奥美拉唑对大鼠减体积肝移植后肝再生的影响

目的观察奥美拉唑对大鼠减体积肝移植肝细胞再生的影响。方法建立大鼠减体积肝移植模型，实验组移植后即时给予奥美拉唑，对照组予生理盐水。两组分别于肝移植术后分为5组（n=8），观察术后3、5、7、10、14d血清丙氨酸转氨酶、天冬氨酸转氨酶值、移植肝重／供肝减体积前全肝重比值、移植肝细胞有丝分裂指数（MI）、增殖细胞核抗原（PCNA）表达指数、溴脱氧尿嘧啶核苷（BrdU）掺入指数及血清胃泌素值。结果大鼠减体积肝移植术后5d肝细胞再生达高峰，实验组的再生活性显著高于对照组，MI为（2．54±0．24）％和（1．71±0．16）％（P〈0．01）、PC—NA指数为（26．96±2．09）％和（18．73±1．94）％（P〈0．01）、BrdU指数为（10．24±1．11）％和（5．75±0．88）％（P〈0．01）。术后7d，实验组和对照组移植肝重／全肝重比值分别为（76．3±1．6）％和（71．2±1．0）％（P〈0．05），血清胃泌素水平分别为（441．9±25．9）ng／L和（292．9±14．2）ng／L（P〈0．05）。术后14d，实验组和对照组移植肝重／全肝重比值分别为（94．5±1．7）％和（86．9±1．5）％（P〈0．01），血清胃泌素水平分别为（487．8±29．4）ng／L和（291．7±21．6）ng／L（P〈0．01）。实验组和对照组血清ALT、AST值差异无统计学意义。结论奥美拉唑能促进减体积肝移植术后的肝细胞再生，其作用可能与胃泌素分泌增高有关。     

Ischemic preconditioning of cadaver donor livers protects allografts following transplantation

BACKGROUND: Ischemic preconditioning (IP) has been shown in animal models to protect livers against ischemia/reperfusion injury. The aim of this clinical study is to investigate whether IP of cadaver livers prior to retrieval confers protection on the allografts. METHODS: Cadaveric donor livers were subjected to IP prior to retrieval by clamping of the hepatic pedicle for 10 min followed by reperfusion. Biopsies were obtained from the preconditioned (n=9) and control nonpreconditioned (n=14) liver transplants prior to and 2 hr following reperfusion. Cryosections were stained with antibodies against neutrophils and platelets. RESULTS: IP livers were associated with significantly lower serum levels of aspartate aminotransferase (240+/-98 IU/L vs. 382+/-163 IU/L; P>0.016) and lactate (0.81+/-0.07 mmol/L vs. 1.58+/-0.9 mmol/L; P>0.018) 24 hr following transplantation. Furthermore, recipients of IP livers spent a significantly shorter time in the intensive care unit following transplantation compared to those given nonpreconditioned allografts (1 vs. 2.8+/-1.6 days; P=0.0008). Increases in neutrophil infiltration were detected in 6/14 (43%; P=0.022) and in CD41 deposition in 5/14 (36%; P=0.042) of nonpreconditioned livers. However, none of the IP allografts showed any change in the levels of platelets or neutrophil infiltration following transplantation. CONCLUSION: IP is an effective method of protecting cadaver donor allografts from cold ischemia and subsequent reperfusion injury. IP is also associated with a reduction in the nonspecific inflammatory response.     

大鼠脂肪变性供肝减体肝移植术后的肝再生

目的　探讨大鼠脂肪变性供肝减体肝移植术后的肝再生方式及相关机制。方法　采用 79%标准饲料、2 0 %猪油、1%胆固醇混合喂饲 ,同时以 5 0 %乙醇灌胃每日 1ml/10 0 g ,时间为 4周 ,诱导供肝脂肪变性形成 ,大鼠 60 %减体肝移植模型。观察和比较术后 1、3、7、14d时PCNA、Br dU免疫组织化学及新鲜分离的肝细胞的流式细胞术结果及肝再生率。结果　脂肪变性供肝减体肝移植术后 1、3、7d的肝再生率较正常明显减低 (P <0 .0 1) ;各时点的PCNA标记指数 (P <0 .0 1)和BrdU标记指数差异均有非常显著性 (P <0 .0 1) ;脂变供肝术后的肝细胞增殖指数 (PI)在 7d时最高 (2 6.3 1% ) ,而正常供肝在 3d时最高 (4 2 .0 1% )。结论　大鼠脂肪变性供肝减体肝移植术后肝再生的高峰时间滞后、周期延长。     

