Attenuation of graft injury in porcine liver transplantation from non-heart beating donor by FR167653

BACKGROUND/AIMS: Orthotopic liver transplantation (OLTx) from non-heart beating donor (NHBD) often involves hepatic warm ischemia and reperfusion injury which is triggered by the inflammatory cytokines. This study was carried out to investigate whether a newly synthesized cytokine suppressive anti-inflammatory agent, FR167653, attenuates graft injury in OLTx from NHBD. METHODOLOGY: Porcine OLTx from NHBD was performed. No-heart beating time was scheduled to be 60 minutes. Animals were divided into two groups: no treatment control (CT) group (n=5), and FR167653 treated (FR) group (n=5), in which FR167653 was administered intravenously before the aortic cross clamp in the donor, and before and after the hepatic allograft reperfusion in the recipient continuously. RESULTS: Four out of five pigs died within 24 hours and one on postoperative day 1 from graft liver failure in the CT group, while two pigs died on day 3, and three survived more than 7 days in the FR group (p<0.05). Microcirculatory disturbance was attenuated, liver injury was lessened, and ATP resynthesis was enhanced in the FR group. Additionally, FR167653 inhibited neutrophils infiltration in the liver tissue, and suppressed release of inflammatory cytokines after OLTx from NHBD. CONCLUSIONS: The treatments with FR167653 successfully prevented graft injury after OLTx from NHBD by means of improvement of liver microcirculation, and attenuation of neutrophils activation. The inhibitory effect of FR167653 on the release of inflammatory cytokines played an important role in the liver graft protection.     

Tumor necrosis factor suppression and microcirculatory disturbance amelioration in ischemia/reperfusion injury of rat liver after ischemic preconditioning

BACKGROUND: Brief periods of hepatic ischemia produce immediate tolerance for subsequent prolonged ischemia. Although the beneficial effect of this ischemic preconditioning is recognized, the mechanism itself remains poorly understood. METHODS: Male Wistar rats were divided into two groups: a control group that was subjected to 30 min of ischemia + following reperfusion, and an ischemic preconditioning group that was subjected to 5 min of ischemia + 5 min of reperfusion + 30 min of ischemia + following reperfusion. By using this model, hepatic damage, microcirculatory disturbances, and tumor necrosis factor-alpha protein production and mRNA expression were analyzed during the course of reperfusion in both groups. For the hepatic damage evaluations, hepatic enzyme levels, histology, apoptosis analysis, and intravital microfluorography for dead cells were examined. For the microcirculatory disturbance analysis, an adhesion molecule and intravital microfluorography for endothelial-adherent leukocytes were examined. RESULTS: In the ischemic preconditioning group, ischemia/reperfusion injuries (shown by hepatic enzymes elevation, histological degeneration, and increases in the number of apoptotic cells and microfluorographic dead cells) were markedly reduced. Moreover, microcirculatory disturbances represented by intercellular adhesion molecule-1 expression and leukocyte adhesion on the endothelium were ameliorated. Tumor necrosis factor-alpha protein production and mRNA expression were also suppressed in the ischemic preconditioning group. CONCLUSION: The suppression of tumor necrosis factor-alpha and the subsequent amelioration of microcirculatory disturbances were observed, suggesting that the mechanism underlying the protective effect of ischemic preconditioning in hepatic ischemia/reperfusion injuries may involve tumor necrosis factor-alpha and microcirculatory regulation.     

