Comparison of hepatic artery and portal vein reperfusion during orthotopic liver transplantation.

BACKGROUND: During orthotopic liver transplantation (OLT), it is standard procedure to reperfuse the liver via the portal vein (PV) despite having a lower oxygen content and perfusion pressure than the hepatic artery (HA). There are no published studies that describe graft function and outcome when the HA is used for reperfusion. We report a retrospective comparison of graft outcome after HA or PV reperfusion when the piggyback technique was used. METHODS: We identified 26 patients who had undergone OLT with HA reperfusion and 26 patients reperfused via the PV. Demographics, primary diagnosis, surgeon, warm and cold ischemic times, and blood product use were recorded. In each patient, whole blood lactate concentration, prothrombin time (PT), and alanine aminotransferase (ALT) were measured at defined time points during and after surgery as indices of graft lactate metabolism, synthetic function, and reperfusion injury, respectively. Thirty-day and 1-year outcome data were recorded. Data were compared between the HA and PV groups. RESULTS: Demographics, blood product use, primary diagnosis, cold ischemic time, and surgeon were similar between the groups. Warm ischemic time was longer in the HA group (mean [SD] HA 51.2 [14.7], PV 40 [9.1] min, P=0.002). Blood lactate concentrations were similar at all time points. There was no difference in 24-hr postoperative PT between the groups (median [InterQuartile (IQ) range] HA 17.5 [16-28.3], PV 19 [16-24] sec, P=0.85). Peak postoperative ALT values were comparable (median [IQ range] HA 1031 [668-1701], PV 1107 [754-1824] IU/ml, P=0.78). There were no statistically significant differences in 30-day or 1-year mortality, but more early deaths occurred in the HA group. Using our data, we calculated that a prospective randomized trial would need approximately 300 patients to be sure that mortality was the same with both techniques. CONCLUSION: We have demonstrated no clinically or statistically significant differences in indices of graft function, reperfusion injury, or outcome between primary HA or PV reperfusion.     

缺血或药物预处理对大鼠供肝缺血再灌注损伤的抑制作用

目的　探讨缺血预处理 (IPC)或阿霉素预处理 (DPC ,模拟IPC)对大鼠供肝延迟性保护作用的发生机制。方法　将供鼠分为 3组。IPC组 :供鼠采用肝脏预先缺血 10min后再开放 ;DPC组 :供鼠经静脉注射阿霉素 (1mg/kg体重 ) ;对照组 :供鼠用等量生理盐水注射。观察各组预处理后血红素氧化酶 1(HO 1)和热休克蛋白 70 (HSP70 )含量 ;建立上述各组大鼠原位肝移植模型 ,并设假手术对照组 ,观察肝移植后各组对供肝缺血再灌注损伤的影响。结果　IPC组HO 1、HSP70含量分别于预处理 12h和 2 4h达到高峰 ;IPC和DPC组预处理 2 4h ,诱导的HSP70、HO 1含量差异无显著性 (P >0 .0 5 )。对照组肝移植后 6h ,肝组织中ICAM 1mRNA表达和内皮细胞ICAM 1分子表达明显增强 ,髓过氧化物酶 (MPO)活性增高 ,血清中天冬氨酸转氨酶 (AST)、丙氨酸转氨酶 (ALT)、乳酸脱氢酶 (LDH)及肝组织湿重 /干重 (W/D)水平明显升高 ,和假手术组相比 ,差异有显著性 (P <0 .0 1)。IPC或DPC组肝移植后减弱了ICAM 1mRNA和蛋白表达及MPO活性 ,AST、ALT、LDH及W/D的水平亦明显降低 ,与对照组比较 ,差异有显著性 (P <0 .0 5 )。结论　IPC的延迟保护作用是通过降低中性粒细胞的粘附浸润来实现的 ,这与IPC诱导生成HSP70和HO 1有关。DPC可以模拟IPC的延迟性保护     

