抗损伤的方法是一项亟待解决的课题。本研究旨在观察肝缺血再灌注损伤时iNOs、c-fos在心肌组织中的表达和心肌细胞凋亡的关系以及可能的机制。     

供移植肝脏保存液及肝细胞保护剂研究进展

安全有效的器官保存是器官移植成功的先决条件 ,器官保存的目的就在于使离体缺血的器官保持最大活力 ,并于移植后迅速恢复器官功能。迄今为止 ,供移植肝低温保存仍是普遍采用的方法 ,但肝低温保存再灌注损伤是导致肝移植术后原发性无功能(Primarygraftnon -functionPGF)等早期并发症发生的重要因素 ,也是肝移植的难题之一。近年来 ,在改进肝脏保存液的成份方面进行了大量研究 ,并取得进展。本文就肝脏保存液及肝细胞保护剂方面研究近况作一概述。1　目前常用的肝脏灌注液和保存液1 1　仿细胞外液型液 :组成成份接近细胞外液 ,最初配制为简…     

自噬在肝脏缺血再灌注损伤中的作用及研究进展

肝脏缺血再灌注损伤是肝脏外科常见的一种并发症,是导致术后肝功能障碍的重要原因.肝脏缺血再灌注损伤的发生机制十分复杂,涉及多种因素.自噬是真核细胞内的一种溶酶体依赖的降解途径,具有维持细胞内环境稳定的作用.自噬在肝脏缺血再灌注损伤的发生发展过程中发挥重要的作用,是目前的研究热点之一,但是其具体作用及机制仍有较大争议.本文就自噬在肝脏缺血再灌注损伤中的作用及其机制作一详尽综述.     

肝窦内皮细胞在肝脏缺血再灌注损伤中的作用

肝脏缺血再灌注损伤是肝移植术后供肝原发性无功能的主要原因,而肝窦内皮细胞由于其所处的特殊解剖位置和生理特点,在缺血再灌注损伤的病理生理过程中发挥着重要作用。本文从再灌注后活性氧的产生、白细胞的粘附迁移、血管活性因子的释放等方面阐述肝窦内皮细胞在肝脏缺血再灌注损伤中的作用,并对如何防治展开初步探讨。     

促肝细胞生长素对肝细胞凋亡的影响

缺血再灌注是肝脏疾病中常见的临床病理过程 ,如肝脏手术、肝脏移植及失血性休克的输血抢救等 ,均存在肝组织缺血再灌注损伤。随缺血再灌注损伤时间及程度不同 ,既可出现可逆性损伤 ,也可出现不可逆性损伤。最近的研究表明 ,在肝缺血再灌注损伤中有肝细胞凋亡存在 ,这是一种不可逆性损伤[1] 。因此 ,在缺血再灌注过程中如何保护肝脏 ,减少不可逆损伤 ,提高肝脏对缺血再灌注损伤的耐受性 ,具有很重要的意义。材料和方法一、实验动物及缺血再灌注模型的制备Ｗｉｓｔａｒ大鼠 (黑龙江省肿瘤研究所提供 ) 5 0只 ,雌雄各半 ,重 2 0 0～ 2 5 0 ｇ…     

Nrf2及其信号通路在肝缺血再灌注损伤中作用的研究进展

肝缺血再灌注损伤是临床上常见的一种肝脏损伤类型.核因子红细胞2相关因子2(Nrf2)可以通过抑制氧化应激、抗炎、抑制细胞凋亡等多种作用来减轻肝脏缺血再灌注损伤.在肝缺血再灌注损伤中起作用的Nrf2相关信号通路主要有KEAP-Nrf2-ARE通路、DOR-PKC-Nrf2通路、Sirt1-Nrf2信号通路、PI3K-AK...     

肝脏缺血再灌注损伤的研究进展

肝部分切除是广泛运用于治疗肝脏良恶性肿瘤、肝内胆管结石、肝外伤等疾病,肝移植是治疗终末期肝病的唯一有效方式,但缺血再灌注损伤是肝切除术及肝移植的主要制约因素之一,其病理生理过程复杂,如何有效减轻术中缺血再灌注损伤将有助于降低手术对肝脏功能的影响.本文就缺血再灌注损伤分期、发生机制、对肝脏的不良影响及预防措施的相关研究作一综述.     