The effect of FR167653 in a canine total hepatic vascular exclusion model

BACKGROUND/AIMS: Though liver grafts from non-heart-beating donors are now attracting much attention, these grafts inevitably suffer from severe warm ischemia. The aim of this study was to evaluate the effect of TNF-alpha and IL-1 suppression on warm ischemia-reperfusion injury in a canine total hepatic vascular exclusion model. METHODOLOGY: Warm ischemia was induced by 1-h total hepatic vascular exclusion with active splenofemuro-juglar bypass. Animals were divided into two groups. FR167653 (1 mg/kg/hr) was administered via the portal vein from 30 min prior to ischemia until 2 h after reperfusion to the FR group (n = 7), and a vehicle was administered to the control group (n = 7). The serum alanine aminotransferase, aspartate amino-transferase, lactate dehydrogenase, and hyaluronic acid levels were measured. Hepatic tissue blood flow was also measured. Liver specimens were harvested for histological study, and polymorphonuclear neutrophils were counted. RESULTS: Serum liver enzymes were significantly (p < 0.05) lower, and hepatic tissue blood flow was kept significantly (p < 0.05) better in the FR group than in the control. Histological tissue damage was mild, and polymorphonuclear neutrophil infiltration was significantly (p < 0.05) lower in the FR group than in the control group. CONCLUSIONS: FR167653 provides protective effects on hepatic warm ischemic injury in a canine total hepatic vascular exclusion model.     

Induction of type 1 plasminogen activator inhibitor in human liver ischemia and reperfusion

BACKGROUND/AIMS: The detailed role of type 1 plasminogen activator inhibitor (PAI-1) in liver with ischemia reperfusion injury remains unclear. The aim of the present study was to examine this mechanism, focusing on inflammatory cytokines. METHODS: Eighteen patients who underwent partial hepatectomy (PH) for metastatic liver tumors using only Pringle's maneuver were enrolled in the study. Peripheral blood was taken perioperatively and PAI-1, tissue type plasminogen activator (tPA), plasma aspartate aminotransferase (AST) and cytokine levels were measured. Two liver specimens were taken from each patient, one before ischemia and the other after PH, for detection of mRNA of PAI-1, tPA, tumor growth factor (TGF)-beta1, interleukin-1beta and tumor necrosis factor-a. Immunohistochemistry and Western blotting were performed to detect PAI-1 protein in the liver. RESULTS: The average plasma PAI-1 antigen level reached a maximum after the final clamp (121.6+/-5.9 ng/ml). The average PAI-1 level in hepatic veins (140.4+/-6.3 ng/ml) after the last Pringle's maneuver was higher than that in peripheral veins (p<0.0001). A correlation was observed between the ratio of the corrected fluorescent activity of PAI-1 before and after ischemia and TGF-beta1 mRNA levels in the liver after PH (p=0.003). PAI-1 protein could be detected in parenchymal and non-parenchymal cells of the liver obtained after ischemia reperfusion injury. CONCLUSIONS: PAI-1 was produced in human livers after ischemia reperfusion injury provoked by Pringle's maneuver, giving valuable information regarding the degree of warm ischemic damage.     

Effect of FR167653 on Small Bowel Ischemia-Reperfusion Injury in Dogs

IL-1 and TNF- are known to be pleiotropiccytokines associated with various inflammatoryconditions such as small intestinal injury afterischemia-reperfusion. FR167653 has been characterized asa potent suppressant of IL-1 and TNF-production. The effect of FR167653 on intestinalreperfusion injury was investigated in a warm ischemiamodel of the canine gut. Sixteen mongrel dogs weredivided into two groups: a control group and a FR groupto which FR167653 was administered. Both the superiormesenteric artery and vein were clamped for 2 hr.Arterial pH, hepatic venous hemoglobin oxygensaturation, intramucosal pH, and the survival rate werewell maintained in the FR group in comparison with thecontrol group after reperfusion. FR167653 inhibited theexpression of IL-1 mRNA. Histologically,ischemia-reperfusion injury was more severe in the control groupthan the FR group. This study suggests that FR167653inhibits proinflammatory cytokines and amelioratesischemia-reperfusion injury of the smallintestine.     

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.     