缺血预处理对大鼠肝脏缺血再灌注损伤的保护机制

目的验证缺血预处理(IPC)对大鼠肝脏缺血再灌注损伤(I/R)的保护作用,探讨一氧化氮(NO)与蛋白激酶C(PKC)在IPC过程中的作用.方法在原位灌流的大鼠肝脏缺血再灌注模型上,观察IPC的保护作用.同时经肠系膜上静脉注射NO前体L-精氨酸和蛋白激酶C特异性激动剂1,2-二辛酸甘油(DOG)以及两者的特异性阻滞剂N-硝基-L-精氨酸甲酯(NAME)和多粘菌素B,来检测NO和PKC在IPC中的关系.结果预处理可阻止血清谷丙转氨酶(ALT)[(200.86±40.30)U/Lvs.(257.65±20.18)U/L],谷草转氨酶(AST)[(211.06±13.59)U/Lvs.(309.17±24.79)U/L],乳酸脱氢酶(LDH)[(824.73±127.11)U/Lvs.(1118.60±82.21)U/L]及脂质过氧化物(LPO)[(0.414±0.069)mmol/mgvs.(0.531±0.054)mmol/mg]水平升高(P＜0.05),而使组织超氧化歧化酶(SOD)保持在较高水平[(10.33±0.88)U/mgvs.(6.01±0.91)U/mg],(P＜0.05).NO与PKC均可模拟预处理的保护效应.结论缺血预处理对大鼠肝脏I/R有明确的保护作用,NO与PKC发挥IPC保护作用的途径不同.     

缺血预处理与肝脏缺血再灌注损伤的研究

目的 :观察缺血预处理对肝脏再灌注损伤的影响。方法 :通过构建正常大鼠和肝硬化大鼠肝脏 70 %的原位热缺血再灌注损伤模型 ,比较缺血预处理和无预处理组及间歇阻断肝门法对再灌注损伤的影响 ;以肝功酶、能量代谢和过氧化损伤等生物化学指标、组织学病理和细胞超微结构的形态学指标 ,观察不同预处理条件对结果的影响。结果 :各项指标显示 ,正常大鼠中 ,缺血预处理与无预处理组相比 ,可显著减轻再灌注损伤 (P <0 .0 5 ) ,与间歇性阻断肝门组相比也有显著性意义 (P <0 .0 5 ) ;在各个缺血预处理组内 ,缺血预处理 5min(IPC5min)组较IPC10min组和IPC5min× 2 组效果好 (P <0 .0 5 ) ,证实缺血预处理对肝硬化大鼠肝脏再灌注损伤有保护作用。结论 :缺血预处理可减轻肝脏再灌注损伤 ,并优于间歇性阻断肝门法 ,是一种应用方便、效果较好、前景广阔的阻断肝脏血供的新方法     

Ischemic preconditioning improves energy state and transplantation survival in obese Zucker rat livers

