Kupffer cell-mediated inhibition of liver regeneration after combined hepatectomy and pancreatectomy

Recently, simultaneous hepatectomy and pancreatoduodenectomy has been performed for the treatment of some biliary tract cancers in Japan. Postoperative hepatic failure is a common and potentially fatal complication. The aim of this study was to examine the reduction in the rate of liver regeneration after 70% hepatectomy (Hx) alone or in combination with 70% pancreatectomy (HPx). Male Sprague-Dawley rats underwent hepatectomy or simultaneous hepatectomy and pancreatectomy. The ratio of liver weight to body weight, the labeling index of hepatocytes in vivo, and DNA synthesis of the hepatocytes and/or Kupffer cells in primary culture were analyzed. The ratio of liver weight to body weight and the labeling index in HPx rat were found to be significantly lower than those values in Hx rats. There were no significant differences in plasma alanine aminotransferase levels between the two groups. The inhibitory effect on DNA synthesis was observed with coculture of hepatocytes and Kupffer cells when the portal plasma obtained 1 hour after operation was added. We further observed that the conditioned medium of Kupffer cells stimulated by the addition of the portal plasma that was obtained 1 hour after HPx inhibited DNA synthesis of hepatocytes. This effect was abolished after incubation at 56° C for 30 minutes. These results strongly suggest the existence of a growth inhibitory factor in portal plasma after HPx. This heat-labile growth inhibitory factor was released from Kupffer cells and would appear to act on hepatocytes in a paracrine manner. Supported by the Kanae Foundation for Life and Sociomedical Science, Japan. Presented at the Thirty-Eighth Annual Meeting of The Society-for Surgery of the Alimentary Tract, Washington, D.C., May 11–14, 1997.     

Hepatic protein synthesis in the regenerating rat liver after hepatopancreatectomy

To evaluate the effects of hepatopancreatectomy on the regenerative process of the liver, the serum protein changes, hepatic protein synthesis (HPS), and bromodeoxyuridine (BrdU) labeling index were measured in rats. Sprague-Dawley rats were divided into four groups according to the type of resection: A simple laparotomy was performed in the sham group; 68% of the liver was excised in the Hx group; 45% of the pancreas was excised in the Px group; and 45% of the pancreas and 68% of the liver were excised simultaneously in the HPx group. Serum total protein and albumin levels were significantly lower in the HPx group compared to the other three groups on postoperative day (POD) 3 (P<0.05). HPS was markedly increased in the Hx and HPx groups. In the Hx group, it was significantly higher, peaking on POD 2, compared to the HPx group (P<0.05), while in the HPx group, it was significantly higher compared to the Hx group (P<0.05), peaking on POD 3. The BrdU labeling index, as a marker of DNA synthesis, was significantly suppressed in the HPx group on POD 1 compared to the Hx group (P<0.05). Thus, compared to hepatectomy alone, hepatopancreatectomy suppresses DNA synthesis, causing a delay in the increase of protein synthesis in the regenerating liver, resulting in a more marked decrease in the serum protein level.     

Morphological and functional changes after portal vein occlusion in rats

We investigated morphological and functional changes after portal vein occlusion in rats. Portal branches for the median and left lateral lobes were ligated, after which the lobes were examined micromorphologically. After embolization of the same branches, regenerative capacity was evaluated in normal livers and in livers with CCl₄-induced cirrhosis. Indocyanine green elimination, antithrombin III activity, and Kupffer cell density were also investigated. In another set of rats, the embolized lobes were resected 0, 2, 4, or 7 days after portal vein embolization (PVE), and endotoxin was injected intravenously 48h after each hepatectomy. In the ligated lobes, apoptotic hepatocytes were detected mainly around a widespread necrotic area on day 2, and among normal hepatocytes on day 7. In the nonembolized livers of control rats, increases were noted in liver weight, ornithine decarboxylase (ODC) activity, DNA synthesis, and mitosis of hepatocytes. In the cirrhotic livers, ODC activity was stimulated in a fashion similar to that seen in control liver, but DNA synthesis and weight change was delayed, although not significantly. On days 2, 4, 7, and 14 PVE, Kupffer cell density was about twice that seen in rats before PVE. Endotoxin-induced liver injury was slight if the rats had received PVE 4-7 days before the hepatectomy.     

