The effects of a cyclooxygenase-2 inhibitor, FK3311, on total hepatic ischemia-reperfusion injury of the rat

BACKGROUND/AIMS: This study was designed to investigate the effects of a selective cyclooxygenase-2 inhibitor, FK3311, on warm ischemia-reperfusion injury of the rat liver. METHODOLOGY: Male Sprague-Dawley rats were used in this experimental study. Total hepatic ischemia was induced with a clamping portal triad. The animals were divided into two groups: the control group and the FK group, in which FK3311 (FK, 1.0 mg/kg) was administered via the penile vein. The serum levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), and lactate dehydrogenase (LDH) were measured 2 h after reperfusion, while those of thromboxane (Tx) B2 and 6-ketoprostaglandin (PG) F1alpha (stable metabolites of TxA2 and PGI2) were measured 30 min after reperfusion. The liver tissue blood flow was measured at preischemia, end-ischemia, and 30, 60, 90, and 120 min after reperfusion. The liver tissues obtained from animals at 2h after reperfusion were excised for histopathology. RESULTS: The serum levels of AST, ALT, and LDH were significantly lower in the FK group than in the control group. Similarly, in the FK group, the serum levels of TxB2 were significantly lower than in the control group. By contrast, the 6-keto-PG F1a levels were not significantly reduced. The liver tissue blood flow at 120 min after reperfusion was significantly higher in the FK group than in the control group. The histopathological study showed that hepatic tissue damage was milder in the FK group than in the control group. CONCLUSIONS: FK has protective effects on hepatic ischemia-reperfusion injury stemming from the marked inhibition of TxA2.     

Protective effect of methylprednisolone and of intermittent hepatic pedicle clamping during liver vascular inflow occlusion in the rat

BACKGROUND/AIMS: One of the main causes of postoperative morbidity and mortality following major hepatic resection is hepatic ischemia deliberately designed to reduce intraoperative hemorrhage. This study assessed the effects of intermittent or continuous hepatic ischemia and reperfusion with or without methylprednisolone pretreatment in the rat. METHODOLOGY: One hundred and eighty rats were divided into 3 groups undergoing hepatic ischemia of 60, 90, and 120 minutes total duration. Each group of rats were subdivided to receive either a continuous Pringle maneuver, or 30 min or 15 min of intermittent liver pedicle clamping. Ten minutes before ischemia induction, 10 rats from each group were pretreated with intravenous 3 mg/100 g bw methylprednisolone. RESULTS: With continuous hepatic pedicle clamping the rat survival rates inversely correlated with the duration of ischemia (survival: 70%, 40%, and 20% with ischemia of 60, 90, and 120 min). Survival rates at 15-min and 30-min intermittent ischemia groups were significantly higher than in the continuous clamping group (p<0.05). Methylprednisolone pretreatment did not significantly increase survival but resulted as a significant reduction in liver enzyme release (AST, ALT), at 90 min (p<0.05) and at 120 min (p<0.05) in the continuously clamped groups. When ischemia lasted 120 min, methylprednisolone pretreatment was associated with higher preservation of ATP liver content (p<0.05). CONCLUSIONS: This study confirms that intermittent hepatic pedicle clamping significantly improves survival in rats undergoing hepatic vascular inflow occlusion with a decrease in transaminase release and greater maintenance of intrahepatic ATP after prolonged total ischemia when animals were pretreated with methylprednisolone.     

Pentoxifylline inhibits liver expression of tumor necrosis factor alpha mRNA following normothermic ischemia-reperfusion

Background: Pentoxifylline (PTX) has been shown to reduce hepatic injury after normothermic ischemia and reperfusion (I-R) in rat liver. Aim: The aim of this study was to evaluate the effects of PTX on liver expression of tumor necrosis factor alpha (TNFα) mRNA following normothermic liver I-R. Materials and methods: A segmental normothermic ischemia of the liver was induced in male Lewis rats by occluding the blood vessels including the bile duct to the median and left lateral lobes for 90 min. At the end of ischemia the nonischemic liver lobes were resected. Rats were divided into three groups: group 1, control Ringer lactate administration; group 2, PTX treatment; group 3, sham-operated control rats. PTX (50 mg/kg) was injected intravenously 30 min before and 60 min after induction of ischemia. Survival rates were compared and the serum activities of TNFα, serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), and lactate dehydrogenase (LDH) were measured. Histology of the liver was assessed 6 h after reperfusion. Liver TNFα mRNA was assessed by PCR amplification at 0, 60, 120, and 210 min after reperfusion. Results: PTX treatment significantly increased 7 day survival (93.3%) compared with nontreated control rats (46.6%, p<0.007). The extent of liver necrosis and the release of liver enzymes were significantly decreased after PTX treatment. Serum activities of TNFα were significantly decreased and liver expression of TNFα mRNA was inhibited after PTX treatment. Conclusion: PTX protects the liver from ischemic injury and inhibits liver expression of TNFα mRNA.     