Effect of notoginsenoside R1 on hepatic microcirculation disturbance induced by gut ischemia and reperfusion

AIM： To assess the effect of notoginsenoside R1 on hepatic microcirculatory disturbance induced by gut ischemia/reperfusion （I/R） in mice. METHODS： The superior mesenteric artery （SMA） of C57/BL mice was ligated for 15 min to induce gut ischemia followed by 30-rain reperfusion. In another set of experiments, R1 was continuously infused （10 mg/kg per hour） from 10 min before I/R until the end of the investigation to study the influence of R1 on hepatic microcirculatory disturbance induced by gut I/R. Hepatic microcirculation was observed by inverted microscopy, and the vascular diameter, red blood cell （RBC） velocity and sinusoid perfusion were estimated. Leukocyte rolling and adhesion were observed under a laser confocal microscope. Thirty and 60 min after reperfusion, lactate dehydrogenase （LDH）, alanine aminotransferase （ALl＇） and aspartate transaminase （AST） in peripheral blood were determined. The expression of adhesion molecules CD11b/CD18 in neutrophils and tumor necrosis factor- alpha （TNF-α）, interleukin-6 （IL-6） and monocyte chemotactic protein-1 （MCP-1） in plasma were evaluated by flow Oltometry. E-selectin and intercellular adhesion molecule-1 （ICAM-1） in hepatic tissue were examined by immunofluorescence.RESULTS： After gut I/R, the diameters of terminal portal venules and central veins, RBC velocity and the number of perfused sinusoids were decreased, while the leukocyte rolling and adhesion, the expression of E-selectin in hepatic vessels and CD18 in neutrophils, IL-6, MCP-1, LDH, ALT and AST were increased. R1 treatment attenuated these alterations except for IL-6 and MCP-1. CONCLUSION： R1 prevents I/R-induced hepatic microcirculation disturbance and hepatocyte injury, The effect of R1 is related to its inhibition of leukocyte rolling and adhesion by inhibiting the expression of E-selectin in endothelium and CD18 in neutrophils.     

FR167653, a p38 mitogen-activated protein kinase inhibitor, aggravates experimental colitis in mice

AIM： To investigate the effects of FR167653 on the development of dextran sulfate sodium （DSS）-induced colitis in mice. METHODS： BALB/c mice were fed rodent chow containing 3.5% （wt/wt） DSS. The recipient mice underwent intra-peritoneal injection of vehicles or FR167653 （30 mg/kg per day）. The mice were sacrificed on day 14, and the degree of colitis was assessed. Immunohistochemical analyses for CD4^＋ T cell and F4/80^＋ macrophage infiltration were also performed. Mucosal cytokine expression was analyzed by RT-PCR. RESULTS： The body weight loss was more apparent in the FR167653-treated DSS mice than in the vehicletreated DSS mice. The colon length was shorter in the FR167653-treated DSS mice than in the vehicle-treated DSS mice. Disease activity index and histological colitis score were significantly higher in FR167653- than in vehicle-treated DSS animals. Microscopically, mucosal edema, cellular infiltration （CD4 T cells and F4/80 macrophages）, and the disruption of the epithelium were much more severe in FR167653-treated mice than in controls. Mucosal mRNA expression for interleukin-1β （IL-1β） and tumor necrosis factor-α （TNF-α） were found to be markedly reduced in FR167653-treated DSS mice. CONCLUSION： Treatment with FR167653 aggravated DSS colitis in mice. This effect was accompanied by a reduction of mucosal IL-1β and TNF-α expression, suggesting a role of p38 mitogen-activated protein kinase （MAPK）-mediated proinflammatory cytokine induction in host defense mechanisms.     

