Identification of two down-regulated genes in rat liver allografts by mRNA differential display

Total RNA differential display (DD) using random primers was performed for rat orthotopic liver transplantation (OLT) models. DA (RT1^a) donor livers were transplanted into DA, PVG (RT1^c), and LEW (RT1^l) recipients: (1) syngeneic OLT (DA-DA): no rejection occurs; (2) allogeneic OLT (DA-PVG): rejection occurs, but is naturally overcome without immunosuppression; (3) allogeneic OLT (DA-LEW): animals die of acute rejection within 14 days. cDNA was isolated from selected bands, re-amplified for sequencing, and confirmed by Northern blots. Two down-regulated genes were observed in day-7 allogeneic OLT livers (DA-PVG, DA-LEW), while they were consistently expressed in day-7 syngeneic OLT (DA-DA) livers. These two genes were identified as α-glutathione sulfotransferase (α-GST) Ya gene and estrogen sulfotransferase (EST), respectively. Northern blots confirmed that their expression was down-regulated in OLT (DA-PVG) livers on days 7–26 and gradually restored. The mRNA expression of GST and EST may be good markers to predict rejection or induction of tolerance. Received: 14 December 1999 Revised: 28 September 2000 Accepted: 16 March 2001     

Involvement of autoimmunity against nuclear histone H1 in liver transplantation tolerance

BACKGROUND: Our recent studies suggested that anti-histone H1 autoantibody (auto-Ab) plays an important role in experimental and clinical liver allograft tolerance as a natural immunosuppressive factor. The present study aimed to explore how the autoimmune response against histone H1 is involved in tolerance induction. METHODS: The measurement of anti-histone H1 auto-Ab and immunohistochemical analysis were performed in serum and liver allografts after orthotopic liver transplantation (OLT). To compare the auto-Ab response against histone H1 between the recipients of rejector (DA-LEW) and tolerogenic (DA-PVG) OLT models, na?ve recipients were immunized with calf thymus histone H1. The immunosuppressive state of histone H1-immunized rats was assayed by mixed lymphocyte reaction (MLR). RESULTS: Anti-histone H1 Ab titer was transiently increased during the rejection phase after OLT (days 7-21) in the DA-PVG combination, while no such response was confirmed in the DA-LEW acute rejection model. Nuclear histone H1 antigens were found in the cytoplasm and the extracellular environment in liver allografts at the rejection phase in the tolerogenic model but not in the rejector model, resulting from the transient induction of anti-histone H1 auto-Ab in recipient PVG rats after OLT. Low dose and short-term immunization with histone H1 upregulated the anti-histone H1 Ab titer in na?ve PVG rats, which exhibited a low allogeneic immune response, while no such response was found in na?ve LEW rats. CONCLUSIONS: These results suggest that the sensitivity to nuclear antigens such as histone H1 may be a key factor determining the acceptance or rejection of donor liver grafts, at least in DA-PVG and DA-LEW combinations.     

Restoration of tolerance to rat hepatic allografts by spleen-derived passenger leukocytes

The tolerance induced by orthotopic liver transplantation (OLT) in certain combinations of rat strains can be prevented by total body irradiation (TBI) of the donor. We demonstrate here that the intravenous inoculation of splenic leukocytes into irradiated donors before OLT could re-establish tolerance in association with a state of microchimerism detected in the recipients. When donor DA (RT1^a) strain rats were irradiated with 1000 rad 24 h before liver harvesting and subsequent liver implantation into PVG recipients, five out of six rats died from rejection in this normally tolerogenic OLT (DA-PVG) combination. Injection of 1.5x10⁸ splenic leukocytes from naive DA rats into the irradiated DA donor rats 24 h before OLT restored the tolerogenic potential of the liver allografts. Immunofluorescence assay revealed an increased number of donor (DA) type cells in the PVG recipient bearing a repopulated DA liver, compared to the PVG recipient of an irradiated liver. These results suggest that passenger leukocytes reconstituted by splenic leukocytes have the capacity to protect liver allografts.     