热休克蛋白70和血红素加氧酶-1表达在肾缺血后处理减轻肾缺血再灌注损伤中的作用

目的 评价热休克蛋白70(HSP70)和血红素加氧酶-1(HO-1)表达在肾缺血后处理减轻肾缺血再灌注损伤中的作用.方法健康雄性SD大鼠140只,体重250～280 g,采用随机数字表法,将大鼠随机分为4组(n=35):假手术组(S组)仅开腹,游离双侧肾脏,分离双侧肾蒂不夹团;肾缺血再灌注组(I/R组)夹闭双侧肾蒂缺血45 min,恢复灌注;缺血后处理组(IPo组)夹闭双侧肾蒂45 min,再灌注10 s,缺血10 s,反复3次,恢复灌注;HSP抑制剂槲皮黄酮+缺血后处理组(Q+IPo组)缺血前1 h 腹腔注射槲皮黄酮100 mg/kg,余操作同IPo组.于再灌注即刻(T0)、1、3、6、12、24、48 h(T1～6)时各组随机取5只大鼠抽心脏血后取肾,检测肾组织HSP70、HO-1的mRNA和蛋白表达,T3时抽心脏血,测定血清肌酐(Cr)和尿素氮(BUN)浓度、caspase-3 mRNA的表达,TUNNEL法检测肾组织凋亡细胞,计算凋亡指数(AI),光镜下观察肾组织病理学结果.结果 与S组比较,其余组T3时血清Cr和BUN浓度和AJ升高,caspase-3 mRNA表达上调,各时点HSF70、BO-1的mRNA和蛋白表达上调(P＜0.05);与I/R组比较,IPo组T3时血清Cr和BUN浓度和AI降低,caspase-3 mRNA表达下调,T1～5时HSP70、HO-1的mRNA和蛋白表达上调(P＜0.05);与IPo组比较,Q+IPo组T3时血清Cr和BUN浓度和AJ升高,caspase-3mRNA表达上调,T1～5时HSP70、HO-1的mRNA和蛋白表达下调(P＜0.05).IPo组肾组织病理学损伤较I/R组减轻,Q+IPo组肾组织病理学损伤程度与I/R组相似.结论 HSP70和H0-1表达参与了肾缺血后处理减轻肾缺血再灌注损伤的过程.

Abstract：

Objective To evaluate the role of the expression of heat shock protein 70 (HSP70) and heme oxygenase-1 (HO-1) in the reduction of renal ischemia-reperfusion (I/R) injury by ischemic postconditioning in tats.Methods One hundred and forty healthy male SD rats weighing 250-280 g were randomized into 4 groups ( n = 35 each) : sham operation group (S group) ; I/R group; ischemic postconditioning group (IPo group); quercetin (an inhibitor of HSP) + ischemic postconditioning group (Q + IPo group). Renal I/R was produced by clamping bilateral renal pedicels for 45 min followed by reperfusion. In group S, bilateral kidneys were only exposed through a midline incision but their- pedicels were not clamped. In IPo and Q + IPo groups, 45 min ischemia was followed by three 10 s episodes of ischemia at 10 s intervals for reperfusion and in addition intraperitoneal quercetin 100 mg/kg was injected at 1 h before ischemia in group Q + IPo. Blood samples from hearts were obtained at 0, 1, 3, 6, 12, 24 and 48 h of reperfusion (T0-6) and the rats were then sacrificed and kidneys removed to detect the expression of HSP70 and HO-1 mRNA and protein in renal tissues. The blood samples obtained at T3 were used to determine serum creatinine (Cr) and urea nitrogen (BUN) concentrations and the expression of caspase-3 mRNA . The apoptosis in the renal tissues was detected using TUNEL and apoptotic index ( AI) was calculated. Microscopic examination was performed with light microscope. Results Compared with group S, the serum Cr and BUN concentrations and AI were significantly increased at T3,the expression of caspase-3 mRNA was up-regulated at T3, and the expression of HSP70 and HO-1 mRNA and protein was up-regulated at T0-6 in the other groups (P ＜ 0.05) . Compared with group I/R, the serum Cr and BUN concentrations and AI were significantly decreased at T3, the expression of caspase-3 mRNA was down-regulated at T3, and the expression of HSP70 and HO-1 mRNA and protein was up-regulated at T1-5 in group IPo ( P ＜ 0.05) . Compared with group IPo, the serum Cr and BUN concentrations and AI were significantly increased at T3, the expression of caspase-3 mRNA was up-regulated at T3, and the expression of HSP70 and HO-1 mRNA and protein was down-regulated at T1-5, in group Q + IPo ( P ＜ 0.05) . The microscopic examination showed that the renal I/R injury was significantly attenuated by ischemic postconditioning and the degree of injury in group IPo was similar to that in group I/R. Conclusion The expression of HSP70 and HO-1 is involved in the reduction of renal I/R injury by ischemic postconditioning in rats.     

