Apoptosis and chemokine induction after renal ischemia-reperfusion

BACKGROUND: One of the earliest prerequisites for the development of inflammation after ischemia-reperfusion (I/R) is local chemokine expression. We recently demonstrated that apoptosis, characterized by intracellular caspase-activation, contributes to the development of inflammation after I/R. METHODS: The contribution of apoptosis was investigated using the pan-caspase inhibitor Z-Val-Ala-Asp(OMe)-CH2F in a murine model of renal I/R. Renal expression of the chemokines macrophage inflammatory protein-2 (MIP-2) and KC was studied using RT-PCR and immunohistology. Measuring myeloperoxidase activity and serum ureum and creatinine levels assessed neutrophil influx and kidney dysfunction. RESULTS: We demonstrate renal up-regulation of KC and MIP-2 after 1 to 16 hr of reperfusion. Treatment with the caspase inhibitor Z-Val-Ala-Asp(OMe)-CH2F effectively prevented I/R-induced renal apoptosis, KC, and MIP-2 up-regulation after 2 hr of reperfusion as well as neutrophil influx and functional impairment after 24 hr of reperfusion. CONCLUSIONS: These data for the first time show that chemokine induction following I/R is dependent on caspase activation.     

Fine-needle aspiration biopsy in the monitoring of liver allografts. II. Applications to human liver allografts

Serial fine-needle aspiration biopsies (FNAB) were used for clinical monitoring of human liver allografts. Nine liver allograft recipients were monitored with FNAB at 1-3 day intervals. No complications were recorded. All patients underwent at least 1 inflammatory episode of acute rejection; altogether 11 episodes, all reversible, were recorded. The inflammatory infiltrate consisted mainly of lymphoid cells, including lymphoid blasts, with minor involvement of monocytes, monoblasts, and macrophages. Further analysis of lymphoid cell subpopulations by immunoperoxidase techniques demonstrated an increase of T cells during rejection, both the CD4 (T4) and CD8 (T8) subsets were increased. A slight increase of B cells in the graft was also seen. The CD4/CD8 (T4/T8) ratio was first low, peaked at the onset, and decreased toward the end of the episode. No clear correlations to the intragraft cellular events were recorded in corresponding blood specimens. However, an episode of eosinophilia was seen in the blood at the beginning of rejection, correlating with fever in the recipient. Degenerative changes in the parenchymal cells and bile droplets in the hepatocytes, indicating cholestasis and hepatocyte damage, were seen during all episodes of rejection, and these changes persisted even 10 days after the inflammation had subsided. The FNAB-findings correlated well with biochemical laboratory parameters, but the diagnosis of rejection could be established by the FNAB already 1-5 days earlier than elevated serum values indicated liver dysfunction.     

Changes in energy metabolism of allografts after liver transplantation

To evaluate the function of energy metabolism in allografts after liver transplantation, changes in hepatic energy charge levels, oxidative and phosphorylative activities of mitochondria and arterial blood ketone body ratio (acetoacetate/3-hydroxybutyrate; KBR) were studied in piglets. Hepatic energy charge levels decreased to 0.831 +/- 0.010 at 3 days and 0.836 +/- 0.009 at 3 weeks after operation compared to the preoperative value of 0.868 +/- 0.006 (p less than 0.01), and returned to 0.856 +/- 0.007 at 6 weeks. Mitochondrial oxidative and phosphorylative activities were moderately enhanced to 19.14 +/- 2.07 (10(-10) mol ATP/mg of mitochondrial protein/s) at 3 days and 20.89 +/- 1.72 at 3 weeks compared to the preoperative value of 16.74 +/- 2.36, and returned to 16.65 +/- 1.54 at 6 weeks. There was no significant difference in the concentrations of mitochondrial respiratory components, except in cytochrome c + c1. KBR decreased immediately at the beginning of the anhepatic phase and rapidly recovered to the preoperative level within 60 min after revascularization of allografts. There was no change in KBR during the postoperative course except in cases with clinical deterioration. From these results, it is suggested that the mitochondrial capacity for ATP synthesis was enhanced to compensate for the decreased energy charge level and that a decreased KBR is a sign of a critically deranged metabolic function in allografts.     