Studies on mechanisms of augmentation of liver regeneration by cyclosporine and FK 506.

Evidence could not be found of immune modulation of liver regeneration. The powerful immunosuppressive drug FK 506, which augments the response after partial hepatectomy in normal rats, had the same effect in T cell-deficient nude rats. The cytotoxicity of natural killer cells in treated nude rats was not significantly changed by FK 506 therapy. However, the serum of FK 506-treated nude rats increased hepatocyte proliferation when added to third-party hepatocyte cultures, suggesting that FK 506 had induced a serum growth factor in the nude rats or had suppressed an inhibitory factor. A hypothesis was advanced that FK 506 (and cyclosporine) affects hepatic growth by nonimmunological pathways.     

Preventive Effect of FK 506 (Tacrolimus Hydrate) on Experimentally Induced Acute Liver Injury in Rats

The aim of the study was to investigate the effect of the immunosuppressant FK 506 (tacrolimus hydrate) on acute liver injury induced by Propionibacterium acnes and lipopolysaccharide (LPS). Acute liver injury was induced in male Wistar rats by injecting the animals with P. acnes (10 mg/rat), and administering LPS (10 g/rat) seven days later. One group was given FK 506 (1 mg/kg) 24 and 2 hr before administration of LPS, and the other group was given the same dose of saline. The 24-hr survival rate, serum alanine aminotransferase (ALT) concentration, and tumor necrosis factor (TNF) - mRNA and protein concentrations in the liver and spleen were then compared. Hepatic macrophages were also isolated from rats seven days after P. acnes injection, LPS, and FK 506 or saline were added to the culture supernatant, and TNF- production was studied. The 24-hr survival rate was 100% in the FK 506-treated group, in contrast with 16.6% in the saline group. Four hours after LPS injection, the serum ALT concentration was 755 ± 401 in the saline group versus 119 ± 42 units/ml (P < 0.01) in the FK 506-treated group. The serum TNF- concentration was lower in the FK 506-treated group (1419 ± 957 pg/ml) than in the saline group (9205 ± 2215) (P < 0.01). The mRNA and protein concentrations in the liver and spleen in the two groups did not differ significantly 1 hr after LPS injection but were significantly lower in the FK 506-treated group after 4 hr. FK 506 did not directly inhibit TNF- production by isolated cultured hepatic macrophages. FK 506 is unable to inhibit initial TNF- production by hepatic macrophages (or probably that by splenic macrophages either) stimulated by injection of LPS in P. acnes + LPS-induced acute liver injury. However, the immunosuppressant does limit hepatic damage by inhibiting subsequent aggravation of inflammation by the cytokine network.     

Effect of FK506 on the activation state of hepatic macrophages in Propionibacterium acnes-treated rats

Activated hepatic macrophages can provoke massive liver necrosis following endotoxin stimulation through microcirculatory disturbances due to sinusoidal fibrin deposition in rats pretreated with heat-killed Propionibacterium acnes. In these rats, FK506 (tachlorinus) administered 24 h before and at the time of endotoxin injection, significantly attenuated liver injury compared with the rats given no FK506. The effect of FK506 on hepatic macrophage activation and its action sites were studied in Propionibacterium acnes-treated rats. When rats received Propionibacterium acnes intravenously, hepatic-mRNA expression of interferon-γ-inducing factor and interleukin-2 and splenic-mRNA expression of interferon-γ were significantly increased compared with normal rats. Hepatic-mRNA expression of CD14, a receptor for lipopolysaccharide and its binding protein complex, was also increased preceding the expressions of the three cytokines in the liver and spleen. FK506 administration attenuated hepatic-mRNA expression of interleukin-2 and both superoxide anions as well as tumour necrosis factor-α production by hepatic macrophages, but did not change CD14-mRNA expression in Propionibacterium acnes-treated rats. It is suggested that a cytokine network through interferon-γ-inducing factor, interferon-γ and interleukin-2 may operate during activation of hepatic macrophages in rats treated with heat-killed Propionibacterium acnes, while CD14 expression on the cells may increase independently of this network. FK506 seems to attenuate such activation by suppressing hepatic interleukin-2 expression, without affecting CD14 expression on the cells.     