Effect of portal branch ligation on liver regeneration in the rat

GOAL: The aim of this study was to assess liver regeneration after partial portal ligation. METHODS: 70% partial portal occlusion was obtained by ligation of the left portal vein branch. Total liver weight ratio were measured 96 hours after partial portal occlusion and in sham operated animals. The kinetics of hepatocytes division was evaluated by measuring the incorporation of 5-bromo-21-deoxyuridine into replicating cells at various time points by immunohistochemistry. RESULTS: Partial portal occlusion did not alter the total liver weight 96 hours after surgery. It resulted in atrophy of the ligated lobes and hypertrophy of the lobes with preserved portal flow. Hypertrophy was associated to an increase of the percentage of replicating hepatocytes. The replication rate was maximum at 28 hours with a peak at 12.5% and was prolonged beyond the 48th hour. CONCLUSIONS: Partial portal occlusion results in major and prolonged regeneration process in the liver lobes with preserved portal flow.     

Effect of portal hemodynamics on liver regeneration studied in a novel portohepatic shunt rat model

BACKGROUND: The role of portal hemodynamics on liver regeneration after partial hepatectomy is not fully understood. The aim of our study was to characterize the effects of portal hemodynamics using a novel rat model. METHODS: We established a rat model of a portohepatic shunt with a 70% hepatectomy (PHS model), in which the portal pressure remained stable during and after the 70% hepatectomy. To assess the effect of portal hemodynamics on liver injury and regeneration in the first 24 hours, we compared PHS rats with those with a simple 70% hepatectomy. RESULTS: Biochemical and histopathologic changes were similar between the 2 groups. Liver weight increased in the control, whereas it did not in the PHS group (P = .0021). Hepatocytes were enlarged in the control but not in the PHS group, although DNA synthesis was similar in both groups. Apoptotic hepatocytes increased markedly in PHS at 24 hours, whereas minimal apoptosis was noted throughout the course of the study in the control group. Hepatocyte growth factor increased similarly, except that it was not activated in PHS. CONCLUSIONS: Our results suggested that a portal hyperdynamic state early after a 70% hepatectomy was necessary for liver regeneration through activation of hepatocyte growth factor, promoting hepatocyte hypertrophy and avoiding apoptosis, while DNA synthesis in hepatocytes was independent of portal hemodynamics.     

Modulation of hepatocyte protein synthesis by endotoxin-activated Kupffer cells. III. Evidence for the role of a monokine similar to but not identical with interleukin-1.

The authors previously reported that unstimulated peritoneal macrophages and LPS stimulated Kupffer cell-rich nonparenchymal liver cells (NPC) can inhibit protein synthesis in cultured rat hepatocytes. Hepatocyte function was similarly altered by supernatants from LPS-triggered NPC. Secretory products of macrophages and Kupffer cells (monokines) are possible mediators in this model of cell-mediated modulation of hepatocyte function. In this article, supernatants from NPC capable of altering hepatocyte protein synthesis were found to contain significant amounts of one monokine, interleukin-1 (IL-1). The kinetics of the generation of the ability to inhibit protein synthesis and the appearance of IL-1 activity were roughly parallel for the first 24 hours. Exposure of hepatocytes to NPC supernatant and commercially available highly purified IL-1 resulted in similar response patterns with regard to onset of inhibition and progression of suppression after removal. Certain discrepancies cast doubt, however, on the likelihood that IL-1 is the mediator in this model of cell-mediated inhibition of hepatocyte protein synthesis. Commercial human IL-1 preparations did not always suppress protein synthesis in cultured rat hepatocytes. Furthermore, IL-1 activity was stable for several days but hepatocyte inhibition was lost. Unstimulated peritoneal macrophage supernatants containing IL-1 activity could not inhibit protein synthesis in hepatocytes. The evidence supports the idea that appropriately stimulated cells of monocyte-macrophage lineage (including Kupffer cells that lie in direct apposition to hepatocytes) could mediate hepatocyte malfunction by means of secreted monokines similar to, but not necessarily identical to, IL-1.     