The effect of selective inhibition of inducible nitric oxide synthase on cytochrome P450 after liver transplantation in a rat model

BACKGROUND: Activity levels of cytochrome P450 (CYP) provide markers for liver function and graft rejection episodes after orthotopic liver transplantation (OLT). Some in vitro studies have shown decreased CYP activation of inducible nitric oxide synthase (iNOS) in rejecting liver grafts. The aim of this study was to evaluate CYP isoenzyme activity changes in vivo and to examine histopathologic aspects during inhibition of iNOS after treatment with aminoguanidine (AG) using OLT in the rat. MATERIALS AND METHODS: Thirty DA-(RT1av1) rats that served as donors and LEWIS-(RT(1)) rats as recipients were divided into three groups: group I (controls, syngeneic rats; n = 6), group II (allogeneic rats without immunosupression; n = 11), and group III (allogeneic rats with AG treatment; n = 13). On postoperative days 5, 8, and 10 we performed laboratory investigations and liver biopsies for histopathologic investigations. RESULTS: On postoperative day 5, activities of CYP-1A1 and -3A4 were significantly lower (P = .022) in group III and the activity of CYP-1A2 higher (P < .05) compared with group II. At postoperative days 8 and 10, the activities of all CYP isoenzymes were significant higher in AG-treated rats (group III) in contrast with group II after allogeneic OLT without immunosuppression. Histopathologic findings revealed less distinct rejection signs in group III specimens after AG treatment compared with group II. CONCLUSION: Summarizing our results, we concluded that AG treatment led to increased CYP activity and less distinction of graft rejection after OLT in rats.     

Bone marrow-derived liver stem cell and mature hepatocyte engraftment in livers undergoing rejection

BACKGROUND: The definitive therapy for end-stage liver disease is orthotopic liver transplantation (OLT). However, rejection is still a major cause of mortality and morbidity following OLT. Hepatocyte transplantation has been used experimentally to treat liver diseases. The aim of this study was to investigate whether bone marrow-derived liver stem cells (BDLSC) and mature hepatocytes could repopulate transplanted livers undergoing rejection. METHODS: OLT was carried out from D'Agouti (C3-positive female) into Lewis (C3-negative female) rats. BDLSC were transplanted from Lewis (male) into livers of D'Agouti (female) rats. Group A (n = 9) received intraportal normal saline. Groups B (n = 9) and C (n = 9) underwent intraportal transplantation of mature hepatocytes (Lewis female, 0.75 x 10(7)) and DBLSC (Lewis male, 5 x 10(4)) respectively. All groups received subtherapeutic immunosuppression (Cyclosporin 0.25 mg/kg/d) for 13 days. Liver repopulation was assessed using immunohistochemistry (C3 antigen-negative cells), in-situ hybridization, (Y-chromosome-positive BDLSC) and histologic assessment (hematoxylin and eosin) for rejection. RESULTS: BDLSC and mature hepatocytes repopulated 62 +/- 12.3% and 2.5 +/- 1.7% of rejecting livers, respectively. BDLSC demonstrated formation of hepatic lobules and portal triads with little evidence of rejection 36 days after discontinuation of immunosuppression. CONCLUSIONS: BDLSC can repopulate livers undergoing severe rejection. Moreover, BDLSC can differentiate into hepatocytes and cholangiocytes. This finding may have important clinical implications.     

Clusterin may be involved in rat liver allograft tolerance

Little is known about the possible role of complement inhibitors on tolerance induced by liver allografts. Clusterin, which is a plasma glycoprotein, inhibits cytolytic membrane attack complex (MAC) of complement by binding to soluble C5b-7 complex. The role of clusterin in relation to the naturally achieved tolerance in a rat orthotopic liver transplantation (OLT) has not been investigated before. Here we determined the kinetics of clusterin expression at different post-transplantation time points in a tolerogenic model (DA-PVG) where rejection was naturally overcome without any immunosuppressive drugs in comparison with the syngenic OLT model (DA-DA). Peripheral blood and liver tissues were taken from OLT at various post-operative time points. A strong expression of soluble clusterin was observed on post-transplantation day 7, which occurred at the peak of the rejection in this tolerogenic OLT model. The expression of clusterin remained strong even after tolerance was achieved. The intensity of clusterin expression was much stronger when compared with the syngenic OLT (DA-DA) model after OLT. A strong expression of clusterin mRNA was also observed in the tolerogenic model on post-OLT day (POD) 7 and the expression persisted when compared with the syngenic model on post-OLT day 60. Our data have shown that the strongest levels of clusterin during the reaction phase in tolerogenic OLT may be involved in tolerance induction.     