Sequential versus contemporaneous portal and arterial reperfusion during liver transplantation

Although sequential portal and arterial revascularization (SPAr) is the most common method of graft reperfusion at liver transplantation (OLT), contemporaneous portal and hepatic artery revascularization (CPAr) has been used to reduce arterial ischemia to the bile ducts. The aim of this study was to prospectively compare SPAr (group 1; n = 19) versus CPAr (group 2; n = 21) among 40 consecutive OLT from heart-beating donors. There were no differences in the demographics characteristics, Model for End-stage Liver Disease scores, indication for OLT and donor parameters between the groups. OLT was performed using the piggyback technique. The biliary anastomosis was performed in all cases by a duct-to-duct technique with a T-tube in 32% versus 29% of cases without a T tube (P = .83). In the CPAr group, the liver was reperfused simultaneously via the portal vein and hepatic artery. CPAr showed a longer warm ischemia (66 ± 8 vs 37 ± 7 minutes; P < .001), while SPAr had a longer arterial ischemia 103 ± 42 vs 66 ± 8 minutes (P = .0004). Recovery of graft function was similar. There was no primary nonfunction and delayed graft function occurred among 10% versus 9%. Liver function tests were similar between the two groups up to 90 days case of follow-up- One-year graft and patient survivals were, respectively, 89% and 95% versus 94% and 100% (P = .29). At a median follow-up of 13 ± 6 versus 14 ± 7 months, biliary complications included anastomotic stenoses in 15% versus 19% (P = .78) and intrahepatic non-anastomotic biliary strictures in 26% versus none (P = .01) for SPAr and CPAr, respectively. CPAr was safe and feasible, reducing the incidence of intrahepatic biliary strictures by decreasing the duration of arterial ischemia to the intrahepatic bile ducts.     

Metabolic changes induced by ischemia and cardioplegia: a study employing cardiac microdialysis in pigs.

OBJECTIVE: The present study investigates dynamic changes of myocardial metabolism in response to ischemia, cardioplegia, and extracorporeal circulation (ECC) in order to differentiate between the contributing effects of each of these interventions. Furthermore, warm blood cardioplegia versus empty beating of the heart were compared as methods to resuscitate the ischemic myocardial metabolism. METHODS: Swedish Landrace pigs on ECC (ECC) were compared with pigs on ECC with warm ischemic cardiac arrest (ischemia) or on ECC with warm ischemic arrest followed by warm blood cardioplegia (ischemia-cardioplegia), using sham-operated pigs as controls (n=7 in each group). Microdialysis probes were placed on the surface of the left ventricle and in the femoral artery for serial evaluation of metabolites in the intracardiac extracellular fluid and arterial blood. When hearts started in ventricular fibrillation (VF), it was electroconverted after 10 min of normal blood reperfusion. If VF started after 10 min of reperfusion electroconversion was immediately performed. RESULTS: There were no differences between groups in arterial contents of serine, citrulline, arginine, inosine, hypoxanthine, guanosine, aspartate, glutamate, pyruvate, or asparagine throughout the observation period. Systemic lactate increased in pigs subjected to ischemia (P<0.001) or ischemia and cardioplegia (P=0.002), highest in the ischemia only group (P=0.002). In left ventricular microdialysates, lactate increased in pigs subjected to ischemia alone (P<0.001 vs. ECC) and ischemia and cardioplegia (P=0.004 vs. ECC). Guanosine increased in ischemia versus ECC (P=0.002), while hypoxanthine was increased in microdialysates of both ischemic (P=0.002) and ischemic-cardioplegic (P=0.001) pig hearts. Inosine was increased in pigs subjected to ischemia and cardioplegia (P<0.001 vs. ECC). All ischemic hearts started with VF, but while in the warm ischemia group VF started within 10 min of reperfusion, the ischemia-cardioplegia group had a longer asystolia with VF starting 11-22 min of blood reperfusion. CONCLUSION: The heart should be allowed to start empty beating rather than by the use of warm continuous blood cardioplegia. Microdialysis and sampling of interstitial metabolites may be advantageous when an increased sensitivity is needed or when repeated blood sampling is difficult or contraindicated in monitoring of the myocardium.     

Sequential and simultaneous revascularization in adult orthotopic piggyback liver transplantation.