p38信号转导途径对离体肝脏缺血再灌注损伤的影响

目的 研究离体肝脏缺血再灌注期间p38信号转导途径的激活对其损伤程度的影响。 方法 通过自行建立的兔离体肝脏缺血再灌注模型,将一定剂量的特异性p38丝裂原激活蛋白激酶(MAPK)抑制剂SB202190加入到保存液中,根据原位灌注液及保存液中加入SB202190的剂量再将离体肝分为A、B、C、D4组。分别于冷保存前、冷保存末及再灌注5、10、15、30、60、120 min获取离体肝组织及受体兔静脉血液标本。分别应用免疫印迹杂交和免疫沉淀法测定离体肝组织磷酸化p38M A P K的活性。用全自动生化分析仪测定离体兔肝功酶学含量;并测定再灌注120 min内的胆汁分泌总量。 结果 在正常肝组织中p38 MAPK即有一定的基础活性;经冷保存后有一定的升高,再灌注10 min时达到峰值,然后逐渐下降,至再灌注120 min时降低至正常水平,而在冷保存液中加入SB202190后,再灌注期间p38 MAPK的活性受到显著性抑制,其中B、C、D组p38 MAPK活性峰值仅分别为A组的53.9％,12.8％,9.6％;再灌注期间各组受体肝酶学水平均表现为A>B>C>D,而胆汁分泌量表现为A相似文献   

Polyethylene glycols: An effective strategy for limiting liver ischemia reperfusion injury

Liver ischemia-reperfusion injury(IRI) is an inherent feature of liver surgery and liver transplantation in which damage to a hypoxic organ(ischemia) is exacerbated following the return of oxygen delivery(reperfusion). IRI is a major cause of primary nonfunction after transplantation and may lead to graft rejection, regardless of immunological considerations. The immediate response involves the disruption of cellular mitochondrial oxidative phosphorylation and the accumulation of metabolic intermediates during the ischemic period, and oxidative stress during blood flow restoration. Moreover, a complex cascade of inflammatory mediators is generated during reperfusion, contributing to the extension of the damage and finally to organ failure. A variety of pharmacological interventions(antioxidants, anticytokines, etc.) have been proposed to alleviate graft injury but their usefulness is limited by the local and specific action of the drugs and by their potential undesirable toxic effects. Polyethylene glycols(PEGs), which are non-toxic water-soluble compounds approved by the FDA, have been widely used as a vehicle or a base in food, cosmetics and pharmaceuticals, and also as adjuvants for ameliorating drug pharmacokinetics. Some PEGs are also currently used as additives in organ preservation solutions prior to transplantation in order to limit the damage associated with cold ischemia reperfusion. More recently, the administration of PEGs of different molecular weights by intravenous injection has emerged as a new therapeutic tool to protect liver grafts from IRI. In this review, we summarize the current knowledge concerning the use of PEGs as a useful target for limiting liver IRI.     

New strategies to optimize kidney recovery and preservation in transplantation

Optimizing kidney preservation is a primary issue in transplantation, particularly in relation to new donor sources, such as expanded criteria donors (ECDs) and donation after cardiac death (DCD). Kidneys from these donors are highly sensitive to ischemia-reperfusion injuries--the emblematic lesions encountered during transplantation. Despite years of research, static cold storage, with solutions designed in the 1980s, remains the gold standard in kidney transplantation. This kind of preservation, however, is unable to fully protect an ECD or DCD kidney, highlighting the need for novel strategies to improve kidney preservation or promote kidney recovery. This Review provides an overview of the emerging strategies to prevent ischemia-reperfusion injuries in donor kidneys and describes strategies that are aimed at the donor, organ or recipient to improve graft outcome. These approaches include management of donors, preconditioning of the kidney, improvements in organ preservation solutions, postconditioning and regenerative therapies of the kidney graft following transplantation. In addition, machine perfusion provides an interesting opportunity to evaluate kidney graft quality before transplantation. Overall, a combination of therapeutic approaches seem to provide the best outcome, but preclinical studies using relevant models are needed before these approaches can be incorporated into clinical practice.     

Protective effect of nitric oxide induced by ischemic preconditioning on reperfusion injury of rat liver graft

AIM: Ischemic preconditioning (IP) is a brief ischemic episode, which confers a state of protection against the subsequent long-term ischemia-reperfusion injuries. However, little is known regarding the use of IP before the sustained cold storage and liver transplantation. The present study was designed to evaluate the protective effect of IP on the long-term preservation of liver graft and the prolonged anhepatic-phase injury. METHODS: Male Sprague-Dawley rats were used as donors and recipients of orthotopic liver transplantation. All livers underwent 10 min of ischemia followed by 10 min of reperfusion before harvest. Rat liver transplantation was performed with the portal vein clamped for 25 min. Tolerance of transplanted liver to the reperfusion injury and liver damage were investigated. The changes in adenosine concentration in hepatic tissue and those of nitric oxide (NO) and tumor necrosis factor (TNF) in serum were also assessed. RESULTS: Recipients with IP significantly improved their one-week survival rate and liver function, they had increased levels of circulating NO and hepatic adenosine, and a reduced level of serum TNF, as compared to controls. Histological changes indicating hepatic injuries appeared improved in the IP group compared with those in control group. The protective effect of IP was also obtained by administration of adenosine, while blockage of the NO pathway using Nomega-nitro-L-arginine methyl ester abolished the protective effect of IP. CONCLUSION: IP appears to have a protective effect on the long-term preservation of liver graft and the prolonged anhepatic-phase injuries. NO may be involved in this process.     