A study of tolerance induced by liver transplantation on intestinal graft in the rat]

In some strain combinations of rats, orthotopic liver transplantation (OLT) permits long-term donor-specific survival of fully allogeneic kidney, heart or skin grafts. The difficulties encountered in the clinical situation to obtain tolerance of small-bowel transplantation (SBT), in spite of massive non-specific immunosuppression, led us to study possible liver-induced tolerance in SBT. Inbred DA (RTIa) and PVG (RT1c) rats were used respectively as donors and recipients and divided in two groups: group 1: SIT alone (n = 6); group 2: combined OLT/SBT (n = 6). SIT was performed 17 days after OLT. No immunosuppressive treatment was given to the recipients. Biopsies of small-bowel grafts were performed in both groups at various times after small bowel engraftment. All animals in group 1 showed evidence of acute rejection of the graft between days 6 and 9 post-graft. The histologic pattern of rejection associated lamina propria (LP) mononuclear cell infiltration, crypt lesions and villous atrophy at the end-point of rejection. In group 2, long-term survival (> 100 days) of small bowel grafts was achieved in five of the six animals in spite of strong mononuclear cell infiltration in the LP, which peaked two months after small bowel grafting but then disappeared partially. This striking mononuclear cell infiltrate contrasted with only minor epithelial damage. These data demonstrate that liver grafting can enhance the survival of a small-bowel graft from the same donor in a rat model. Histological findings show that an intense immunological reaction takes place within liver-induced tolerated small-bowel grafts.     

趋化因子IP-10及其受体CXCR3在大鼠肝移植急性排斥反应中的作用

目的探讨趋化因子IP-10及其受体CXCR3的表达在大鼠肝移植手术前后的动态变化,分析其与肝移植急性排斥(acute rejection,AR)的关系。方法改良"二袖套"法建立大鼠原位肝移植模型和急性排斥模型,分为4组:手术创伤组,肝移植无排斥组,肝移植急性排斥组,FK506组。ELISA法检测血清IP-10表达。流式细胞仪检测外周血淋巴细胞CXCR3的表达,用Cellquest软件分析阳性细胞百分率。半定量RT-PCR检测各组第7天肝脏组织CXCR3-mRNA的表达。结果①各组大鼠手术后外周血趋化因子IP-10及其受体CXCR3表达明显升高;②AR组在术后第5天起IP-10及其受体CXCR3表达均高于各对照组(P0.01);③AR组大鼠在移植后第7天,外周血IP-10和CXCR3的表达随着AR组RAI积分的升高而逐步升高,相关系数分别为0.89和0.92(P0.05)。结论血清中趋化因子IP-10及其受体CXCR3的高表达与AR密切相关,有望成为诊断AR较特异、敏感的指标。     

The immunological role of lipid transfer/metabolic proteins in liver transplantation tolerance