The aim of the study was to assess whether there is a difference in outcome after sequential or simultaneous revascularization during orthotopic liver transplantation (OLT) in terms of patient and graft survival, mortality, morbidity, and liver function. The study population consisted of 102 adult patients with primary full-size piggyback OLT transplanted between January 1998 and December 2001. In 71 patients (70%) the grafts were sequentially reperfused after completion of the portal vein anastomosis and subsequent arterial reconstruction was performed (sequential reperfusion [SeqR] group). In 31 patients (30%) the graft was reperfused simultaneously via the portal vein and hepatic artery (simultaneous reperfusion [SimR] group). Patient and graft survival at 1, 3, and 6 months and at 1 year did not differ between the SeqR group and the SimR group. The red blood cell (RBC) requirements were significantly higher in the SimR group (5.5 units; range 0-20) in comparison to the SeqR group (2 units; range 0-19) (P = 0.02). Apart from a higher number of biliary anastomotic complications and abdominal bleeding complications in the SimR group in comparison to the SeqR group (13% vs. 2% and 19% vs. 6%, respectively; P = 0.06), morbidity was not different between the groups. No differences between the groups were observed regarding the incidence of primary nonfunction (PNF), intensive care unit stay, and acute rejection. This was also true for the severity of rejections. Postoperative recuperation of liver function was not different between the groups. In conclusion, no advantage of either of the 2 reperfusion protocols could be observed in this analysis, especially with respect to the incidence of ischemic type biliary lesions (ITBL).     

ROCK inhibitor Y-27632 prevents primary graft non-function caused by warm ischemia/reperfusion in rat liver transplantation

Hepatic stellate cells (HSCs) can easily be activated by ischemia/reperfusion, and this activation results in hepatic microcirculatory disturbance by cell contraction. ROCK is one of the key regulators of the motility of HSCs, and Y-27632 suppresses the activation of HSCs. We examined whether Y-27632 treatment prevents primary graft non-function caused by 45-min warm ischemia in orthotopic liver transplantation (OLT). Donor and recipient rats were administered Y-27632 (3-30 mg/kg). Y-27632 treatment at 30 mg/kg in both donor and recipient prevented congestion of the grafted livers, as demonstrated by analysis of hemoglobin (Hb) content in the grafted livers, using in-vivo near-infrared spectroscopy. Serum levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), and hyaluronic acid at 4 h after OLT in the 30-mg/kg Y-27632-treated group were significantly lower than those in the control group. Specimens from the untreated control recipients showed sinusoidal congestion and massive fresh hepatocyte necrosis, whereas specimens from the Y-27632-treated recipients demonstrated minimal histological changes. Moreover, Y-27632 pre-treatment dramatically improved the survival of recipients. These results suggest that Y-27632 would be clinically useful for preventing liver failure associated with ischemia/reperfusion in liver transplantation.     

Retrograde reperfusion via vena cava lowers the risk of initial nonfunction but increases the risk of ischemic-type biliary lesions in liver transplantation – a randomized clinical trial

Initial nonfunction (INF) and biliary complications such as ischemic-type biliary lesion (ITBL) remain two major complications in clinical orthotopic liver transplantation (OLT). The influence of ischemia and reperfusion injury (I/R) as a significant risk factor for both complications is widely unquestioned. A new reperfusion technique that reduces I/R injury should lead to a reduction in both INF and ITBL. One hundred and thirty two OLT patients were included in this study and randomized into two groups. Group A underwent standard reperfusion with anterograde simultaneous arterial and portal reperfusion and group B received retrograde reperfusion via the vena cava before sequential anterograde reperfusion of portal vein and hepatic artery. Serum transaminase level as a surrogate parameter for I/R injury and serum bilirubin level as a parameter for graft function were significantly reduced during the first week after OLT in group B. INF rate was 7.7% in group A and 0% in group B (P = 0.058). ITBL incidence was 4.55% in group A versus 12.3% in group B (P = 0.053). Retrograde reperfusion seemed to be beneficial for hepatocytes, but was detrimental for the biliary epithelium. The unexplained increased incidence of ITBL after retrograde reperfusion will be focus of further investigation.     

Experimental study of the effect of intraportal prostaglandin E1 on hepatic blood flow during reperfusion after ischaemia and hepatectomy.