Apoptosis and necrosis after warm ischemia-reperfusion injury of the pig liver and their inhibition by ONO-1714

BACKGROUND: It is still controversial whether a major mode of cell death during hepatic ischemia-reperfusion (I/R) injuries is apoptosis or necrosis. Moreover, the correlation between these cell deaths and the effects of a novel inducible nitric oxide synthase inhibitor (ONO-1714) has not been studied before. METHODS: Pigs were subjected to 180 min of hepatic warm I/R under extracorporeal circulation. The control group was not administered ONO-1714. In the ONO-1714 group, ONO-1714 was administered 5 min before ischemia at a dose of 0.05 mg/kg through a portal vein catheter. The apoptotic and necrotic changes after reperfusion were examined by terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling and hematoxylin-eosin staining. Nitrotyrosine, active caspase-3, and cytochrome c were examined by immunohistochemistry. The plasma NO + NO, aspartate aminotransferase, and lactate dehydrogenase levels were also examined. RESULTS: In the control group, the frequency of apoptotic cells was only 2.6%; nevertheless, that of necrotic cells was 37% at 24 hr after reperfusion. ONO-1714 significantly attenuated apoptosis and necrosis, the expression of nitrotyrosine, and the increases of the plasma aspartate aminotransferase, lactate dehydrogenase, and NO(2)- + NO(3)- levels in the reperfusion phase. CONCLUSIONS: A major mode of cell death during hepatic warm I/R injury was necrosis, and apoptosis was not dominant. These necrotic changes were caused by the excess production of peroxynitrite, and ONO-1714 greatly attenuated I/R injuries as the result of inhibition of the peroxynitrite production.     

Lymphocyte apoptosis and cell replacement in human liver allografts

BACKGROUND: Apoptosis of graft-infiltrating T cells has been described after rodent liver transplantation. The aim of this study was to assess lymphocyte apoptosis in human allografts. Additionally, kinetics of leukocyte turnover were studied to determine whether apoptotic cells were likely to be of donor or recipient origin. METHODS: Liver biopsy specimens (n=36) taken between days 3 and 1855 were stained with terminal deoxynucleotidyl transferase dUTP nick end-labeling and anti-CD3 to detect apoptotic lymphocytes. Renal allograft and hepatitis C biopsy specimens served as controls. Donor cell turnover was studied in sex-mismatched grafts using Y-chromosome in situ hybridization to detect recipient cells and double immunostaining for leukocyte phenotyping. RESULTS: T-cell apoptosis was prominent in hepatic sinusoids (72% of biopsy specimens) as early as day 3. It ranged from 0% to 18.2% of CD3+ cells (mean 5.28+/-0.82%) and persisted for >14 days, including time points >1 year. There was no difference between biopsy specimens with or without rejection (6.34+/-1.14% and 4.61+/-1.13%, P=NS). Apoptotic cells in portal tracts were less frequent (33% of biopsy specimens) and less abundant (1.13+/-0.36%, P<0.0001). No lymphocyte apoptosis was seen in renal allograft biopsy specimens or hepatitis C biopsy specimens, indicating that it is a distinctive feature of the liver allograft. Persisting lymphocyte apoptosis even after donor lymphocytes had been replaced suggests that recipient lymphocyte deletion must occur. Donor Kupffer cells persisted for many months. CONCLUSIONS: Our results suggest that the sinusoidal microenvironment promotes recipient lymphocyte apoptosis, which may account for the improved outcome of liver grafts compared with other organ allografts.     

Erythropoietin reduces ischemia-reperfusion injury after liver transplantation in rats

Human recombinant Erythropoietin (rHuEpo) has recently been shown to be a potent protector of ischemia- reperfusion injury in warm-liver ischemia. Significant enhancement of hepatic regeneration and survival after large volume partial hepatic resection has also been demonstrated. It was the aim of this study to evaluate the capacities of rHuEpo in the setting of rat liver transplantation. One-hundred-and-twenty Wistar rats were used: 60 recipients received liver transplantation following donor organ treatment (60 donors) with either 1000 IU rHuEpo or saline injection (controls) into portal veins (cold ischemia 18 h, University of Wisconsin (UW) solution). Recipients were allocated to two groups, which either received 1000 IU rHuEpo at reperfusion or an equal amount of saline (control). Animals were sacrificed at defined time-points (2, 4.5, 24, 48 h and 7 days postoperatively) for analysis of liver enzymes, histology [hematoxylin-eosin (HE) staining, periodic acid Schiff staining (PAS)], immunostaining [terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL), Hypoxyprobe] and real-time polymerase chain reaction (RT-PCR) of cytokine mRNA (IL-1, IL-6). Lactate dehydrogenase (LDH) and alanine aminotransferase (ALT) values were significantly reduced among the epo-treated animals 24 and 48 h after liver transplantation (LT). The TUNEL and Hypoxyprobe analyses as well as necrotic index evaluation displayed significant reduction of apoptosis and necrosis in rHuEpo-treated graft livers. Erythropoietin reduces ischemia-reperfusion injury after orthotopic liver transplantation in rats.     