BACKGROUND: In a rat tolerogenic orthotopic liver transplantation (OLT) model, recipient serum after OLT (post-OLT serum) has been reported to prevent allograft rejection. A previous proteomic study indicated that apolipoprotein E (apo-E), which is an important factor for cholesterol transportation, is expressed at the latter tolerogenic phase after OLT. It has also been known that adipose tissue-derived adipokine, adiponectin, is an essential factor for fatty acid catabolism. This study aimed to characterize the role of lipid transfer/metabolic proteins in liver transplantation tolerance. METHODS: To identify the apo-E and adiponectin in post-OLT serum, Western analyses and enzyme-linked immunosorbent assay (ELISA) were performed, respectively. The immunosuppressive activities of those factors were evaluated by inhibition of the mixed lymphocyte reaction (MLR). RESULTS: Western analyses showed that the mobility of apo-E was shifted at the latter tolerogenic phase after OLT in a natural tolerance model, and a similar phenomenon was confirmed in the serum of a drug-induced tolerance model (rejection model+cyclosporin A (CsA); 0 to 14 days) after cessation of CsA. Further study revealed that neutralization of modified apo-E in post-OLT serum reduced the immunosuppressive activity. Additionally, plasma adiponectin was significantly elevated at the latter phase after OLT, and possessed MLR-inhibitory activity. CONCLUSIONS: These results suggest that the mobility shift of apo-E and/or the up-regulation of adiponectin may be necessary for overcoming the rejection, recovering the liver allograft function, and following tolerance induction in experimental OLT models, and may be useful as one indicator to surmise the prognosis after liver transplantation.     

Wistar-SD大鼠原位肝移植急性排斥反应的观察

目的 观察Wistar-SD大鼠原位肝移植（OLT）术后发生急性排斥反应时的表现及其判断方法。方法 观察大鼠术后生存状况，采用肝功能检查及组织病理学检查等方法研究OLT模型大鼠发生急性排斥反应的表现，结果Wistar-SD实验组OLT术后发生中，重度急性排斥反应。实验组大鼠肝移植术后血清ALT，AST，TB于第1～3天及第7天各指标数值呈明显上升，高于对照组各相应时点，差异仃统计学意义（P〈0.05）：结论Wistar-SD大鼠OLT模型可发生巾，重度急性排斥反应，其肝功能指标的变化可以说明急性排斥反应是否已发生.     

Assessment of serum matrix metalloproteinases MMP-2 and MMP-9 after human liver transplantation: increased serum MMP-9 level in acute rejection

BACKGROUND: Alterations in synthesis and breakdown of extracellular matrix components play a role in acute rejection after orthotopic liver transplantation (OLT). Matrix metalloproteinases (MMPs) are capable of degrading basement membranes and are involved in the process of tissue remodelling in inflammation and liver fibrosis. METHODS: We examined MMP-2 and MMP-9 in serum of 33 patients before and during 1 year after OLT, in 60 controls as well as in some specimens of cirrhotic liver and control liver tissue. RESULTS: Serum MMP-2 levels before OLT were significantly higher compared with controls and decreased approximately 50% after OLT. Also, the MMP-2 content of cirrhotic liver specimens was significantly higher compared with normal liver. MMP-9 in serum and liver tissue of patients were similar to controls, but serum levels showed a peak at 1 week after OLT. At this time-point, total and active/inhibitor-complexed MMP-9 was significantly higher in patients with rejection (n=13) compared with those without rejection (n=20). The relative amount of MMP-9 in the active/inhibitor-complexed form did not differ between each group over time. Immunohistochemical staining at 1 week after OLT showed increased numbers of MMP-9-positive inflammatory cells in the portal triads of patients with rejection. CONCLUSIONS: Patients with acute allograft rejection have elevated serum levels of MMP-9 1 week after OLT, which was most likely derived from inflammatory cells. An increased MMP-2 serum level and liver tissue content was found in patients with cirrhosis, which decreased after OLT. These observations indicate active involvement of MMP-2 and -9 in end-stage liver disease and OLT.     