Hypoxia inducible factor-1�� accumulation in steatotic liver preservation: Role of nitric oxide

AIM:To examine the relevance of hypoxia inducible factor(HIF-1)and nitric oxide(NO)on the preservation of fatty liver against cold ischemia-reperfusion injury(IRI). METHODS:We used an isolated perfused rat liver model and we evaluated HIF-1αin steatotic and non-steatotic livers preserved for 24 h at 4℃in University of Wisconsin and IGL-1 solutions,and then subjected to 2 h of normothermic reperfusion.After normoxic reperfusion,liver enzymes,bile production,bromosulfophthalein clearance,as well as HIF-1αand ...     

Impact of Celsior solution on hepatocellular, reperfusion and endothelial cell injury after liver transplantation

BACKGROUND: Initially, preservation solutions were developed to maintain cell function of the transplanted organs. However, recently developed preservation solutions also contain a variety of substances to reduce the reperfusion injury. AIM: To study the effect of three different preservation solutions on the liver cell injury, endothelial cell function and reperfusion injury after liver transplantation. MATERIAL AND METHODS: Large White X Landrace pigs of either sex were subjected to orthotopic liver transplantation. Donor livers were flushed and stored in University of Wisconsin Solution, Eurocollins Solution or Celsior Solution for 3 hours. Blood samples were taken at various times post transplantation for assessment of aspartate aminotransferase, hyaluronic acid, malondialdehyde and Vitamin A levels. RESULTS: Serum aspartate aminotransferase levels were lower in the livers preserved in the Wisconsin solution. Plasma malondialdehyde levels were lower and serum Vitamin A levels were higher in the livers preserved in Celsior solution. Serum hyaluronic acid levels increased after liver transplantation but were similar with all three solutions. CONCLUSIONS: There was less hepato-cellular injury in the livers preserved in Wisconsin solution and less reperfusion injury with the Celsior solution. The endothelial cell injury was similar with all three solutions.     

New preservation strategies for preventing liver grafts against cold ischemia reperfusion injury

BACKGROUND: In spite of improvements in University of Wisconsin (UW) preservation solution, the injury from grafts during cold storage is an unresolved problem in liver transplantation. The aim of the present study was to evaluate the beneficial effect on ischemia-reperfusion injury associated with liver transplantation of the inversion of K(+) and Na(+) concentrations and the replacement of hydroxyethyl starch (HES) by polyethylene glycol (PEG) in UW preservation solution. METHODS: Using an orthotopic liver transplantation model, the effects on rat liver preservation of a modified preservation solution (UW-PEG) were evaluated, based on the inversion of K(+) and Na(+) concentration and the replacement of HES by PEG 35 kDa (0.03 mmol/L) in UW preservation solution. RESULTS: The use of UW-PEG preservation solution ameliorated the biochemical and histological parameters of hepatic damage. Thus, at 24 h after transplantation, transaminase levels were reduced significantly when livers were preserved during 8 h in UW-PEG preservation solution compared with the original UW solution. In addition, histological findings revealed fewer and smaller areas of hepatocyte necrosis. The benefits of UW-PEG solution cannot be explained by modifications in oxidative stress or neutrophil accumulation associated with liver transplantation. However, the results of hepatic and portal blood flow indicated that the benefits of this modified preservation solution, UW-PEG were associated with improvements in the microcirculatory disorders after reperfusion. CONCLUSIONS: The UW-PEG solution, while retaining all the advantages of UW solution, improved hepatic ischemia-reperfusion injury associated with liver transplantation.     