A dual inhibitor of TNF-alpha and IL-1 mitigates liver and kidney dysfunction and improves survival in rat endotoxemia

BACKGROUND/AIMS: Endotoxin shock induces multiple organ dysfunction syndromes that are associated with a substantial increase in mortality. In this study, we evaluated the effect of FR167653, a potent suppressant of tumor necrosis factor-alpha (TNF-alpha) and interleukin-1 (IL-1) production, on lipopolysaccharide (LPS)-induced liver and kidney injury and lethality in rats. METHODOLOGY: Male Sprague-Dawley rats weighing from 200 to 270g received an injection of LPS. The FR group received an infusion of FR167653 at 0.2 mg/kg/hr, commencing 30 min prior to the LPS injection and continuing for 5.5 hr, while the control group received an infusion of a vehicle in the same fashion. Separate groups of animals were used for the survival study (n=5 each), and for blood sampling (n=5 each group, each time point). RESULTS: The FR group showed a significantly better survival rate'than the control group. Serum levels of GOT, Cr, and BUN were significantly lower in the FR group than in the control group. The elevation of TNF-alpha and IL-1beta at 2 hr after LPS administration was significantly lower in the FR group than in the control group. CONCLUSIONS: FR167653 administration is effective in decreasing serum TNF-alpha and IL-1beta levels and associated injury to liver and kidney caused by LPS-induced endotoxemia, as well as decreasing mortality.     

Enhanced inflammatory cytokine production at ischemia/reperfusion in human liver resection

BACKGROUND/AIMS: Clinical implications of acute reactant cytokine responses remain to be clarified in the setting of ischemia/reperfusion of human liver during liver resection and transplantation. METHODOLOGY: In serial samples of portal and systemic venous blood we examined acute inflammatory cytokine activities at the time points--before i), at the end of clamping ii), and one hour iii) and day 1 iv) after continuous hepatic inflow occlusion in 25 patients undergoing elective hepatectomy (15 major and 10 minor). Responses of tumor necrosis factor-alpha, interleukin-1 beta, interleukin-6 and interleukin-8 were compared with intraoperative parameters such as the duration of hepatic inflow occlusion and portal venous pressure during the occlusion, postoperative hepatocyte injury markers such as serum transaminases and bilirubin and also related complications. RESULTS: Portal interleukin-6 levels were significantly elevated during hepatic inflow occlusion, as compared with the systemic events (P < 0.02, at time point ii), but there were no differences in the interleukin-8 levels between the portal and systemic circulation. The increase in portal interleukin-6 levels during liver resection (time points, ii and iii) significantly correlated with the duration of hepatic inflow occlusion (48 +/- 9 min, mean +/- SD), portal venous pressure (500 +/- 127 mmH2O), and postoperative serum levels of transaminases (day 1; S-ALT, 705 +/- 1023 U/L; S-AST 892 +/- 1255 U/L) and maximum bilirubin (2.6 +/- 2.5 mg/dL). Interleukin-8 levels in the portal circulation showed no such correlation, but the levels in systemic blood showed significant positive relationships with the intra- and postoperative parameters. One patient who died had an enhanced generation of the cytokines in the presence of an elevated portal venous pressure. CONCLUSIONS: These observations suggest that overproduction of acute reactant cytokines (interleukin-6 from the portal system and interleukin-8 from the systemic circulation) in hepatic ischemia/reperfusion relates positively with postoperative hepatocyte injury in humans. We propose that hepatectomy done under a prolonged continuous inflow occlusion should be reconsidered when an enhanced generation of acute cytokines is anticipated, especially in case of a markedly high portal pressure during hepatic pedicle clamping.     

Protective effect of prostaglandin E1 against ischemia/reperfusion-induced liver injury: results of a prospective, randomized study in cirrhotic patients undergoing subsegmentectomy