Morphometric image analysis and eosinophil counts in human liver allografts

Histology of liver allografts is the gold standard for diagnosis of acute cellular rejection. However, scoring the severity of rejection and distinguishing it from other infiltrations is not easy. Only one group has evaluated biopsies morphometrically and also suggested that eosinophils are a specific diagnostic feature. We quantitated eosinophil count in 92 biopsies in a group of 25 patients and, in another group of 30 patients, used morphometric image analysis to measure the cross-sectional area and cell density in each portal tract in day 5 protocol liver biopsies. Rejection was diagnosed by pathological evaluation confirmed with clinical and biochemical graft dysfunction graded histologically into mild or moderate-to-severe. The control groups were five patients with no rejection, nine patients with CMV infection, and eight biopsies in eight patients for whom the cause of the liver dysfunction was obscure. The cross-sectional area, the inflammatory cell count of each portal tract and the mean portal tract inflammatory cell density (cells/mm²) increased with the severity of rejection. In each case the regression coefficient was statistically signifinant. Correlating the mean of the total inflammatory cell count with the mean of the portal inflammatory cell density (cell/mm²) gave far better separation of the mild rejection and moderate-to-severe rejection groups. Eosinophils were specific for the presence of acute cellular rejection and increased with the severity of rejection. They were absent in the no rejection group, in the CMV group and in those with obscure liver dysfunction. The eosinophil count fell markedly following treatment of rejection. We conclude that morphometric image analysis can be used to quantify acute cellular rejection and that eosinophils can be specific feature of acute cellular rejection.The author is Shpirer     

肝移植术后肝缺血再灌注损伤保护作用的研究进展

肝缺血再灌注损伤是肝移植术后最常见的并发症。活性氧生成过多导致的氧化应激、自噬、炎症反应是造成肝缺血再灌注损伤的重要步骤。其中,核转录因子红系2相关因子2被认为是抗氧化反应的主要调节因子,PI3K-Akt-mTOR通路被认为是自噬的重要通路,HMGB1-TLR4-NF-κB通路被认为是导致炎症的关键信号通路,本文将从上述通路及调节分子出发,分别从基因、分子、药物等方面研究对肝缺血再灌注细胞的抗氧化、抗炎、调节自噬作用,探究对肝缺血再灌注细胞的保护作用。     

Recipient-derived hepatocytes in sex-mismatched liver allografts after liver transplantation: early versus late transplant biopsies

BACKGROUND: The presence of microchimerism in transplanted tissues is well defined; however, the timeframe of appearance and disappearance of engraftment in liver allograft is unknown. The aims of this study were to analyze for the presence of "recipient-derived cells" in sex-mismatched individuals after liver transplantation, comparing the frequency of "recipient-derived cell repopulation" in early versus late transplant biopsies and to evaluate the relationship between "recipient-derived cell repopulation" and the severity of graft injury. METHODS: Paraffin-embedded liver biopsy samples of 18 recipients were reviewed. Sixteen of them were obtained from recipients with sex-mismatched donors. The remaining two were obtained from recipients with sex-matched donors and were used as controls. Immunohistochemistry and fluorescence in situ hybridization double-labeling method were performed on pretreated slides using anti-human hepatocyte antibody to identify hepatocytes, a mouse anti-human cytokeratin-7 to identify ductal epithelial cells, and using CEPX/Y DNA probes for visualizing X and Y chromosomes. The double-labeled slides were examined systematically using an image analyzer system. RESULTS: The mean time from transplantation to biopsy was 8.1 months. Eleven of the 16 samples obtained from recipients with sex-mismatched grafts demonstrated "recipient-derived hepatocyte repopulation," comprising a mean of 2.1% of the hepatocytes. In the control biopsies, none of the cells demonstrated different nuclear signals from the donor's sex origin. The presence and proportion of "recipient-derived hepatocyte repopulation" rate were significantly higher in early transplant biopsies than in late transplant biopsies (P < 0.05). CONCLUSION: Some hepatocytes of sex-mismatched liver grafts were replaced by "recipient-derived cells" during injury. Such repopulation is more common in the early liver-graft biopsies. The severity of acute cellular rejection appears to have no effect on the rate of recipient-derived repopulation.     

带血管蒂复合组织移植缺血再灌注损伤时的细胞凋亡

目的 探讨带血管蒂同种异体复合组织移植缺血再灌注损伤(IR injury)时的细胞凋亡现象及细胞凋亡在此过程中的生物学效应。方法 通过流式细胞仪、生物电镜、脱氧核糖核酸转移酶介导原位缺口末端标记(TUNEL)技术及DNA电泳等方法,探讨了兔复合组织移植IR损伤时的细胞凋亡现象及其发生的规律。结果 在缺血再灌注后6h,生物电镜即可观察到典型的凋亡细胞;再灌注后6、12h,IR组中TUNEL法可检测到阳性细胞;DNA电泳可观察到典型的梯带;流式细胞仪检测发现,缺血再灌注后12h,IR组细胞凋亡率可达20％。结论 带血管蒂同种异体复合组织移植IR损伤时存在着细胞凋亡,而且,细胞凋亡可能是造成IR损伤的机制之一。     