Failure of regeneration of the steatotic rat liver: disruption at two different levels in the regeneration pathway

Hepatic resection or transplantation in patients with fatty liver is associated with increased morbidity and mortality. The regenerative capacity of fatty livers after major tissue loss is unknown. Interleukin 6 (IL-6) is a potent inducer of hepatic regeneration in normal and ischemic livers. Therefore, we studied hepatic regeneration at day 1, day 2, and day 4 in a model of 70% hepatectomy in obese and lean Zucker rats, and obese Zucker rats pretreated with recombinant interleukin 6 (rIL-6). The mitotic cycle in hepatocytes was investigated by 4 different markers of regeneration representing distinct phases of mitosis (proliferating cell nuclear antigen [PCNA] = G(1) phase, bromodeoxy uridine [BrdU] = S phase, mitotic index, and regenerated liver weight = M phase). Obese Zucker rats had significantly decreased regenerative capacity compared with lean Zucker rats (PCNA, BrdU, mitotic index, regenerated liver weight) at days 1 and 2 after surgery. Four days after resection fatty animals showed an increase in the mitotic index indicating a delay of regeneration in steatotic livers. Animal survival after 70% hepatectomy was significantly decreased in obese rats compared with lean animals. Pretreatment of obese animals with rIL-6 normalized PCNA expression (G(1) phase) in steatotic hepatocytes but failed to increase DNA synthesis (BrdU, S phase), mitosis (mitotic index and regenerated liver weight, M phase), and animal survival. These results indicate major impairment of hepatic regeneration in steatotic livers. Two different blockages of regeneration must be present, one rIL-6 sensitive, at the level of IL-6 or upstream, and a second, rIL-6 resistant, at the level of G(1)/S-phase transition.     

The role of mitogen-activated protein kinases and the participation of intestinal congestion in total hepatic ischemia-reperfusion injury

BACKGROUND/AIMS: The mitogen-activated protein kinase (MAPK) pathways are comprised of key regulatory proteins that control the cellular responses to both proliferation and stress signals. This study was performed to examine the degree of liver damage and MAPK activation induced by ischemia of varying durations, and the association between intestinal congestion and liver dysfunction after hepatic ischemia-reperfusion injury. METHODOLOGY: Male Sprague-Dawley rats were divided into five groups: sham-operated controls (no hepatic ischemia); 15, 30, or 45 min of total hepatic ischemia; or 45 min of total hepatic ischemia with a portosystemic shunt. Serum levels of aspartate aminotransferase, alanine aminotransferase, lactate dehydrogenase, interleukin-1beta and tumor necrosis factor-alpha, as well as liver tissue blood flow were measured. Liver was also sampled for MAPK analysis and histopathological examination. RESULTS: Total hepatic ischemia for over 30 min, with intestinal congestion, caused severe liver damage and an inflammatory cytokine response. A portosystemic shunt attenuated ischemia-reperfusion injury and inhibited inflammatory cytokine expression. Extracellular signal-regulated kinase was markedly phosphorylated in all groups other than the sham-operated group. p38 MAPK and c-Jun N-terminal kinase were highly phosphorylated in all groups receiving 30 min or more of ischemia. CONCLUSIONS: Prolonged warm total hepatic ischemia-reperfusion injury is associated with small intestinal congestion; a portosystemic shunt reduces liver damage by inhibiting inflammatory cytokine expression. MAPKs are markedly phosphorylated after reperfusion.     

Ischemia impairs liver regeneration after major tissue loss in rodents: protective effects of interleukin-6.