Background/Aims: The cytoprotective effects of prostaglandin E1 on livers suffering from ischemia/reperfusion injury in the clinical setting are unproved. These effects were examined, focusing on inflammatory cytokine and nitric oxide metabolism.Methods: Twenty-four cirrhotic patients with hepatocellular carcinoma undergoing subsegmentectomy under ischemia induced only by Pringle's maneuver were divided into two groups (patients given prostaglandin E1 by injection and untreated controls) and postoperative results were compared. Peripheral blood was taken perioperatively and the plasma aminotransferase, cytokines and nitrate/nitrite levels of the two groups were compared. Two liver specimens were taken from each patient, one before ischemia and the other after hepatectomy, and the levels of inducible nitric oxide synthase and cytokine mRNAs and proteins were analyzed.Results: Although no apparent differences were recognized in postoperative complications or duration of postoperative hospital stay between the groups, the perioperative plasma aminotransferase level was significantly lower in the prostaglandin E1 group. Significant differences were also seen in interleukin-6 and nitrate plasma levels during the observation period and the interleukin-6 protein levels in the liver supernatants after hepatectomy in the two groups. In contrast, no significant differences were apparent between the interleukin-1 beta and tumor necrosis factor-alpha plasma levels of the two groups. The corrected fluorescence activities of interleukin-6 and inducible nitric oxide synthase mRNAs in the liver after hepatectomy correlated significantly. No interleukin-1 beta or tumor necrosis factor-alpha mRNAs or proteins were detected.Conclusions: Prostaglandin E1 exerted hepatoprotective effects on livers suffering from ischemia/reperfusion injury, and interleukin-6 might play an important role in these effects.     

FR167653, a potent suppressant of interleukin-1 and tumor necrosis factor-alpha production, ameliorates colonic lesions in experimentally induced acute colitis.

BACKGROUND: Interleukin-1 (IL-1) and tumor necrosis factor-alpha (TNF-alpha) are believed to play a significant role in the pathogenesis of inflammatory bowel disease (IBD). Interleukin-1 and TNF-alpha possess overlapping and synergetic activities inducing the production in cascade of other cytokines, adhesion molecules, arachidonic acid metabolites, as well as activating immune and non-immune cells. FR167653 (C24H18FN5O2-H2SO4-H2O) is a newly synthesized organic compound with a potent inhibitory effect on IL-1beta and TNF-alpha production. We hypothesized that the suppression of IL-1 and TNF-alpha induced by FR167653 could effectively attenuate experimentally induced colonic damage. METHODS: Colonic lesions were induced in male Sprague-Dawley rats (250-300 g) by intrarectal instillation of 4% acetic acid. The effect of FR167653 administration at 1.0, 1.5, 2.5 mg/kg per 6 h subcutaneously on acetic acid-induced colonic damage was assessed. The lesion area, microscopic findings, colonic and serum levels of TNF-alpha and IL-1beta were also evaluated. RESULTS: Treatment with FR167653 at 1.5 and 2.5 mg/kg per 6 h was able to ameliorate the gross macroscopic appearance of colonic lesions significantly, as well as ameliorate the lesion area induced by acetic acid. Colonic mucosal TNF-alpha and IL-1beta levels of rats treated with FR167653 showed significant decrease in a dose-dependent fashion compared with the control group. In the same manner, serum TNF-alpha of rats treated with FR167653 was significantly lower than that of respective controls. CONCLUSIONS: Subcutaneous administration of FR167653 was able to ameliorate the acute changes induced by acetic acid instillation in a dose-dependent manner. This is the first report to evaluate the dual inhibition of the production of IL-1 and TNF-alpha, offered by FR167653, in acute experimental colitis. Further studies are necessary to evaluate FR167653's efficacy and safety on long-term conditions.     

Expression of macrophage inflammatory protein-1α in Kupffer cells following liver ischemia or reperfusion injury in rats

AIM: To explore the expression of macrophage inflammatory protein-1α (MIP-1α) in Kupffer cells (KCs)following liver ischemia/reperfusion injury IRI in rats.METHODS: Forty male SD rats were divided randomly into five groups. A model of partial warm ischemia/reperfusion injury in the rat liver was established. KCs were isolated and incubated one hour, six hours, 12 h,and 24 h after the reperfusion. Tumor necrosis factor alpha (TNF-α) and interleukin-1beta (IL-1β) in the supernatants were measured by ELISA. MIP-1α in KCs was detected by immunocytochemical and RT-PCR.RESULTS: No or few MIP-1α protein and mRNA were expressed in the KCs of the control group. Its expression in the IRI group had a significant increase after the reperfusion (P ＜ 0.05), which was contrary to the control group.CONCLUSION: The active behavior of the MIP-1α gene in KCs following liver ischemia/reperfusion injury is assumed to be one of the major causes for the hepatic ischemia/reperfusion injury.     