Identification of the indoleamine 2,3-dioxygenase nucleotide sequence in a rat liver transplant model

A tryptophan catabolizer, indoleamine 2,3-dioxygenase (IDO) is highly expressed in the placenta and plays an essential role in maternal tolerance. Recent data have shown that the administration of an IDO inhibitor blocked not only maternal tolerance but also liver allograft tolerance. However, little is known about the induction of IDO in liver allografts, although a gene specific for tryptophan 2,3-dioxygenase (TDO) is believed to be expressed in the liver. In the present study, we investigated whether IDO is induced in liver allografts. Synthetic oligonucleotide primers based on the mouse IDO cDNA sequence were used to amplify RNA derived from livers of donor, syngeneic or allogeneic OLT rats. RNA encoding IDO was induced in the rat allogeneic liver after orthotopic liver transplantation (OLT), but not in syngeneic OLT. The rat nucleotide sequence of the RT-PCR products obtained from OLT livers revealed identities of 89% homology to the mouse IDO and of 68% to the human IDO. This study demonstrated the presence of RNA encoding IDO in allogeneic OLT livers, which may be involved in the immune response after liver transplantation.     

“二袖套法”大鼠原位肝移植的技术改进

目的 探讨大鼠原位肝移植(OLT)模型的技术改进方法,并观察移植后的排斥反应。方法 将“二袖套法”大鼠肝移植技术进行了改进;并行SD→SD,SD→Wistar大鼠肝移植各30例,观察术后排斥情况。结果 全组肝移植手术无肝期约为15min。大鼠无手术死亡。SD-SD大鼠肝移植后3周内存活率为97％;SD→Wistar大鼠肝移植后8～15d死亡,组织病理学证实存在不同程度的排斥反应。结论 采用该改良大鼠肝移植方法可明显缩短手术时间,降低术后并发症,提高移植大鼠的术后生存率。SD-Wistar大鼠的肝移植可作为较理想的研究肝移植排斥反应的动物模型。     

IL-15在同种异体移植物急性排斥反应中的作用

目的：探讨非T细胞来源淋巴细胞活化因子IL-15在大鼠心、肝移植急性排斥反应模型中的作用。方法：LEW重组鼠系,1A(RT1^a)和LEW(RT1^1)分别作为供受体建立心、肝移植急性排斥反应模型为实验组;LEW→LEW作受体建立无排斥反应模型为同期对照组。术后1,3,5,7d各时点分别处死动物。采用Microarray、免疫组织化学及Western-blot技术分别检测移植物IL-15及其受体的表达部位,时间及程度,并与IL-2,IFN-γ的表达状况,淋巴细胞的浸润程度作对比。结果：实验组移植物术后3d开始发生急性排斥反应。Microarray示IL-15、IL-2,IL-2R升高了3-3.5倍。免疫组化及Western-bloting结果显示实验组IL-15术后第1天在血管内皮细胞上即有表达,至第7天开始减弱。第5天同时出现在移植实质细胞上。IL-2于术后第3天才开始出现,第5天表达最强。其表达部位均在移植物血管周围浸润的淋巴细胞上,而血管内皮细胞上无阳性表达。IFN-γ的表达与IL-2同步。结论：IL-15在大鼠心、肝移植物急性排斥反应中的表达时间早于IL-2和IFN-γ的表达,其表达部位也与之不同。IL-15的表达是急性排斥反应发生的早期事件,可能是存在于IL-2之外的参与急性排斥反应发生的另一途径。     

供肝不同程度的缺血再灌注损伤对大鼠肝移植后急性排斥反应的影响

目的 探讨大鼠供肝不同程度的缺血再灌注损伤(IRI)对肝移植后急性排斥反应(AR)的影响.方法 用随机数字表法将大鼠分为6组,每组供、受者各12只,同系移植组供肝热冷缺血时间分别为0～2和80 min,同种移植1～4组供肝热冷缺血时间分别为0～2和80 min、0～2 min和10 h、15和80 min及15 min和10 h,假手术组仅开腹游离肝脏后关腹,不行肝移植.肝移植采用改良的Kamada二袖套法.术后1、3、5、7 d,分别处死每组3只受者,取移植肝组织,行病理学检杏观察病理改变和IRI程度,按照Banff系统分级标准对AR进行评分,采用免疫组织化学法和实时聚合酶链反应法检测移植肝组织Fas、穿孔素及颗粒酶B的蛋白和mRNA表达,采用原位末端标记法检测移植肝细胞的凋亡情况.结果 假手术组、同系移植组及同种移植1～4组移植肝组织病理学改变及IRI损伤程度依次加重.术后1、3、5、7 d,假手术组、同系移植组及同种移植4组未发现AR,同种移植1～3组AR明显;随着术后时间延长,同种移植1～3组AR评分均逐渐升高,各组内不同时间点的差异均有统计学意义(P<0.05);术后相同时间点,同种移植1～3组AR评分依次升高,组间差异均有统计学意义(P<0.05).术后各时间点,假手术组、同系移植组移植肝组织中Fas、穿孔素和颗粒酶B的蛋白及mRNA均无表达,F组仅有少量表达,同种移植1～3组较其他组的表达明显升高(P<0.05);术后相同时间点,同种移植1～3组的表达量依次升高,两两比较,差异均有统计学意义(P<0.05).结论 肝移植后AR的程度与一定程度内的IRI呈正相关,但如IRI造成移植肝严重损伤,则AR的发生明显降低,Fas/FasL和穿孔素/颗粒酶B细胞凋亡途径在其中发挥重要作用.     