The effects of ischemia on the regenerative capacity of the liver after major tissue loss remain unclear. Interleukin-6 (IL-6) has been shown to confer protection in models of normothermic ischemia and reperfusion injury and to initiate hepatocyte proliferation after major hepatectomy. Therefore, we investigated the effects of ischemia on the regenerative capacity of the liver and evaluated the role of IL-6 in reducing reperfusion injury and enhancing hepatic proliferation in models combining ischemia and major hepatectomy. Rats subjected to 70% hepatectomy and 30 minutes of hepatic ischemia showed significantly reduced regenerative capacity (mitotic index, proliferating cell nuclear antigen, and regenerated liver weight) when compared with animals subjected to hepatectomy alone. Pretreatment of animals subjected to hepatectomy and ischemia with recombinant interleukin-6 (rIL-6) completely restored each parameter of regeneration to levels comparable with those of animals subjected to hepatectomy only. Similar results were obtained in IL-6 deficient (IL-6(-/-)) mice. IL-6(-/-) mice exposed to ischemia and hepatectomy showed impaired hepatic regeneration when compared with wild-type mice subjected to the same experimental conditions. The use of rIL-6 completely corrected each parameter of regeneration showing the specificity of IL-6 in this type of injury. The impact of IL-6 on animal survival was studied in a model combining 45 minutes of ischemia and 68% hepatectomy. Five of 7 (71%) animals pretreated with rIL-6 survived permanently, whereas all control animals died within 3 days of surgery (P =.02, Fisher's exact test). In conclusion, the study shows that ischemia dramatically impairs the regenerative capacity of the liver. IL-6 appears to be a key protective molecule in reducing injury and promoting regeneration following combined ischemia and major tissue loss.     

Protective Effect of FK506 on Myocardial Ischemia/Reperfusion Injury by Suppression of CaN and ASK1 Signaling Circuitry

We investigated protective effect of FK506 on rat hearts subjected to ischemia/reperfusion (I/R) injury by regulating CaN and ASK1. Wistar rats were divided into four groups: Ischemia/reperfusion group (I/R), FK506 + Ischemia/reperfusion group (FK506-I/R), sham group, and FK506 + sham group (FK506-sham). Ischemia/reperfusion was achieved by occluding left coronary artery for 30 min and subsequently reperfusing for 120 min. FK506 was administered 15 min before ischemia. Rats in sham group and FK506-sham group were operated only by placing a ligature around the coronary artery, and the blood supply was not blocked. I/R group showed a rapid increase in TUNEL-positive cells and high risks of histopathological changes in damaged cardiac tissues. FK506 reduced the infarct size and inhibited the activation of CaN enzyme in FK506-I/R group. Increase in Bcl-2/Bax ratio in FK506-IR group indicated that FK506 protected myocardium from apoptosis induced by IR. The activity of CaN and ASK1 protein level decreased significantly after I/R injury in FK506-treated I/R heart. FK506 suppresses the activation of CaN and ASK1 through CaN-mediated apoptosis pathway, and ASK1 negatively regulates CaN activity. Suppression of CaN and ASK1 signaling circuitry are involved in protective effect of FK506 on rat myocardium I/R injury.     

Ischemic preconditioning improves liver regeneration by sustaining energy metabolism after partial hepatectomy under ischemia in rats.

BACKGROUND: The protective effect of ischemic preconditioning (IPC) has been reported on improvement of survival, reduction of liver necrosis and enhancement of the regenerative capacity of hepatocytes after partial hepatectomy. This study was undertaken to confirm that IPC has a significant impact on regeneration of hepatocytes after partial hepatectomy in ischemically damaged liver. In addition, we sought to examine the role of adenine nucleotides in this process. METHODS: Wistar rats were subjected to 60 min of total hepatic ischemia, followed by 70% hepatectomy. The animals were subdivided into an IPC (10/15 min) group and a non-IPC (control) group. Liver function tests and arginase activity were analyzed. Hepatic adenosine triphosphate (ATP), adenosine diphosphate and adenosine monophosphate were measured using gradient high-performance liquid chromatography. The liver regeneration was identified using relative liver weight and proliferating cell nuclear antigen (PCNA) labeling index. RESULTS: IPC treatment improved serum liver enzymes and tissue arginase activity (P<0.05) when compared with the control group. The preconditioned livers were associated with upregulation of ATP expression and also increased tissue energy charge. Regenerated liver weight in the IPC group was significantly higher than in the control group (P<0.05). The PCNA labeling index in the remnant livers in the IPC group was also significantly increased at 24 and 48 h after partial hepatectomy (P<0.05). CONCLUSION: These results suggest that IPC-augmented liver regeneration after hepatectomy, probably due to the stabilization of energy metabolism in rats.     