Regulatory cells develop after the spontaneous acceptance of rat liver allografts

BACKGROUND: After donor-specific transfusion, tolerance to heart transplants is serially passed to naive rats by the adoptive transfer of long-term survivor (LTS)-tolerant splenocytes (SC). We examined whether regulatory cells similarly develop after the spontaneously accepted Lewis (LEW) to Dark Agouti (DA) liver transplants. METHODS: SC from a LTS DA rat with a LEW liver were adoptively transferred to a naive DA 1 day before transplantation of an irradiated (1000 rad) LEW liver. RESULTS: Untreated LEW to DA liver allografts were uniformly accepted; whereas all irradiated LEW liver grafts were rejected. In contrast, when 1.5 x 10 8 DA LTS SC were transferred to a naive DA recipient, all irradiated LEW liver grafts were accepted. When decreased to 1.0 x 10 8 LTS DA SC, only 1 of 4 irradiated LEW grafts was accepted. However, if 1.5 x 10 8 DA SC harvested only 30 days after liver transplantation were transferred, only 2 of 5 irradiated LEW liver grafts were accepted. The serial second and third adoptive transfers of 1.5 x 10 8 DA LTS SC also resulted in the uniform acceptance of irradiated LEW livers. CONCLUSION: Regulatory cells that develop after the spontaneous acceptance of a LEW to DA liver transplant can serially transfer tolerance to new naive LEW liver allograft DA recipients. This "infectious tolerance" is dependent on the time of cell harvest after transplantation and on the cell dose given.     

Telomere shortening and karyotypic alterations in hepatocytes in long-term transplanted human liver allografts

The long‐term fate of aged liver allografts in young recipients who received grafts from older donors is unknown. We evaluated graft aging by analyzing hepatocytic telomere length and karyotypic changes. Seventeen pediatric individuals who underwent living‐donor liver transplantation for congenital biliary diseases were selected. At a median of 10.4 years post‐transplant, ten had tolerated grafts with weaned off immunosuppressants, and seven had idiopathic post‐transplantation hepatitis. Fluorescence in situ hybridization was used to evaluate the telomere signal intensity (TI) and karyotypic changes. First, we measured predictive age‐dependent TI decline with regression analysis of donor livers. The mean TI at the earliest (within a year) and latest biopsies was significantly lower than the predicted TI of the studied allografts. With univariate analysis, a higher abnormal karyotype ratio in the donor liver was correlated with development of idiopathic post‐transplantation hepatitis. With multivariate analysis that included clinical parameters, a greater TI decline at the earliest biopsy was correlated with the development of idiopathic post‐transplantation hepatitis. In conclusion, graft aging as measured by TI decline and donor abnormal karyotype ratio was associated with idiopathic post‐transplantation hepatitis of long‐term transplanted liver allografts.     

Involvement of Rho-kinase in cold ischemia-reperfusion injury after liver transplantation in rats

BACKGROUND: Reperfusion of ischemic tissues is known to cause the generation of reactive oxygen species (ROS) with resultant tissue damage. However, the sources of ROS in reperfused tissues are not fully characterized. We hypothesized that the small GTPase Rho and its target effector Rho-kinase/ROK/ROCK are involved in the oxidative burst in reperfused tissue with resultant reperfusion injury. METHODS: In an in vivo rat model of liver transplantation using cold ischemia for 12 hr followed by reperfusion, a specific Rho-kinase inhibitor, fasudil (30 mg/kg), was administered orally 1 hr before the transplantation. RESULTS: Fasudil suppressed the ischemia-reperfusion (I/R)-induced generation of ROS after reperfusion (P<0.01) and also suppressed the release of inflammatory cytokines (tumor necrosis factor-alpha, interleukin-1beta) 3 hr after reperfusion, resulting in a significant reduction of I/R-induced hepatocellular injury (P<0.05), necrosis, apoptosis (P<0.01), and neutrophil infiltration (P<0.0001) 12 hr after reperfusion. All animals receiving a graft without fasudil died within 3 days, whereas 40% of those receiving fasudil survived (P<0.001). CONCLUSIONS: The present study demonstrates that Rho-kinase-mediated production of ROS and inflammatory cytokines are substantially involved in the pathogenesis of hepatocellular necrosis and apoptosis induced by cold I/R in vivo and that Rho-kinase may be regarded as a novel therapeutic target for the disorder.     

Orthotopic liver allografts in the pig

The results obtained in fifty-two orthotopic liver allografts in unselected pigs without the use of immunosuppressive therapy are reported. One third of the animals showed classic signs of rejection. The others tolerated the liver allograft for a relatively long time, five animals living over one year.