Expression of macrophage inflammatory protein-1α in Kupffer cells following liver ischemia or reperfusion injury in rats

AIM: To explore the expression of macrophage inflammatory protein-1alpha (MIP-1alpha) in Kupffer cells (KCs) following liver ischemia/reperfusion injury IRI in rats. METHODS: Forty male SD rats were divided randomly into five groups. A model of partial warm ischemia/reperfusion injury in the rat liver was established. KCs were isolated and incubated one hour, six hours, 12 h, and 24 h after the reperfusion. Tumor necrosis factor alpha (TNF-alpha) and interleukin-1beta (IL-1beta) in the supernatants were measured by ELISA. MIP-1alpha in KCs was detected by immunocytochemical and RT-PCR. RESULTS: No or few MIP-1alpha protein and mRNA were expressed in the KCs of the control group. Its expression in the IRI group had a significant increase after the reperfusion (P < 0.05), which was contrary to the control group. CONCLUSION: The active behavior of the MIP-1alpha gene in KCs following liver ischemia/reperfusion injury is assumed to be one of the major causes for the hepatic ischemia/reperfusion injury.     

Glycine maintains mitochondrial activity and bile composition following warm liver ischemia-reperfusion injury

Background and Aim: Experimental studies have shown protective effect by the non‐essential amino acid glycine to liver ischemia‐reperfusion (I/R) injury but the mechanism of action is unknown. Methods: A rabbit model of hepatic lobar I/R was used. Three groups of animals (n = 6) were studied: Sham group (laparotomy alone), ischemia reperfusion (I/R) group (1 h of liver lobar ischemia and 6 h of reperfusion), and a glycine I/R group (intravenous glycine 5 mg/kg prior to the I/R protocol). Systemic and hepatic hemodynamics, degree of liver injury (bile flow, transaminases), hepatic microcirculation, mitochondrial activity (redox state of cytochrome oxidase), bile composition and cytokines (tumor necrosis factor‐α and interleukin‐8) were measured during the experiment. Results: Glycine administration increased portal blood flow, bile production, hepatic microcirculation and maintained cytochrome oxidase activity as compared with the I/R group during reperfusion. Glycine also reduced bile lactate surge and stimulated acetoacetate release in bile during reperfusion versus the I/R group. Cytokine levels (tumor necrosis factor‐α, interleukin‐8) and hepatocellular injury (aspartate aminotransferase and alanine aminotransferase) were significantly reduced by glycine administration. Conclusion: Intravenous glycine administration reduces liver warm I/R injury by reducing the systemic inflammatory response, and maintaining cellular energy production.     

Requirement for interleukin-12 in the pathogenesis of warm hepatic ischemia/reperfusion injury in mice

Hepatic ischemia and reperfusion causes neutrophil-dependent liver injury. Although the mechanisms of ischemia/reperfusion-induced liver neutrophil recruitment are somewhat understood, less is known regarding the early events that initiate the inflammatory injury. Using a murine model of partial hepatic ischemia and reperfusion, we evaluated the role of endogenous interleukin (IL)-12 in this inflammatory response. Hepatic ischemia for 90 minutes and reperfusion for up to 4 hours resulted in hepatocyte expression of IL-12. By 8 hours of reperfusion there were large increases in serum levels of interferon-gamma (IFNgamma) and tumor necrosis factor-alpha (TNFalpha). In addition, hepatic ischemia/reperfusion caused significant increases in liver neutrophil recruitment, hepatocellular injury, and liver edema, as defined by liver myeloperoxidase content, serum alanine aminotransferase, and liver wet to dry weight ratios, respectively. In mice treated with neutralizing antibody to IL-12 and in mice deficient in the IL-12 p40 gene, ischemia/reperfusion-induced increases in IFNgamma and TNFalpha were greatly diminished. These conditions also caused significant reductions in liver myeloperoxidase content and attenuated the parameters of liver injury. The data suggest that IL-12 is required for the full induction of injury after hepatic ischemia and reperfusion.     