BACKGROUND: Prostaglandin E1 (PGE1) has protective effects experimentally and clinically in individual models of hepatic ischaemia-reperfusion injury and of partial hepatectomy. The present study investigated the effects of intraportal administration of PGE1 on hepatic blood flow, systemic arterial pressure and long-term animal survival after 60 min of total liver ischaemia followed by 70 per cent partial hepatectomy in rats. METHODS: Total liver ischaemia was induced by occluding the hepatoduodenal ligament for 60 min. PGE1 0.5 microg per kg per min was infused intraportally for 15 min before inducing ischaemia and for 120 min after ischaemia in the treatment group. Normal saline was infused in the control group. During ischaemia 70 per cent partial hepatectomy was performed. Portal venous flow (PVF), peripheral tissue blood flow (PTBF) and hepatic artery flow were measured before and after ischaemia. Serum biochemical analysis was carried out at 1, 3 and 24 h, and 7 and 14 days; and liver histology at 1 and 24 h, and 7 days after reperfusion. Survival was followed for 1 year. RESULTS: Intraportal infusion of PGE1 significantly improved PVF and PTBF without affecting the systemic arterial pressure. Long-term survival was significantly higher in the PGE1 group. Serum aspartate aminotransferase, alanine aminotransferase and alkaline phosphatase levels decreased significantly, and 2-h bile flow was significantly improved, in the PGE1 group. Histological examination revealed significant portal venous congestion, sinusoidal congestion, fatty degeneration and tissue necrosis 24 h and 7 days after reperfusion in the control group. CONCLUSION: PGE1 has a protective effect against liver damage when the liver is injured by warm ischaemia and reperfusion followed by partial resection.     

肝移植术中再灌注前经门静脉放血对内环境和心肺功能的影响

目的 研究肝移植术中再灌注前放血的临床意义.方法 32例肝病患者在静脉及吸入复合全麻下行无转流原位肝移植术,分为再灌注前放血组(经门静脉放血200 ml,21例)和对照组(11例).常规麻醉监测,并放置Swan-Ganz导管监测心输出量,无肝前期、无肝期给予抑肽酶、去甲肾上腺素及多巴胺,维持无肝期平均动脉压＞70 mm Hg,心输出量指数＞2.5 L·min-1·m-2.分别于门静脉阻断即刻(T1)、门静脉开放即刻(T2)、新肝期10min(T3)、新肝期30min(T4)采集桡动脉血液测定电解质、血气及炎性细胞因子浓度(肿瘤坏死因子tumor necrosis factor alpha-alpha,TNF-α;白介素6,Interleukin-6,IL-6).各时间点分别记录心肺功能参数.结果 两组患者心律失常发生率(X2=1.73,P＞0.05)和死亡率(X2=1.12,P＞0.05)没有显著差别;各时间点血钙、血镁浓度均明显低于正常值;两组患者桡动脉血钾、TNF-α、IL-6均无显著变化,再灌注前放血对乳酸的增长没有影响;各时间点肺氧合功能、心功能参数无显著变化,组间无明显差异.新肝期30 min,两组患者均表现为乳酸、炎性因子呈增高趋势,外周血管阻力指数(systemic vascular resistance index,SVRI)显著下降.结论 再灌注前放血似乎对内环境、心肺功能影响较小.     

Hepatic stellate cell activation and hepatic fibrosis induced by ischemia/reperfusion injury

Objective

Warm ischemia causes severe allograft damage in liver transplantation. However, the long-term effects of ischemia/reperfusion injury (IRI) on fibrosis have not been fully elucidated. In this study, we used a partial warm hepatic ischemia mouse model to monitor fibrosis in the ischemic liver.

Materials and Methods

Male BALB/c mice were divided into ischemic and sham groups (n = 30/group). Via a midline laparotomy, an atraumatic clip was used to interrupt the arterial and the portal venous blood supply to the left liver lobe. After 90 minutes of partial hepatic ischemia, the clip was removed initiating hepatic reperfusion. Samples from normal, sham, and ischemic liver tissues were collected at intervals of 1, 5, 10, 15, 20, or 30 days after operation (n = 5 for each time point) for hematoxylin-eosin (H&E), Mallory's trichrome, and alpha-smooth muscle actin (α-SMA) immunohistochemical stains for fibrosis and activation of hepatic stellate cell (HSCs).

Results

IRI caused significant HSC activation in the ischemic liver tissues. Mallory's trichrome stain demonstrated that IRI caused hepatic parenchymal fibrosis near portal tracts and central veins. With prolonged reperfusion time hepatic parenchymal fibrosis was aggravated, showing the same pattern of HSC activation. IRI also caused increased portal tract fibrosis in ischemic liver tissues, especially around biliary tracts.

Conclusions

Hepatic IRI caused HSC activation, increasing hepatic parenchymal and portal tract fibrosis in ischemic liver tissues.     