Interaction of L-arginine-methyl ester and Sonic hedgehog in liver ischemia-reperfusion injury in the rats

AIM： To investigate the role of Sonic hedgehog （Shh） on the course of liver ischemia and reperfusion （I/R） in rats, and the interaction between treatment with nitric oxide donor L-Arginine-methyl ester （L-Arg） and up-regulation of Shh expression.
METHODS： A total of 30 male Sprague-Dawley rats weighing 220-240 g were used in this study. Shamcontrol group （G1, n = 10）： a sham operation was performed （except for liver I/R）. I/R-untreated group （G2, n = 10）： rats underwent liver ischemia for 1 h followed by reperfusion for 45 min. I/R-L-Arg group （G3, n = 10）： after performing the same surgical procedure as in group 2, animals were treated with L-Arg. Liver tissues were taken for determination of malondialdehyde （MDA） levels, and biochemical and histological evaluations were made.
RESULTS： Plasma alanine aminotransferase （ALT）, aspartate aminotransferase （AS-T）, lactate dehydrogenase （LDH） and T-glutamyltranspeptidase （GGT） activities were higher in group 2 than in group 3. MDA values and the hepatic injury score decreased in the L-Arg treated group compared to the I/R-untreated group. In group 2, the hepatoo/tes were swollen with marked vacuolization. Group 3 rats showed well-preserved liver parenchyma, with hepatocytes extending from the central vein. The morphology of the hepatocytes and the sinusoidal structures was normal, without any signs of congestion. Mild Shh positive immunostaining was detected in group 2 animals. The expression of immunoreactive cells was increased markedly in liver tissue from I/R-L-Arg rats.
CONCLUSION： Our findings suggest that Shh molecules are critical factors in the pathophysiology of inflammatory liver injury induced by I/R. In addition, NO plays an important role in the immunohistochemical expression of these molecules.     

Pretreatment with FK506 up-regulates insulin receptors in regenerating rat liver

This report examines the effect of FK506 pretreatment on liver insulin receptor expression in partially (70%) hepatectomized rats. FK506 pretreatment led to an increased insulin receptor number 24 hours after hepatectomy, detected by means of insulin binding and cross-linking procedures. This increase was related to enhanced insulin receptor expression determined by in vitro mRNA translation and Western blot techniques. We also tested the functionality of the expressed insulin receptors by [(3)H] thymidine incorporation into DNA in insulin-stimulated hepatocytes. The results show that FK506 pretreatment elicits an increase in the amount of insulin receptor alpha-subunits as measured by Western blot. Maximum alpha-subunit expression recorded 24 hours after surgery was preceded by increased insulin receptor mRNA levels, which were detected 6 hours after hepatectomy. Moreover, in FK506-pretreated rat hepatocytes, obtained from remnant livers 24 hours after partial hepatectomy (PH), the increase in insulin receptor number was associated with improved sensitivity to the hormone. However, in both experimental groups (FK506-pretreated and nonpretreated rats), the sensitivity of hepatocytes toward epidermal growth factor (EGF) showed no significant change, which suggests a specific effect of FK506 on insulin receptor expression. In conclusion, our findings suggest that FK506 pretreatment induces insulin receptor expression in regenerating rat liver and promotes liver regeneration in hepatectomized rats.     

Hepatic tissue oxygenation as a predictive indicator of ischemia-reperfusion liver injury.

The purpose of this study was to determine whether hepatic tissue oxygenation after ischemia-reperfusion procedures is an indicator for later liver injury. Partial ischemia in the liver was induced by ligating the left pedicles. Rats were divided into two groups according to duration of ischemia: group A (30-min ischemia) and group B (60-min ischemia). Indices of blood oxygenation and blood volume in regional hepatic tissue, serum ALT levels and histological appearance of livers were evaluated. Twenty-four hours after ischemia and reflow, all rats in group A were alive, whereas only 67% survived in group B. Blood-oxygenation index and blood-volume index in group A rats rebounded quickly after reperfusion. In group B, blood-oxygenation index and blood-volume index remained significantly lower than in group A after reperfusion. Serum ALT levels at 60 and 120 min after reperfusion in group B were significantly higher than those in group A. Blood-oxygenation index measured at 5 and 60 min of reperfusion showed significant correlation with serum ALT levels at 120 min of reperfusion. When the percentage recovery of blood-oxygenation index at 5 and 60 min after reperfusion was more than 75%, all rats survived. No obvious signs of hepatocellular degeneration were observed histologically 5 min after reperfusion; however, substantial hepatocellular degeneration had occurred at 120 min of reperfusion in groups A and B. These data indicate that a decline in hepatic tissue oxygenation during the early phase of reperfusion (even when no obvious hepatocellular degeneration has been observed) can be a predictor of subsequent liver injury and prognosis.     