大鼠烧伤后库普弗细胞在促炎细胞因子产生中的作用

目的　观察大鼠严重烧伤后早期 ,库普弗细胞在肿瘤坏死因子α(TNFα)、白细胞介素(IL) 1β、IL 6产生中的作用。方法　观察 (1)烧伤血清对体外培养的大鼠库普弗细胞分泌TNFα、IL 1β、IL 6的刺激作用 ;(2 )烧伤后大鼠库普弗细胞的细胞因子mRNA表达变化 ;(3)应用库普弗细胞特异性抑制剂三氯化钆后 ,烧伤大鼠血浆内细胞因子含量变化。　结果　烧伤血清能刺激库普弗细胞释放TNFα、IL 1β、IL 6 ;大鼠烧伤后库普弗细胞TNFα、IL 1β、IL 6mRNA表达量显著升高 ;预先抑制库普弗细胞的活性 ,烧伤后血浆TNFα、IL 1β、IL 6水平均显著降低 ,分别为烧伤组的 34.71%、36 99%、33.70 %。结论　库普弗细胞是大鼠烧伤后血浆中TNFα、IL 1β、IL 6的主要来源     

The influence of brain death on liver in rats

OBJECTIVE: Donor brain death produces functional and morphological changes in peripheral organs. We examined the influence of brain death on liver function. METHODS: Fifty rats were randomly divided into three groups: controls (C), sham-operated (E1), and brain-dead (E2). All rats underwent tracheotomy with assisted respiration. The sera of rats at 1 and 3 hours after brain death were tested for the levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), hyaluronic acid (HA), and endothelin-1 (ET-1). At the end of assisted respiration, liver samples were collected for ultrastructural observation. RESULTS: At 1 and 3 hours, the levels of ALT, AST, HA, and ET-1 in group E2 were significantly higher than those in groups C and E1 (P < .05). The levels of ALT, AST, HA, and ET1 at 3 hours were significantly higher than those at 1 hour (P < .05). Under the electronic microscope, Kupffer cells were activated, sinusoidal endothelial cells (SEC) denuded, fenestration widened, and hepatocytes under the SEC exposed in group E2. In group C and E1, Kupffer cells were not obviously activated and SEC were almost intact. CONCLUSIONS: Brain death damages hepatocytes and nonparenchymal cells in rat. Endothelin-1 and Kupffer cells play an important role in the process. The clearance of hyaluronic acid may provide reliable index to judge SEC function after brain death.     

Hepatocyte growth factor supply accelerates compensatory hypertrophy caused by portal branch ligation in normal and jaundiced rats.

BACKGROUND: Hepatocyte growth factor (HGF), first identified as the most potent mitogen for hepatocytes, significantly stimulates liver regeneration after hepatectomy. In this report, we examined whether HGF is also useful in accelerating compensatory hypertrophy caused by portal branch ligation in normal and jaundiced rats. MATERIALS AND METHODS: Normal and reversible obstructive jaundiced rats underwent portal ligation of the left lateral and median branches, which supply approximately 70% of the total volume of the liver. Simultaneously, the animals were continuously treated with either recombinant human HGF (rhHGF) or vehicle alone via an intraperitoneally implanted osmotic pump. Two and four days after portal ligation, the degree of compensatory hypertrophy in unoccluded lobes was examined by measuring the wet weight ratios of the unoccluded lobes to the whole liver and the 5-bromo-2'-deoxyuridine labeling index of hepatocytes in each group. RESULTS: The HGF treatment significantly increased the wet weight ratios and the DNA synthesis in nonoccluded lobes 2 and 4 days after portal ligation in both normal and jaundiced rats. Moreover, rhHGF supply promptly decreased serum total bilirubin level in jaundiced rats. CONCLUSIONS: Continuous rhHGF administration not only accelerates compensatory hypertrophy in normal and jaundiced rats but also ameliorates hyperbilirubinemia in jaundiced rats.     