Cold-preservation-induced sensitivity of rat hepatocyte function to rewarming injury and its prevention by short-term reperfusion

With increasing time of cold preservation, levels of high-energy nucleotides in the liver are reducing. The authors hypothesized that cold preservation sensitizes hepatocyte function to ischemic injury occurring during graft rewarming and that the injury can be prevented by short-term reperfusion. Rat livers were cold-preserved in University of Wisconsin solution for 0 to 18 hours and ischemically rewarmed for 0 to 45 minutes to simulate the implantation stage of transplantation. Hepatobiliary function was assessed using a blood-free perfusion model. In comparison with controls, neither 18-hour preservation nor 45-minute ischemic rewarming significantly influenced hepatocyte function. Compared with livers subjected to 45-minute ischemic rewarming, livers subjected to 9-hour preservation and 45-minute rewarming, and livers subjected to 18-hour preservation and 45-minute rewarming exhibited, respectively: 3.8 and 24 times reduced bile production, 4.3- and 116-fold decreased taurocholate excretion, and 3.1 and 42 times depressed bromosulfophthalein excretion. Thirty-minute oxygenated warm reperfusion after 9- and 18-hour preservation nearly completely blunted sensitization of hepatocyte function to rewarming ischemia. The authors found that short-term oxygenated reperfusion restored adenine nucleotides in liver tissue to the values found before organ preservation and that reperfusion with energy substrate containing solutions increased tissue adenosine triphosphate concentration to a higher level than that found before preservation. In conclusion, sensitization of hepatocyte function to rewarming ischemia increases disproportionally with storage time, suggesting that this phenomenon may play a role in graft dysfunctions with increasing liver preservation time. Short-term oxygenated reperfusion of the liver may protect hepatocyte functions against warm ischemic insult, even after extended preservation.     

Polyethylene glycol rinse solution:An effective way to prevent ischemia-reperfusion injury

AIM:To test whether a new rinse solution containing polyethylene glycol 35(PEG-35)could prevent ischemia-reperfusion injury(IRI)in liver grafts.METHODS:Sprague-Dawley rat livers were stored in University of Wisconsin preservation solution and then washed with different rinse solutions(Ringer’s lactate solution and a new rinse solution enriched with PEG-35 at either 1 or 5 g/L)before ex vivo perfusion with Krebs-Heinseleit buffer solution.We assessed the following:liver injury(transaminase levels),mitochondrial damage(glutamate dehydrogenase activity),liver function(bile output and vascular resistance),oxidative stress(malondialdehyde),nitric oxide,liver autophagy(Beclin-1 and LCB3)and cytoskeleton integrity(filament and globular actin fraction);as well as levels of metalloproteinases(MMP2 and MMP9),adenosine monophosphate-activated protein kinase(AMPK),heat shock protein 70(HSP70)and heme oxygenase 1(HO-1).RESULTS:When we used the PEG-35 rinse solution,reduced hepatic injury and improved liver function were noted after reperfusion.The PEG-35 rinse solution prevented oxidative stress,mitochondrial damage,and liver autophagy.Further,it increased the expression of cytoprotective heat shock proteins such as HO-1 and HSP70,activated AMPK,and contributed to the restoration of cytoskeleton integrity after IRI.CONCLUSION:Using the rinse solution containing PEG-35 was effective for decreasing liver graft vulnerability to IRI.     

Liver graft preservation:an overview

Liver graft preservationT he viability of the organ and its maintenance are very important during any transplant procedure and there is usually a period between the stoppage of the circulation in the donor and re-vascularisation of the organ in the recipient. During this period the harvested organ may have an irreversible harmful series of events rendering it not suitable for transplantation. This non-reversible damage which occurs during the ischaemic period depends partly on the metabolic re…     

Cold liver ischemia-reperfusion injury critically depends on liver T cells and is improved by donor pretreatment with interleukin 10 in mice

Kupffer cells are thought to mediate most of the deleterious effects of liver ischemia-reperfusion injury. The role of liver T cells and the impact of resident cell deactivation by interleukin 10 (IL-10) have never been addressed. Using a model of ex vivo liver cold ischemia and reperfusion, we assessed liver injury, tumor necrosis factor (TNF) and interferon gamma (IFN-gamma) release from livers of balb/c mice, nude mice, nude mice reconstituted with T cells, and gadolinium balb/c pretreated mice. The anti-inflammatory cytokine IL-10 was then used to define the best strategy of administration potentially able to modulate ischemia-reperfusion injury. For this purpose IL-10 was administered to the donor before liver harvesting, in the preservation medium during cold ischemia or during reperfusion. TNF and IFN-gamma were released time dependently and paralleled liver injury after reperfusion of cold preserved livers. Reperfused livers from nude or gadolinium pretreated mice disclosed a dramatic decrease in TNF and IFN-gamma release. Tissue injury was reduced by 51% in the absence of T cells and by 88% when Kupffer cells were deactivated. This effect was reverted by T-cell transfer to nude mice. Only donor pretreatment with IL-10 or IL-10 infusion during reperfusion led to a significant decrease in liver injury, TNF, and IFN-gamma release (-66% or -41%, -95% or -94%, and -70% or -70%, respectively). In conclusion, liver resident T cells are critically involved in cold ischemia-reperfusion injury and pretreatment of the donor with IL-10 decreases liver injury and the release of T-cell- and macrophage-dependent cytokines.