Pharmacologic preconditioning effects: Prostaglandin E1 induces heat-shock proteins immediately after ischemia/reperfusion of the mouse liver

Prostaglandin E1 (PGE1) has several potential therapeutic effects, including cytoprotection, vasodilation, and inhibition of platelet aggregation. This study investigates the protective action of PGE1 against hepatic ischemia/reperfusion injury in vivo using a complementary DNA microarray. PGE1 or saline was continuously administered intravenously to mice in which the left lobe of the liver was made ischemic for 30 minutes and then reperfused. Livers were harvested 0, 10, and 30 minutes postreperfusion. Messenger RNA was extracted, and the samples were labeled with two different fluorescent dyes and hybridized to the RIKEN set of 18,816 full-length enriched mouse complementary DNA microarrays. Serum alanine aminotransferase and aspartate aminotransferase levels at 180 minutes postreperfusion were significantly lower in the PGE1-treated group than in the saline-treated group. The cDNA microarray analysis revealed that the genes encoding heat-shock protein (HSP) 70, glucose-regulated protein 78, HSP86, and glutathione S-transferase were upregulated at the end of the ischemic period (0 minutes postreperfusion) in the PGE1 group. Our results suggested that PGE1 induces HSPs immediately after ischemia reperfusion. HSPs might therefore play an important role in the protective effects of PGE1 against ischemia/reperfusion injury of the liver.     

Prior induction of heat shock proteins by a nitric oxide donor attenuates cardiac ischemia/reperfusion injury in the rat

BACKGROUND: Recent studies have demonstrated that nitric oxide (NO) releasers considerably increase heat shock proteins (HSPs) in the in vitro cell system, providing resistance to oxidant damage. This study was designed to examine the cellular responses of HSPs induced by prior administration of an NO releaser, FK409 (FK), in an in vivo transplantation model. METHODS: Lewis rats received either saline or FK solution intravenously administered at different time points before graft harvesting (10 micromol/kg) or for 15 min during reperfusion (0.66 micromol/kg/min). Tissue specimens were taken to determine HSP70 and heme oxygenase-1/HSP32 (HO-1) expression, and glutathione content. After 24-hr preservation with University of Wisconsin solution, heterotopic cardiac transplantations were performed, and graft survival was determined at 14 days. Tissue samples for end labeling of nuclear DNA fragments (TdT-mediated d-uridine triphosphate biotin nick end labeling; TUNEL) and propidium iodide staining were taken 15 min after reperfusion. RESULTS: The gene and protein expression of HSP70 after FK administration peaked at 12 min and 60-90 min, whereas those of HO-1 peaked at 6 min and 90 min, respectively. Then, representative cardiac grafts taken 60 min after FK treatment were examined for further assay. Localization of induced HSP70 and HO-1 molecules were observed in the myocardium and vascular endothelium, respectively. Prior treatment of FK was effective in preventing the reduction of tissue glutathione contents compared with control (P<0.05). Fewer TUNEL and propidium iodide-positive cells were also observed in the FK group (P<0.0005, vs. control). The graft survival rate was higher in the FK group (9/10 vs. 1/10 of control; P<0.001), whereas the groups either harvested 10 min after FK pretreatment or continuously infused for 15 min during reperfusion were inferior, similar to that of control. CONCLUSION: Prior induction of HSP70 and HO-1 with a relatively low dose of FK administration attenuates ischemia and reperfusion injury, which was due to antioxidant and antiapoptotic activities augmented by such stress proteins. Thus, NO releasers as a pharmacological maneuver may provide an innovative approach for the prevention of ischemia and reperfusion injury.     

An adenosine A2A agonist, ATL-146e, reduces paralysis and apoptosis during rabbit spinal cord reperfusion