肝切除术后肝再生对大鼠结肠癌肝转移灶生长的影响

目的 探讨肝再牛进程触发大鼠结肠痛肝转移残肝内隐性转移灶进展的发生机制.方法 采用肝包膜下种植建立结肠癌肝转移大鼠模型,随机分为假手术组、37%肝切除组和70%肝切除组;采用腹膜后注射建市结肠癌腹膜后转移模型,随机分为假手术组和70%肝切除组.手术后3周处死动物,测定肝内转移瘤量、再生肝重及腹膜后瘤结节重.在含有肝切除后24 h和14 d的门静脉血清培养基中进行结肠癌细胞Lovo体外培养,5.溴脱氧尿核苷(5-BrdU)DNA掺入法检测细胞增殖反应.结果 手术切除明显促进70%肝切除组肝内残留癌牛长(P<0.05),对37%肝切除组肝内残留癌和结肠癌腹膜后转移瘤牛长无促进作用(P>0.05);肝切后24 h门静脉血清组5-BrdU DNA掺人率从第72小时开始增加,至第120小时呈持续增加趋势(P<0.05);肝切后14 d门静脉血清对结肠癌细胞生长无明显刺激作用(P>0.05).结论 结肠癌肝转移切除术后可诱发肝内微小残留灶的进展,并不通过血液循环全身性释放,对肝外转移瘤并不发挥作用.肝切除范围与诱发肿瘤生长有关,只有肝切除达到一定程度时,才足以刺激肿瘤生长.     

Autonomic Nervous System and Gut-derived Endotoxin: Involvement in Activation of Kupffer Cells after In Situ Organ Manipulation

Gentle in situ organ manipulation rapidly causes disturbances in the hepatic microcirculation, hypoxia, and activation of Kupffer cells. Because the mechanisms of Kupffer cell activation after organ manipulation remain unclear, the possible role of the autonomic nervous system and gut-derived endotoxin were assessed. To mimic what occurs with major abdominal surgery, livers from female Sprague-Dawley rats (200–230 g) underwent minimal dissection for 12 minutes and were manipulated gently or were left alone for 13 subsequent minutes. Kupffer cells were activated 2 hours after manipulation, reflected by a significant increase in intracellular calcium ([Ca²⁺]_i) from about 90 nM in unmanipulated controls to more than 180 nM in response to lipopolysaccharide (LPS 100 ng/ml). Furthermore, Kupffer cells from manipulated rats produced about threefold more tumor necrosis factor-α after LPS (100 ng/ml) than did the unmanipulated controls. Moreover, O₂ uptake of ex situ perfused liver was increased from about 110 μmol/g/hr in unmanipulated controls to more than 160 μmol/g/hr 2 hours after organ manipulation. Binding of pimonidazole (120 mg/kg IV), a 2-nitroimidazole hypoxia marker given 2 hours after manipulation, increased about 2.5-fold, and hepatic glycogen was depleted. Two hours after organ manipulation gut permeability to horseradish peroxidase was elevated and endotoxin in the portal venous blood was increased twofold. Microsurgical hepatic denervation, ganglionic blockade, adrenalectomy, and antibiotics to sterilize the gut before manipulation prevented activation of Kupffer cells by organ manipulation. Hexamethonium and adrenalectomy prevented increases in gut permeability caused by manipulation. Although antibiotics blunted the increase in portal venous endotoxin significantly, there was no effect on gut permeability. These data indicate for the first time that both the autonomic nervous system and gut-derived endotoxin are involved in activation of Kupffer cells after organ manipulation.     