Livers from obese donors often have fatty infiltrates and are more susceptible to ischemia-reperfusion injury and subsequent graft dysfunction. This often leads to the exclusion of organs from obese donors. We investigated whether ischemic preconditioning (IP, 10 min ischemia, 10 min reperfusion) preserves cellular metabolism in livers from obese Zucker rats during cold ischemia. Liver samples (-IP and +IP) were collected from obese and control lean rats at different time points of cold ischemia (CI) and analyzed by magnetic resonance spectroscopy (1H- and 31P-MRS) to assess whether IP improves hepatic cellular metabolism. IP significantly improved high energy metabolism in IP livers from obese rats when compared with obese controls during the first hours of CI. At 4 h of cold storage, obese IP livers were not different from control lean non-IP livers. The beneficial metabolic effect of IP on livers form obese rats, however, was absent at 8 h of reperfusion. In contrast, in livers from lean rats, IP resulted in improved high-energy metabolism during the entire observation period of 8 h. In a later part of the study, IP of liver grafts from obese rats before 4 h of cold storage improved recipient survival after graft transplantation. IP of liver grafts from obese rats before 4 h of CI increases 24-h survival of recipient animals from 25% to 88%.     

The results of reduced-size liver transplantation, including split livers, in patients with end-stage liver disease.

We initiated a policy of using RSLT in critically ill patients in June of 1988. Since that time we have performed 30 RSLTs in 29 patients, including 28 children and 1 adult. The mean age of the children was 27 months (range 1 month to 10 years) with 14 (52%) being 1 year of age or less. The mean weight was 11.3 kg (range 2-50 kg) with 20 being 10 kg or less. A total of 22 patients were in the intensive care unit at the time of RSLT including 9 who were intubated. Of the 30 RSLTs, 23 were performed as a primary transplant while 7 were retransplants. Indications for primary transplantation included biliary atresia (n = 11), fulminant hepatic failure (n = 5), neonatal hepatitis (n = 4) and others (n = 3). The RSLT was used in retransplantation for primary nonfunction (n = 2), hepatic artery thrombosis (n = 2), chronic rejection (n = 2), and herpetic hepatitis (n = 1). The size reductions included 18 left lobes, 7 left lateral segments, and 5 right lobes. This group includes the use of the split-liver technique, which was applied to 10 patients (5 livers). The median donor/recipient weight ratio for left lobe transplants was 2:1; left lateral segments was 7.3:1; and right lobes 1.6:1. One year actuarial patient and graft survivals were 68 and 65%, respectively, with a mean follow-up of 10.6 months. The number of children dying awaiting transplantation has been significantly reduced following the introduction of RSLD (3 of 115, 2.6% vs. 12 of 95, 13%; P less than 0.02).     

缺血预处理对大鼠减体积肝移植术后Akt生存信号通路的影响及其意义

目的 探讨缺血预处理(IPC)对大鼠减体积肝移植术后Akt生存信号通路的影响及意义.方法 将36只成年雄性SD大鼠随机分为2组:50%减体积肝移植组(Control组)和IPC组,Western blot检测肝组织总Akt和p-Akt及其下游的p-Bad和p-GSK3β蛋白水平,同时结合血清学和组织病理学分析Akt生存信号通路变化的意义.结果 与Control组比较,IPC组术后6、24 h丙氨酸转氨酶(ALT)水平显著下降(6 h:1064.49±126.53比802.90±82.39;24 h:1401.13±172.73比943.80±116.25,P<0.01);Control组术后24 h,肝细胞明显空泡样变性伴局部坏死,小叶结构破坏,门脉周围水肿、充血,炎症细胞浸润明显,而IPC组损伤减轻;Western blot结果显示:与Control组比较,IPC组术后2、6、24 h肝组织中p-Akt、p-Bad、p-GSK3β蛋白水平上调.结论 IPC明显减轻减体积肝移植术后再灌注损伤,其机制可能与激活Akt生存信号通道密切相关.     

Minimizing oxidative stress by gene delivery of superoxide dismutase accelerates regeneration after transplantation of reduced-size livers in the rat.