Dynamical changing patterns of histological structure and ultrastructure of liver graft undergoing warm ischemia injury from non-heart-beating donor in rats

AIM: To investigate the histological and ultra-structural characteristics of liver graft during different of warm ischemia time (WIT) in rats and to predict the maximum limitation of liver graft to warm ischemia. METHODS: The rats were randomized into 7 groups undergoing warm ischemia injury for 0, 10, 15, 20, 30, 45 and 60 min, respectively. All specimens having undergone warm ischemia injury were investigated dynamically by light and electron microscopy, and histochemistry staining. After orthotopic liver transplantation (OLT), the recovery of morphology of liver grafts after 6, 24 and 48 h was observed. RESULTS: The donor liver from non-heart-beating donors (NHBD) underwent ischemia injury both in the warm ischemia period and in the reperfusion period. Morphological changes were positively related to warm ischemia injury in a time-dependent manner during the reperfusion period. The results demonstrated that different degrees of histocyte degeneration were observed when WIT was within 30 min, and became more severe with the prolongation of WIT, no obvious hepatocyte necrosis was noted in any specimen. In the group undergoing warm ischemia injury for 45 min, small focal necrosis occurred in the central area of hepatic lobule first. In the group undergoing warm ischemia injury for 60 min, patchy or diffused necrosis was observed and the area was gradually extended, while hepatic sinusoid endothe-lial cells were obviously swollen. Hepatic sinusoid was obstructed and microcirculation was in disorder. CONCLUSION: The rat liver graft undergoing warm ischemia injury is in the reversible stage when the WIT is within 30 min. The 45 min WIT may be a critical point of rat liver graft to endure warm ischemia injury. When the WIT is over 60 min, the damage is irreversible.     

Dynamical changing patterns of histological structure and ultrastructure of liver graft undergoing warm ischemia injury from non-heart-beating donor in rats

AIM: To investigate the histological and ultra-structural characteristics of liver graft during different of warm ischemia time (WIT) in rats and to predict the maximum limitation of liver graft to warm ischemia. METHODS: The rats were randomized into 7 groups undergoing warm ischemia injury for 0, 10, 15, 20, 30,45 and 60 min, respectively. All specimens having undergone warm ischemia injury were investigated dynamically by light and electron microscopy, and histochemistry staining. After orthotopic liver transplantation (OLT), the recovery of morphology of liver grafts after 6, 24 and 48 h was observed. RESULTS: The donor liver from non-heart-beating donors (NHBD) underwent ischemia injury both in the warm ischemia period and in the reperfusion period. Morphological changes were positively related to warm ischemia injury in a time-dependent manner during the reperfusion period. The results demonstrated that different degrees of histocyte degeneration were observed when WIT was within 30 min, and became more severe with the prolongation of WIT, no obvious hepatocyte necrosis was noted in any specimen. In the group undergolng warm ischemia injury for 45 min, small focal necrosis occurred in the central area of hepatic lobule first. In the group undergoing warm ischemia injury for 60 min, patchy or diffused necrosis was observed and the area was gradually extended, while hepatic sinusoid endothe lial cells were obviously swollen. Hepatic sinusoid was obstructed and microcirculation was in disorder. CONCLUSION: The rat liver graft undergoing warm ischemia injury is in the reversible stage when the WIT is within 30 min. The 45 min WIT may be a critical point of rat liver graft to endure warm ischemia injury. When the WIT is over 60 min, the damage is irreversible.