Severe steatosis increases hepatocellular injury and impairs liver regeneration in a rat model of partial hepatectomy

OBJECTIVE: The aim of this study was to assess the influence of severe steatosis with inflammation on hepatocellular recovery after 70% hepatectomy in a rat model of diet-induced steatosis. BACKGROUND: Patients with steatosis have an increased risk of inflammatory complications after liver resection. This might be attributable to Kupffer cell-mediated inflammation in steatotic livers causing progressive injury. METHODS: Male Wistar rats were fed a standard methionine- and choline-deficient diet for 1 or 5 weeks. A 70% partial hepatectomy (PH) was performed, after which rats were killed at 24, 48, or 72 hours. The extent of steatosis and inflammation was determined by assessment of hepatic triglycerides, cytokine content, and histopathology. Outcome parameters were: liver regeneration (MIB-5 proliferation rate, mitotic index, and regenerating liver mass), hepatocellular injury (plasma aminotransferases, lipid peroxidation, histopathology, and apoptosis), Kupffer cell-mediated proinflammatory response (TNF-alpha, IL-1beta, IL-6, IL-10 in plasma and liver) and antioxidant content (total glutathione). RESULTS: Methionine- and choline-deficient diet induced uncomplicated steatosis after 1 week (<30% hepatocytes affected without inflammation) and severe steatosis after 5 weeks (>60% hepatocytes affected, including prominent inflammation) as confirmed by histopathology. After PH, liver regeneration was impaired at all time points in the severe steatosis group as compared with the mild and control groups (P < 0.05). Hepatocellular injury was significantly increased in the severe steatosis group at all time points (P < 0.05). Kupffer cell-mediated inflammatory responses were aggravated in the severe steatosis group along with decreased antioxidant content (P < 0.05). Necrosis was the main type of cell death in severe steatotic livers compared with mainly apoptotic cell death in mild steatotic and normal livers. CONCLUSION: Steatosis with prominent inflammation impaired liver regeneration probably because of increased hepatocellular lipid peroxidation and damage in concert with Kupffer cell-mediated proinflammatory responses. These results suggest an increased risk of performing extensive liver resection in the presence of severe steatosis.     

Significance of sonic hedgehog signaling after massive hepatectomy in a rat

Purpose

To clarify the functional involvement of hedgehog signaling, especially sonic hedgehog (Shh) and glioma-associated oncogene (Gli)-1 which are known to play an important role in embryonic development and cancer, in the regeneration of a hepatectomized rat liver.

Methods

Six-week-old male Wistar rats were subjected to 70 or 90 % hepatectomy (Hx). Animals were killed at 24, 48 and 72 h after Hx. The liver/body weight ratio was measured as an index of regeneration. Formalin-fixed liver samples were embedded in paraffin, stained for immunohistochemistry with proliferating cell nuclear antigen (PCNA) antibody, and the labeling index was calculated. Immunohistochemistry was also performed with Shh and Gli-1 antibodies.

Results

The liver/body weight ratio gradually increased in both the 70 and 90 % Hx, groups. The hepatocytes were strongly stained for PCNA at 24 h after Hx. Non-parenchymal cells were gradually stained by PCNA from 24 to 72 h after Hx. Shh and Gli-1 expression in hepatocytes was higher after 24 h than at other times and then gradually decreased. Shh and Gli-1 expression in non-parenchymal cells increased gradually, and was found mainly in liver zone I at 72 h after 70 and 90 % Hx.

Conclusions

The expression of both markers suggested that Shh signaling contributes to tissue reconstruction after Hx.     