Transplantation of reduced-size livers may lead to a hypermetabolic state and increased production of oxygen radicals. Since oxygen radicals may cause liver injury and impair liver regeneration, we tested the hypothesis that overexpression of superoxide dismutase (SOD) in reduced-size livers (RSL) would accelerate regeneration and reduce injury in a rat model of transplantation of RSL. Donor rats were infected with adenoviruses either expressing SOD1 (Ad.SOD1) or beta-galactosidase (Ad.lacZ). Livers were harvested 72 hours later, reduced to 45% of weight, and transplanted. After transplantation, hepatic SOD activity, graft survival, histopathology, AST/ALT release, and bilirubin were examined. Regeneration was evaluated by BrdU-staining, graft weight, and expression of cyclin D1 and p21. In Ad.SOD1-treated livergrafts, SOD activity increased three-fold compared to controls. Survival was dramatically increased in recipients of Ad.SOD1-RSL (100% vs. 20% in Ad.lacZ-RSL), and peak levels of AST/ALT and bilirubin levels were reduced by 75% and 87.5%, respectively (P < 0.001). In histological sections, hepatocyte necrosis decreased from 24% after Ad.lacZ-treatment to 6% after Ad.SOD1-treatment (P <0.001). Regeneration was also accelerated after Ad.SOD1-treatment as demonstrated by an increase of BrdU-stained cells 24 hours after reperfusion and increased liver weight after 1 week. In conclusion, overexpression of SOD1 in RSL prevents primary non-function of reduced-size liver grafts and accelerates liver regeneration.     

Increased intraabdominal pressure impairs liver regeneration after partial hepatectomy in rats

BACKGROUND: There are many experimental studies showing that increased intraabdominal pressure (IAP) reduces liver blood flow, leading to ischemia and portal venous congestion. But, there is no study evaluating the effect of increased IAP on liver regeneration. It is well known that acute liver ischemia and portal venous congestion impair liver regeneration. We, therefore, aimed to determine the effect of increased IAP on liver regeneration in this study. METHODS: Sprague-Dawley rats underwent partial hepatectomy with or without IAP of 12-14 mm Hg for 24 h or sham operation. Rats were randomly divided into six groups: two sham-operated groups, two hepatectomy groups, and two hepatectomy with increased IAP groups. Mitotic index, proliferating cell nuclear antigen (PCNA)-labeling index, and liver regeneration rate as liver regeneration parameters were studied on day 1 or on day 4 after operation. Additionally, serum aspartate transaminase (AST) level and histopathological changes in intestinal mucosa were studied. RESULTS: Hepatectomy with/without increased IAP groups had significantly higher serum AST levels than the sham-operated group on day 1. Serum AST level was found to be significantly higher in the hepatectomy with increased IAP group than in the other groups on day 4. Intestinal mucosal injury was found in the hepatectomy with increased IAP groups on days 1 and 4. Mitotic index and PCNA-labeling index were markedly higher in all hepatectomy with/without increased IAP groups than in the sham-operated groups. However, together with liver regeneration rate, both indices were significantly less in the hepatectomy with increased IAP groups than in the hepatectomy groups both on day 1 and on day 4. CONCLUSION: Maintenance of IAP between 12 and 14 mm Hg for 24 h impaired liver regeneration after partial hepatectomy in rats.     

Early experience with reduced-size liver transplants

Scarcity of small donors results in a high mortality rate for children on liver transplant waiting lists. To alleviate this problem, we have recently started to reduce the size of livers from older donors to use in children. In the last year, a total of 20 liver transplants were performed in 17 patients, including seven reduced-size liver transplants (RSLT) in six children. Mortality on the waiting list has been reduced to negligible amounts compared with a mortality rate of 25% before starting RSLT in patients with acute liver failure or those whose weight was less than 10 kg. Children undergoing RSLT weighed 10.8 +/- 8.5 kg compared with 20.9 +/- 20.3 for all others (NS). Cold ischemia time was significantly longer in the RSLT group (9.5 +/- 3.0 v 6.0 +/- 2.8 hours, P less than .05) as was intraoperative blood loss (9.4 +/- 9.4 v 3.0 +/- 3.5 blood volumes). There was no significant difference in postoperative aspartate aminotransferase and prothrombin time between the two groups. Four children received a RSLT as a primary procedure and three have survived with good liver function. Two patients were retransplanted with RSLT after a failed first transplant and both died of nonhepatic complications. This compares with 11 of 13 survivors in the whole liver transplant group. Causes of death in children who died after RSLT include cytomegalovirus sepsis (2) and myocardial infarction(1).(ABSTRACT TRUNCATED AT 250 WORDS)     