BACKGROUND: We hypothesized that systemic ATL-146e, an adenosine A(2A) agonist, would decrease spinal cord reperfusion inflammatory stress and inhibit apoptosis and that these effects would correlate with improved neurologic functional outcome. METHODS: Thirty rabbits underwent cross-clamping of the infrarenal aorta for 45 minutes. One group of animals (n = 14) received 0.06 microg/kg per minute of ATL-146e infused intravenously for 3 hours, beginning 15 minutes before reperfusion. A second group of animals (n = 16) underwent spinal cord ischemia with saline vehicle alone and served as ischemic controls. Animals (n = 9, 11) from each group survived for 48 hours and assessed for neurologic impairment with the Tarlov (0-5) scoring system. Four animals from each group were humanely killed at the end of the 3-hour treatment period, and the remainder killed after 48 hours' survival. In all animals, lumbar spinal cord tissue specimens were frozen for subsequent Western blot analysis of heat shock protein 70 (HSP 70), and for the p85 fragment of poly (ADP-ribose) polymerase (PARP). Neuronal viability indices were determined at 48 hours with hematoxylin and eosin staining. RESULTS: There was improvement in neurologic function in rabbits receiving ATL-146e (P <.001) compared with ischemic controls. At the end of the 3-hour treatment period there was a 46% (P <.05) decrease in HSP 70 expression in the ATL-146e group compared with the control group, but no difference in PARP expression. At 48 hours, there was no difference between control and ATL-146e groups in HSP 70 expression, but there was a 65% (P <.05) reduction in PARP in the spinal cords of animals that had received ATL-146e. There was a significant improvement in neuronal viability indices in animals receiving ATL-146e compared with ischemic controls (P <.05). CONCLUSIONS: Systemic ATL-146e infusion during reperfusion after spinal cord ischemia results in preservation of hindlimb motor function. There is evidence of decreased spinal cord inflammatory stress immediately after treatment with ATL-146e as indicated by reduced HSP 70 induction. Treatment with ATL-146e is associated with a reduction in neuronal apoptosis as suggested by a substantial decrease in the fragmentation of PARP at 48 hours. These results suggest that inflammation during reperfusion and subsequent apoptosis contribute to paralysis after restoration of blood flow to the ischemic spinal cord.     

Portacaval shunt and inferior vena cava preservation in orthotopic liver transplantation

The aim was to study the advantages of the use of a temporary portacaval shunt (PCS) with inferior vena cava (IVC) preservation during the piggyback technique for the anhepatic phase of orthotopic liver transplantation (OLT) performed in cirrhotic patients. Two groups of cirrhotic patients who underwent OLT with piggyback technique were compared; one with a PCS (n = 57) and the other, without PCS (n = 54). Patients with fulminant hepatitis, retransplantation, portal thrombosis, and previous portosystemic shunts were excluded. In both groups graft reperfusion was achieved by simultaneous arterial and venous revascularization. Donor, recipient, and surgical characteristics were similar in both groups. The PCS group had a significantly higher portal venous flow (PVF) than the no-PCS group (773 +/- 402 mL/min vs 555 +/- 379 mL/min, P = .004). Therefore, two subgroups were studied; the high PVF subgroup A (>800 mL/min), mean 1099 +/- 261 mL/min, and the low PVF subgroup B (<800 mL/min), mean 433 +/- 423 mL/min. Subgroup A, who were treated with PCS, required fewer blood transfusions and displayed better postoperative renal function; whereas, no differences were observed among subgroup B patients with versus without PCS. In conclusion, the use of a temporary PCS with piggyback technique during OLT in cirrhotics has advantages in patients who still maintain a high portal venous flow.     

临时性腔门静脉半转位术在门静脉栓塞患者肝移植术中作用

摘要：目的:探讨临时性腔门静脉半转位术(TCPHT)在门静脉栓塞(PVT)患者经典非转流肝移植(OLT)中的应用价值。 方法:总结5年间32例肝移植术前合并Yerdel Ⅲ~Ⅳ级PVT患者中11例施行TCPHT术（TCPHT组）、21例未施行TCPHT术(对照组)者的临床资料。比较两组患者的手术时间和无肝期时间、再灌注期平均动脉压（MAP）、中心静脉压（CVP）和肺动脉楔压（PAWP）等循环参数以及无肝期尿量、再灌注期尿量等肾功能参数。结果:TCPHT组和对照组手术时间和无肝期时间均无显著性差异（P>0.05）。两组比较，虽然术后第1天肾功能指标差异无显著性，但TCPHT组无肝期尿量明显增加，两者分别为（64.09±20.79）mL和（25.90±12.17）mL （P=0.033)；再灌注期尿量分别是(1254.56±311.81) mL和（800.00±375.83）mL,（P=0.002)，且TCPHT组术后需要透析的病例数较对照组显著减少(P<0.05)。体循环血流动力学显示，TCPHT组较对照组开放后具有更加稳定的MAP，两组分别为(76.45±12.67)mmHg和（66.52±7.48）mmHg（P=0.032)；CVP分别为（13.96±1.74）cm H2O和（12.44±1.07）cm H2O （P=0.005)；PAWP分别为（24.04±1.48）mmHg和（22.81±1.23）mmHg （P=0.018)。结论:TCPHT能有效地稳定门静脉栓塞患者肝移植再灌注期血流动力学，减少术后肾功能不全的发生率，而不增加手术难度。     

Effect of early arterialization of the porcine liver allograft on reperfusion injury,hepatocellular injury,and endothelial cell dysfunction