Induction of experimental proteinuria in vivo following infusion of human plasma hemopexin

BACKGROUND: The human plasma constituent hemopexin (Hx), following incubation with renal tissue, is able to induce glomerular alterations in vitro that are similar to those seen in minimal change disease (MCD). Whether this acute phase reactant is also able to induce proteinuria and minimal change-like alterations in vivo is questioned. METHODS: In the first set of experiments, Hx (4.0 mg in 5.0 mL saline) or equal amounts of control fraction, that is, heat-inactivated Hx (HI-Hx), were infused into conscious rats (N = 6) that had been surgically equipped with a cannula inserted into the suprarenal artery (SRA), enabling direct contact of the infusate and the renal microvasculature. Each animal received HI-Hx at day 1 for 15 minutes (flow rate 20.0 mL/h), subsequently followed by saline for seven hours (Flow rate 5.0 mL/h), after which the cannula was disconnected. At day 2, identical infusions in the same rat were carried out, using native Hx. Urine samples collected every 30 minutes during the experiments were monitored for protein content using standard methods. In the second set of experiments, unilateral perfusion was done ex vivo in anesthetized rats with Hx (N = 5) or HI-Hx (N = 3; 1.5 mg/mL; 4.0 mL during 6 min). After reconnection of the circulation, urine samples of both kidneys were collected every 30 minutes during five hours via ureter cannulation. Urinary protein (expressed as the difference in excretion between perfused and nonperfused kidney) was calculated in mg/24 h. In additional experiments, rats were sacrificed two hours after perfusion of Hx or heat-inactivated (control) Hx (first set of experiments) or after five hours (second set of experiments), and kidneys were processed for immunohistochemical and ultrastructural examination. RESULTS: The results of experiment 1 show a significant increase of proteinuria after Hx infusion versus HI-Hx (means +/- SD, 41.91 +/- 16.01 mg/24 h vs. control, 21.22 +/- 5.69 mg/24 h; P 相似文献   

Intestinal gram-negative bacterial overgrowth in vivo augments the in vitro response of Kupffer cells to endotoxin.

A number of disease states and therapeutic maneuvers common to surgical patients can result in changes in the intestinal flora, permitting bacterial overgrowth and translocation of bacteria to gut lymphoid tissue. It is possible that these changes in gut flora increase portal levels of several factors that are capable of altering macrophage activation state, including endotoxin, lymphokines, and eicosanoids. Since Kupffer cells are directly exposed to gut factors via the portal circulation, changes in intestinal flora may influence Kupffer cell responses. Using germfree rats, it has previously been shown that the presence of gut bacterial flora is important in inducing Kupffer cells to respond to endotoxin, and that an overgrowth of gram-negative bacteria can further augment Kupffer cell responses, supporting the above-mentioned hypothesis. The current set of experiments examines how intestinal gram-negative bacterial overgrowth in normal adult rats effects the response of Kupffer cells to septic stimuli. Kupffer cells were obtained from conventional rats with induced intestinal overgrowth with Escherichia coli C25 for 2 or 7 days. After 2 days of overgrowth, Kupffer cells were only slightly less responsive to lipopolysaccharide (LPS) than control Kupffer cells. However, after 7 days of overgrowth, when placed in coculture with normal hepatocytes, Kupffer cells were significantly more responsive to LPS (p less than 0.001), inducing a greater degree of suppression in hepatocyte protein synthesis at lower LPS concentrations. When cultured alone, Kupffer cells from these animals also produced more interleukin-1 (p less than 0.002) and prostaglandin E2 (PGE2) (p less than 0.009) in response to LPS. These results show that intestinal gram-negative bacterial overgrowth in conventional rats can have direct influences on the response of hepatic macrophages to septic stimuli, and provides further support to the hypothesis that imbalances in the intestinal flora can effect the responses of immune cells in other sites of the body.     