单纯缺血预处理对兔未成熟心脏不足以提供保护作用

目的探讨单纯缺血预处理(IPC)对兔未成熟心脏缺血再灌注损伤的影响.方法利用Langendorff模型灌注幼兔(14-21d)离体心脏,5min缺血、10min再灌的IPC处理后,观察其在生理体温(39℃)下接受30min缺血、40min复灌的血液动力学、冠脉流出液心肌酶及心肌能量的变化.结果复灌后IPC组与对照组在心率(HR)、冠脉流出量(CF)、左室发展压(LVDP)、左室最大上升和下降速率(±dp/dt)恢复率及室性心律失常发生率无明显差别,肌酸磷酸激酶同工酶(CK-MB)漏出量有增多趋势.而IPC组在全心停灌后心脏缺血跳动时间明显延长(P＜0.01),再灌注末心肌ATP含量显著减少(P＜0.001).结论单纯缺血预处理不能保护未成熟心脏免受心肌缺血再灌注损伤,反而可导致心肌细胞的损伤;其原因可能与全心缺血后,心脏不能很快停跳而导致能量消耗过多有关.     

Ischemic preconditioning of the liver: from molecular bases to clinical application

Ischemia-reperfusion injury is produced when an organ is deprived of blood flow (ischemia), which is then restored (reperfusion). In certain circumstances, this injury leads to irreversible organ damage. Several therapeutic strategies have been used to reduce the severity of this injury. One of these strategies is the application of brief and repetitive episodes of ischemia-reperfusion before prolonged ischemia-reperfusion (ischemic preconditioning). In the present article we review the molecular mechanisms through which ischemic preconditioning confers protection against ischemia-reperfusion injury. The application of ischemic preconditioning during liver surgery is discussed, both in normothermic situations such as liver resection and in situations of low temperature such as liver transplantation.     

Ischemic preconditioning prevents free radical production and mitochondrial depolarization in small-for-size rat liver grafts

BACKGROUND: Ischemic preconditioning (IP) renders tissues more tolerant to subsequent longer episodes of ischemia. This study tested whether IP attenuates injury of small-for-size liver grafts by preventing free radical production and mitochondrial dysfunction. METHODS: IP was induced by clamping the portal vein and hepatic artery for 9 min. Livers were harvested 5 min after releasing the clamp. Mitochondrial polarization and cell death were assessed by intravital confocal/multiphoton microscopy of rhodamine 123 (Rh123) and propidium iodide. Free radicals were trapped with alpha-(4-pyridyl 1-oxide)-N-tert-butylnitrone and measured using electron spin resonance. RESULTS: After quarter-size liver transplantation, alanine aminotransferase, serum bilirubin, necrosis, and apoptosis all increased. IP blocked these increases by more than 58%. 5-Bromo-2'-deoxyuridine labeling and increases of graft weight were only approximately 3% and 0.2% in quarter-size grafts without IP, respectively, but increased to 32% and 60% in ischemic-preconditioned grafts, indicating better liver regeneration. Eighteen hours after implantation, viable cells with depolarized mitochondria in quarter-size grafts were 15 per high power field, and dead cells were less than 1 per high power field, indicating that depolarization preceded necrosis. A free radical adduct signal was detected in bile from quarter-size grafts. IP decreased this free radical formation and prevented mitochondrial depolarization. IP did not increase heat shock proteins 10, 27, 32, 60, 70, 72, 75 and Cu/Zn-superoxide dismutase (SOD) but increased heat shock protein-90, a chaperone that facilitates protein import into mitochondria, and mitochondrial Mn-SOD. CONCLUSION: Taken together, IP decreases injury and improves regeneration of small-for-size liver grafts, possibly by increasing mitochondrial Mn-SOD, thus protecting against free radical production and mitochondrial dysfunction.