褪黑素对大鼠移植肝组织GRP-78及CHOP表达的影响

目的 通过检测褪黑素(MEL)对肝移植大鼠肝脏内质网应激(ERS)通路相关分子葡萄糖调节蛋白-78(GRP-78)及CCAAT增强子结合蛋白同源蛋白(CHOP)表达的影响, 探讨MEL对移植肝的作用。 方法 采用"磁环法"制作大鼠原位肝移植模型, 雄性SD大鼠随机分为3组:假手术组(Sham组)、原位肝移植组(OLT组)、原位肝移植+褪黑素处理组(OLT+MEL组), 每组各8只。术后24 h, 获取血清样本及肝脏标本。检测血清丙氨酸转移酶(ALT)及天冬氨酸转移酶(AST)水平, 苏木素-伊红(HE)染色观察各组肝组织病理学改变, 采用聚合酶链反应和蛋白免疫印迹试验检测GRP-78及CHOP的信使核糖核酸(mRNA)和蛋白表达水平。 结果 与Sham组比较, OLT组血清ALT、AST显著升高(均为P < 0.01), 肝组织损伤严重, GRP-78及CHOP在mRNA和蛋白水平表达明显增加(均为P < 0.01)。与OLT组比较, OLT+MEL组大鼠ALT、AST水平明显降低(均为P < 0.05), 肝组织损伤减轻, GRP-78及CHOP mRNA和蛋白表达水平明显降低(均为P < 0.05)。 结论 褪黑素能降低移植肝ERS相关分子GRP-78及CHOP在mRNA和蛋白水平的表达, 这可能是它减轻移植后肝脏损伤的机制之一。     

Role of antinuclear antibodies in experimental and clinical liver transplantation

OBJECTIVE: We recently reported that autoreactive antibodies (Abs) against nuclear histone H1 was transiently induced at an early phase after orthotopic liver transplantation (OLT) in a tolerogenic rat OLT model and possessed immunosuppressive activity. It was also reported that nuclear antigen, high-mobility group box 1 (HMGB1) protein was one of the initiators of the immune reaction. The present study sought to evaluate the role of antinuclear Abs in experimental and clinical liver transplantation. MATERIALS AND METHODS: We prepared 3 animal models: natural tolerance model (DA liver into PVG); acute rejection model (DA liver into LEW); and drug-induced tolerance model (acute rejection model + cyclosporine [CsA]). In addition, we examined clinical samples, including 1 drug-free patient, to measure the antihistone H1/HMGB1 titers at various times after OLT. RESULTS: In a natural tolerance model, antihistone H1 and HMGB1 Ab was induced during the rejection and the tolerance induction phases, respectively. Those Ab responses were also confirmed in a drug-induced tolerance model, whereas no such responses were shown in an acute rejection model. In our clinical drug-free patient, antihistone H1/HMGB1 titer was significantly higher after cessation of CsA than that in healthy volunteers. CONCLUSIONS: Antinuclear Ab is actively expressed in accordance with overcoming rejection episodes with subsequent tolerance induction in both a natural tolerance model and a drug-induced tolerance model. We also observed a similar tendency in our clinical drug-free patient. These results suggested that antinuclear Abs may be useful markers to determine the timing to withdraw immunosuppressants.     