Glutathione protects the rat liver against reperfusion injury after prolonged warm ischemia

OBJECTIVE: To evaluate the potential of postischemic intravenous infusion of the endogenous antioxidant glutathione (GSH) to protect the liver from reperfusion injury following prolonged warm ischemia. BACKGROUND DATA: The release of reactive oxygen species (ROS) by activated Kupffer cells (KC) and leukocytes causes reperfusion injury of the liver after warm ischemia. Therefore, safe and cost-effective antioxidant strategies would appear a promising approach to prevent hepatic reperfusion injury during liver resection, but need to be developed. METHODS: Livers of male Lewis rats were subjected to 60, 90, or 120 minutes of normothermic ischemia. During a 120 minutes reperfusion period either GSH (50, 100 or 200 micromol/h/kg; n= 6-8) or saline (n= 8) was continuously administered via the jugular vein. RESULTS: Postischemic GSH treatment significantly prevented necrotic injury to hepatocytes as indicated by a 50-60% reduction of serum ALT and AST. After 1 hour of ischemia and 2 hours of reperfusion apoptotic hepatocytes were rare (0.50 +/- 0.10%; mean +/- SD) and not different in GSH-treated animals (0.65 +/- 0.20%). GSH (200 micromol GSH/h/kg) improved survival following 2 hours of ischemia (6 of 9 versus 3 of 9 rats; P < 0.05). Intravital fluorescence microscopy revealed a nearly complete restoration of sinusoidal blood flow. This was paralleled by a reduction of leukocyte adherence to sinusoids and postsinusoidal venules. Intravenous GSH administration resulted in a 10- to 40-fold increase of plasma GSH levels, whereas intracellular GSH contents were unaffected. Plasma concentrations of oxidized glutathione (GSSG) increased up to 5-fold in GSH-treated animals suggesting counteraction of the vascular oxidant stress produced by activated KC. CONCLUSIONS: Intravenous GSH administration during reperfusion of ischemic livers prevents reperfusion injury in rats. Because GSH is well tolerable also in man, this novel approach could be introduced to human liver surgery.     

Liver nonparenchymal cells are stimulated to provide interleukin 6 for induction of the hepatic acute-phase response in endotoxemia but not in remote localized inflammation.

It has been postulated that Kupffer cells provide signals that regulate hepatocyte responses in sepsis and inflammation. Although in vitro data support such a hypothesis, to our knowledge, no in vivo evidence has been reported. We injected rats with lipopolysaccharide intraperitoneally to simulate sepsis or turpentine intramuscularly to mimic localized inflammation. Both treatments are known to induce the hepatic acute-phase response. Liver nonparenchymal cells and hepatocytes were isolated and placed in culture. Hepatocyte fibrinogen synthesis was measured as an indication of interleukin 6 exposure, while nonparenchymal interleukin 6 production was measured directly. Both lipopolysaccharide and turpentine stimulated a sharp increase in hepatocyte fibrinogen synthesis (turpentine greater than lipopolysaccharide). However, only lipopolysaccharide injection was associated with increased nonparenchymal cell interleukin 6 synthesis. Increased circulating levels of interleukin 6 could be found only after lipopolysaccharide injection. In addition, tumor necrosis factor synthesis was enhanced by lipopolysaccharide but not turpentine. Our data show that nonparenchymal cells are stimulated to provide the interleukin 6 signal to hepatocytes in endotoxemia but not in remote localized inflammation, even though both treatments stimulate the hepatic acute-phase response. Our findings support paracrine functions for liver sinusoidal cells in certain septic states.     

Urinary trypsin inhibitor reduces C-X-C chemokine production in rat liver ischemia/reperfusion