The conventional technique of liver transplantation involves the initial perfusion of the graft with portal blood. However, recent evidence suggests that initial arterialization of the graft may be better. The aim of this study is to evaluate the timing of arterialization on reperfusion injury, hepatocellular injury, and endothelial cell function after liver transplantation. Large white X Landrace pigs (n = 24) were subjected to orthotopic liver transplantation. The animals were randomly assigned to 4 groups, ranging from late arterialization (60 minutes after portal reperfusion) to early rearterialization (20 minutes before portal reperfusion). Aspartate aminotransferase levels continued to increase 4 hours posttransplantation in group 1 (late arterialization), but remained stable after 1 hour posttransplantation in group 4 (early rearterialization). Levels of malondialdehyde doubled in all groups after portal reperfusion with the exception of group 4, in which the liver received arterial blood before portal reperfusion. Vitamin A levels decreased in all groups after revascularization, but the decrease was more pronounced and prolonged in groups 1 and 2 (late arterialization) compared with groups 3 and 4 (early rearterialization). Hyaluronic acid levels continued to increase in all groups until 1 hour posttransplantation except in group 4, in which the level decreased from 20 minutes posttransplantation. Results of this study show that early rearterialization is associated with less hepatocellular damage, less reperfusion injury, and improved liver endothelial cell function. In conclusion, our results indicate that early rearterialization of the graft is beneficial to the transplanted liver. (Liver Transpl 2001;7:32-37.)     

Ergothioneine pretreatment protects the liver from ischemia-reperfusion injury caused by increasing hepatic heat shock protein 70

BACKGROUND: Reperfusion of the liver after ischemia induces the expression of the heat shock genes and the synthesis of the heat shock proteins (HSP). We studied the effects of the natural antioxidant ergothioneine (EGT) treatment on the expression of HSP70 in ischemic-reperfused (IR) liver. METHODS: Adult male Wistar rats were randomly divided into three groups: Sham group given standard laboratory chow and water for 3 weeks followed by sham operation; Control group given standard laboratory chow and water for 3 weeks followed by liver IR injury; EGT group given standard laboratory chow supplementation l-ergothioneine (1.2 mg/kg/d body weight) administered by gavage and water for 3 weeks followed by liver IR injury. Ten rats from each group were killed to determine serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactic dehydrogenase (LDH), tissue malondialdehyde (MDA), HSP70 levels, and histologic changes at 30, 60, and 120 min of reperfusion, respectively. Survival was followed for 1 week. RESULTS: IR caused significant increase in serum AST, ALT, LDH, and tissue MDA levels. As compared with the control group, animals treated with EGT experienced a significant decrease in serum AST, ALT, and LDH levels in all reperfusion periods. Tissue MDA levels in animals receiving EGT were significantly reduced as compared with control group at 30 min and 60 min after reperfusion. After ischemia, reperfusion caused a remarkable production of HSP70 in the control group. When the rats were pretreated with EGT, the levels of HSP70 increased significantly in their livers after reperfusion compared with the control group. Liver injury in the EGT-treated animals was lower to that in the control group. The 7-day survival rate was significantly improved (from 50% to 80%) by EGT pretreatment. CONCLUSION: HSP70 has been shown to induce tolerance against warm IR injury in rat livers. EGT pretreatment protects the liver from IR injury by over-expression of HSP and the subsequent suppression of lipid peroxidation.     

Heat-shock preconditioning protects fatty livers in genetically obese Zucker rats from microvascular perfusion failure after ischemia reperfusion

Reduced tolerance of steatotic livers to ischemic injury is considered to correlate with impaired microcirculation. The aim of this study was to investigate the impact of heat-shock preconditioning (HSPC) on microcirculatory failure after ischemia/reperfusion (I/R) in steatotic livers by means of intra-vital fluorescence microscopy. Obese Zucker rats were used. In the HS group, rats underwent whole-body hyperthermia followed by 60-min partial liver ischemia. In group IR, rats were exposed only to ischemia. Microcirculation parameters (sinusoidal perfusion rate, sinusoidal diameter, leukocyte-endothelial interaction) were significantly better preserved in the HS group than in the IR group. Liver enzymes, oxygenated glutathione/reduced glutathione (GSSG/GSH) ratio, and electron microscopy showed less damage in the HS group. A marked expression of heat shock protein 72 (HSP72) and heme oxygenase (HO-1) was found only in the livers of group HS. HSPC mitigated the I/R injury of steatotic livers by preventing post-ischemic failure of microcirculation. This beneficial effect was found to be associated with the induction of HSP72 and HO-1.