微透析技术连续监测大鼠肝移植后吲哚胺2,3-双加氧酶在体活性

目的 观察肝移植后肝内吲哚胺2,3-双加氧酶(IDO)在体活性,探讨肝移植免疫排斥对IDO酶活性的影响.方法 施行假手术、同品系(SD→SD)及异品系(Wistar→SD)大鼠肝移植各10例.术后在肝内植入微透析探针,连续收集透析液,HPLC测定色氨酸及犬尿氨酸浓度,以表明IDO酶在体活性.结果 假手术、同品系及异品系组在术后2周内色氨酸浓度均值分别为97.14、85.71、53.07nmol/L(P＜0.05),犬尿氨酸浓度均值分别为3.46、14.58、46.79 nmol/L(P＜0.05),异品系组术后第2天犬尿氨酸浓度即开始增加(20.03nmol/L),第7天达到峰值(70.75nmol/L),此后保持在40.00nmol/L水平以上.结论 同品系或异品系均能诱导移植后肝内IDO酶活性增加,且异品系大鼠肝移植后IDO酶活性表现早而强烈.

Abstract：

Objective To observe the activity of indoleamine 2, 3-dioxygenase (IDO) enzyme in vivo after rat liver transplantation, and the effects of liver transplantation rejection on IDO enzyme activity.Methods Ten SD rats were subjected to othotopic liver transplantations respectively in allogenic OLT group (SD→SD) and heterogenic OLT group (Wistar→SD). In the other 10 SD rats, the blood supply to the liver was obstructed for 15 min for simulating the anhepatic period in the OLT group ( sham group). An in vivo rat liver microdialysis-HPLC system was established on the day I after OLT. The concentrations of kynurenine and tryptophan in dialysate samples were continuously monitored quantitatively and reproducibly for more than 2 weeks in the same animal. Results The average concentrations of tryptophan in dialysate were 97. 14, 85.71, 53.07 nmol/L respectively in the sham, allogenic OLT and heterogenic OLT groups respectively. The concentrations of kynurenine were 3.46, 14. 58, 46.79 nmoL/L in the sham, allogenic OLT and heterogenic OLT groups respectively. The concentration of kynurenine was increased significantly on the day 7 after surgery in heterogeneic OLT group (70. 75 nmol/L). Conclusion The transplantation surgery can induce the activity of IDO enzyme in vivo and accelerate the metabolism of tryptophan in the liver allografts.     

Coagulation disorders during orthotopic liver transplantation

Coagulation disorders have been noted during orthotopic liver transplantation (OLT) especially just after reperfusion of the grafted liver. This study was undertaken to clarify the coagulation disorders following reperfusion of the liver graft. OLT was carried out in adult mongrel dogs using a cuff technique. Fresh and 24-hour preserved livers were grafted. Platelet count (P1), activated partial thromboplastin time (A-PTT), prothrombin time (PT) and plasma fibrinogen levels (Fng) were measured before and after OLT. Next perfusate obtained from fresh livers or preserved livers for 24-hours or 48-hours was determined for their ability of inducing coagulation disorders when infused in untreated dogs, and was also tested for their activity of platelet aggregation, tissue thromboplastin (F-III), and plasminogen activator (PA). All dogs which received preserved livers showed a marked coagulation disorders including a decrease in P1 and Fng, and prolongation of A-PTT and PT, but the dogs with fresh liver grafts did not. Infusion of the perfusate collected from a perfusion of the preserved liver induced similar coagulation disorders in untreated dogs. The perfusate obtained from the preserved liver showed significant increased F-III activity as compared with that from fresh liver. On the other hand, neither direct platelet aggregation activity nor PA activity was seen or very low if any. These results indicate that F-III liberated from a damaged liver is responsible for the coagulation disorders after reperfusion of the graft in liver transplantation.