Erythropoietin promotes hepatic regeneration after extended liver resection in rats

Background and Aim:  It has been proven in various animal studies that recombinant human erythropoietin (rHuEPO) protects renal, cardiac and neuronal, as well as hepatic, tissue from ischemia, and promotes regeneration of adult central nervous system neurons. To date, no data are available as to whether rHuEPO has the ability to stimulate liver regeneration after liver resection.
Methods:  Rats undergoing 70% or 90% hepatectomy received an intraportalvenous administration (i.p.) of rHuEPO prior to resection or a subcutaneous injection (s.c.) for 3 days postoperatively, control animals were treated with surgery and saline injection only. Regeneration capacity of remnant livers was studied over 7 days by histology and immunohistochemistry (Ki-67, proliferating cell nuclear antigen [PCNA]). Polymerase chain reaction was carried out to measure transforming growth factor β (TGF-β), hypoxia induced factor (HIF), signal transducing activator 3 and vascular endothelial growth factor.
Results:  Ten-day survival in rats undergoing 90% hepatectomy significantly increased in i.p.-pretreated animals. After 70% hepatectomy the mitotic index was significantly increased in both rHuEPO-treated groups. These data were confirmed by PCNA and Ki-67 expression, which was significantly increased in the treated groups 24 h and 2 days after liver resection. TGF-β and HIF mRNA both were upregulated in control animals 3 h after surgery.
Conclusion:  rHuEPO effectively increased liver regeneration in rats after 70% liver resection and enhanced survival after 90% hepatectomy. Thus, rHuEPO may increase the regenerative capacity after major hepatectomy.     

Energy metabolism and survival of liver grafts from non-heart-beating donor rats with warm ischemia injury

Introduction The quality of liver graft is a key factor for liver transplantation. Organs from non- heart-beating donors (NHBDs) seem to bean effective option to alleviate the problem of liver donor shortage.[1-3] However, the main obstacle to the use of livers from NHBDs is that warm ischemia injury to the liver is related to cardiac arrest.[4-6] Moreover, in liver transplantation, the allograft sustains inevitable cold ischemia in addition to re- warming injury during liver reperfusion. …     

Effect of nutritional status of the donor on the quality of hepatic graft. Value of restoration of glycogenic reserves of the donor]

Initial function of the graft is an essential factor for successful liver transplantation. The aim of this study was to evaluate the influence of the nutritional status of the donor on hepatic graft quality at reperfusion. Livers (n = 41) were taken from pigs normally fed or fasted for 24 h or fasted for 24 h and conditioned for 2 hours with a solution containing glucose, fructose and glutamine. The quality of liver grafts was evaluated using an original, blood-free isolated perfusion model, after 8 h cold storage, or after 15 min warm ischemia performed prior to harvesting. The hepatic concentration of glycogen and ATP, measured from in vivo biopsies, was decreased in fasted animals (P less than 0.05 vs fed) and restored by nutritional conditioning (P less than 0.05 vs fasted). At the time of reperfusion following 8 h cold ischemia, the liberation of aminotransferases and lactate dehydrogenase was elevated in livers coming from fasted animals (P less than 0.05 vs fed) and restored to fed levels after nutritional conditioning (P less than 0.01 vs fasted). After 15 min of warm ischemia, the bile secretion during the reperfusion period was decreased in the 24 h fasted livers (P less than 0.01 vs fed) and reestablished after nutritional conditioning (P less than 0.01 vs fasted). Perfusion of the donor liver, in the 2 h preceding harvest, with a solution of glucose plus neoglucogenic precursors enhances the quality of the liver graft at the time of reperfusion.(ABSTRACT TRUNCATED AT 250 WORDS)     