BACKGROUND AND AIM: Protease inhibitors attenuate ischemia/reperfusion injury. However, the underlying mechanisms by which protease inhibitors prevent reperfusion injury remain obscure. Neutrophils play an important role in reperfusion injury. We studied the effects of urinary trypsin inhibitor (UTI) on production of the C-X-C chemokine, cytokine-induced neutrophil chemoattractant (CINC), by Kupffer cells during ischemia/reperfusion of the liver. METHODS: Liver ischemia was induced in rats by occlusion of the portal vein for 30 min. UTI (50,000 U/kg) was injected intravenously 5 min before vascular clamping. Serum CINC concentrations were measured by enzyme-linked immunosorbent assay. Levels of CINC mRNA in the liver were determined by Northern blot analysis. We also examined the inhibitory effects of UTI on in vitro CINC production by peritoneal macrophages in response to neutrophil elastase (NE). RESULTS: Serum CINC concentrations increased and peaked 6 h after reperfusion. However, pretreatment of animals with UTI blunted this increase in CINC and significantly reduced CINC mRNA levels in the liver after ischemia/reperfusion. UTI also decreased neutrophil accumulation in the liver 24 h after reperfusion. In vitro CINC production by Kupffer cells from rats pretreated with UTI 3 h after ischemia/reperfusion was significantly decreased compared to those from untreated animals. UTI reduced NE activity in vitro in a dose-dependent manner, and UTI significantly reduced in vitro CINC production by peritoneal macrophages stimulated with NE. CONCLUSION: UTI reduces the production of CINC by Kupffer cells stimulated with NE, attenuating ischemia/reperfusion injury of the liver.     

70%门静脉分支高位结扎大鼠肝组织细胞凋亡及相关基因Bax和Bcl-2 mRNA的表达

目的 观察70%门静脉分支高位结扎后大鼠肝组织细胞凋亡及相关基因Bax,Bcl-2的表达,以探讨肝细胞凋亡的发生机制.方法 Wistar大鼠60只,随机分成假手术对照组(n=30)和门静脉结扎组(n=30).观察术后第12小时和第1,2,3,7,14天的肝脏大体结构和血浆转氨酶的变化.用细胞凋亡原位末端标记技术(TUNEL)对结扎侧肝细胞凋亡进行定量分析,光学显微镜下观察未结扎侧肝细胞的增殖情况,采用逆转录-多聚酶链反应(RT-PCR)检测肝脏组织中Bax和Bcl-2 mRNA的表达.结果 70%门静脉分支高位结扎后,结扎侧肝叶以细胞凋亡的方式呈进行性萎缩变小,对侧则以有丝分裂的方式成比例地代偿性增生.全肝的总质量维持恒定,肝脏功能基本保持正常.结扎侧肝组织中以Bax mRNA的升高为主,而未结扎侧肝组织中以Bcl-2 mRNA的升高为主.结论 近70%门静脉分支高位结扎后,结扎侧肝脏由于Bax mRNA表达升高引起肝细胞大量凋亡,未结扎侧由于Bcl-2 mRNA表达升高引起肝细胞增殖,在维持全肝的质量和功能中具有重要意义.     

Endotoxin modulation of hepatocyte secretory and cellular protein synthesis is mediated by Kupffer cells

We hypothesize that alterations of hepatocyte function in sepsis are modulated by endotoxin (lipopolysaccharide)-triggered Kupffer cells. In the present experiments the effect of lipopolysaccharide on secreted and cellular proteins synthesized by hepatocytes cultured alone or cocultured with Kupffer cells was investigated using polyacrylamide gel electrophoresis. Lipopolysaccharide had no direct effect on the types or amounts of secreted proteins synthesized by hepatocytes alone. Kupffer cells coculturing resulted in increased synthesis of some hepatocyte proteins (68k and 23k) whose production was not altered by lipopolysaccharide. In contrast, addition of lipopolysaccharide to the hepatocyte-Kupffer cell coculture substantially decreased synthesis of several proteins (73k, 66k, and 35k). Despite an overall decrease in protein synthesis of hepatocytes cocultured with Kupffer cells after the addition of lipopolysaccharide, there was increased synthesis of several individual proteins (58k and 44k). Similar effects were seen in synthesis of cellular protein. The addition of recombinant interleukin 1 to hepatocytes alone or in coculture had no effect on the amount or type of protein synthesized. We conclude that Kupffer cells regulate the types and amounts of individual proteins synthesized by hepatocytes via mediators other than interleukin 1.