S-adenosylmethionine protects post-ischemic mitochondrial injury in rat liver

BACKGROUND/AIMS: S-adenosylmethionine (SAM) is a thiol-containing compound with known therapeutic affects on cholestasis and hepatotoxicity. The aim of this study was to investigate the effect of SAM on the prevention of mitochondrial injury induced by hepatic ischemia and reperfusion. METHODS/RESULTS: Rats were subjected to 60 min of hepatic ischemia and 1 and 5 h of reperfusion. 2 h prior to ischemia, the animals received either vehicle or SAM intraperitoneally. In the vehicle-treated ischemic animals, serum aspartate aminotransferase levels increased at 1 h and again at 5 h of reperfusion and were reduced by SAM pre-treatment. Similarly, mitochondrial lipid peroxidation was elevated in the vehicle-treated group, but this elevation was attenuated by SAM. In contrast, mitochondrial glutamate dehydrogenase activity and reduced glutathione concentration both decreased in the vehicle-treated group, and this decrease was also inhibited by SAM. Hepatic ATP levels in the vehicle-treated rats were found to be 42% lower 5 h after reperfusion, however, treatment with SAM elevated these ATP levels. SAM treatment increased the concentration of adenosine but inhibited the accumulation of hypoxanthine in the ischemic liver. CONCLUSION: SAM protects against mitochondrial injury, which prevents mitochondrial oxidant stress and improves ischemia-induced hepatic energy metabolism.     

Neutrophil-mediated liver injury during hepatic ischemia-reperfusion in rats

BACKGROUND: Neutrophil plays an important role in hepatic ischemia-reperfusion injury. We investigated neutrophil infiltration in liver tissue, Kupffer cells' role in neutrophil accumulation, and apoptosis and regeneration of hepatocytes in liver ischemia-reperfusion injury. METHODS: Vascular microclamps were placed across the pedicles of the median and left lateral lobes for 90 minutes after 30% hepatectomy with the resection of caudate, right lateral and quadrate lobes and papillary process. Gadolinium chloride (GdCl3) was used to destroy Kupffer cells. Neutrophil activity was inhibited with Urge-8, a monoclonal antibody against neutrophil produced in our laboratory. GdCl3 (10 mg/kg) and Urge-8 (50 mg/kg) were given intravenously in respective groups. Ischemia control, GdCl3 and Urge-8 groups were compared. RESULTS: Following hepatic reperfusion, serum interleukin-8 (IL-8) levels and hepatic neutrophil counts peaked at 3 hours, and peak concentrations of alanine aminotransferase (ALT) occurred at 6 hours. Animals of the control group showed increases in neutrophil infiltration in liver tissue, liver enzyme levels, and apoptosis index of hepatocytes and decreases in overall survival rate and proliferating cell nuclear antigen (PCNA) expression of hepatocytes. The survival rates and PCNA proportion of hepatocytes were higher and the levels of hepatic neutrophil infiltration, liver enzymes, and hepatocyte apoptosis after reperfusion were lower in the GdCl3 and Urge-8 groups than those in the ischemia control group. CONCLUSIONS: Blockades of Kupffer cells' activity and neutrophil infiltration by GdCl3 and Urge-8 eliminate neutrophil-mediated hepatic injury and enhance subsequent hepatic regeneration during liver ischemiareperfusion.     

Tacrolimus (FK 506) induced thrombotic thrombocytopenic purpura after ABO mismatched second liver transplantation: salvage with plasmapheresis and prostacyclin

We report the course of thrombotic thrombocytopenic purpura (TTP) in a patient receiving tacrolimus (FK506) immunosuppression for an ABO mismatched second liver graft. A Chinese woman with fulminant hepatitis-B reactivation failed a living-related orthotopic liver transplantation (OLT) due to portal vein thrombosis. An ABO mismatched cadaveric OLT (group A to O) was performed, with peri-operative plasmapheresis to reduce anti-A hemagglutinin titers. On day 30, she developed fever, hemolysis, thrombocytopenia and neurologic dulling. Prominent microangiopathic features in peripheral blood film, and characteristic brain lesions on magnetic resonance imaging confirmed TTP. She responded initially to intensive plasmapheresis with cryosupernatant replacement, and withdrawal of FK506. An attempted reintroduction of FK506 for threatened rejection led to TTP exacerbation. This was controlled with prolonged plasmapheresis and a ten-day infusion of prostacyclin. Immunosuppression was changed to mycophenolate mofetil. By day 53, the peripheral film and lactate dehydrogenase level had returned to baseline and plasmapheresis was stopped.