Preventive effect of cyclosporin A on experimentally induced acute liver injury in rats

Abstract: We examined the effect of cyclosporin A (CsA) on the pathogenesis of acute experimental liver injury in rats induced by injection of heat-killed Propionibacterium acnes (P. acnes) and subsequent injection of lipopolysaccharide (LPS). Pretreatment with CsA significantly reduced serum alanine aminotransferase (ALT), serum tumor necrosis factor-α (TNF-α) production, without changing the TNF-α mRNA level in the liver, and plasma interferon-γ (IFN-γ), following LPS injection in this model. Twenty-four-hour mortality was also markedly improved, from 100% in the P. acnes plus LPS group to 0% in the CsA-pretreated group. Although direct addition of CsA to isolated hepatic macrophages from P. acnes-pretreated rats did not prevent the production of TNF-α and active oxygen species, isolated hepatic macrophages from P. acnes plus CsA-pretreated rats significantly reduced their production in response to the addition of LPS. These results suggest that CsA protects against P. acnes plus LPS-induced acute liver injury, not by direct inhibition of hepatic macrophage activation, but by indirect prevention of hepatic macrophage activation, presumably related to the reduction in plasma IFN-γ levels.     

An experimentally-induced acute hepatic failure model in various strains of mice

When BALB/cAJcl mice are intravenously injected with heat-killedPropionibacterium acnes (P. acnes) followed by an intravenous injection of lipopolysaccharide (LPS) 7 days later, massive necrosis is induced in the liver tissue and most of the mice die within 24 hours of LPS injection. Using this experimental model, acute hepatic failure was induced in various strains of mice and the difference in the response was studied. As a result, as in BALB/cAJcl mice, acut hepatic failure was also induced in BALB/ cAJcl-nu, AKR/J, C3H/HeNJcl, C57BL/6NJcl and DDy mice. However, as an exception, hepatic cell necrosis was hardly seen and the survival rate was remarkable high in C3H/HeJ mice, which genetically do not respond to LPS stimulation. These results indicate that for this experimental induction of acute hepatic failure, macrophages must be activated by the two-step stimulation ofP. acnes and LPS.     

Histochemical study of proliferating cells in the spleen in mice with acute hepatic injury

When heat-killed Propionibacterium acnes (P. acnes) and lipopolysaccharide (LPS) were injected into mice, liver cell necrosis with infiltrating neutrophils and macrophages were induced. Proliferating cells in the spleen were histochemically investigated. P. acnes injection rapidly produced hyperplasia of neutrophils and macrophages in the red pulp of the spleen. The proportion of Bromodeoxyuridine positive cells reached a peak at 5 days after injection of P. acnes. These results indicate that proliferating cells in the spleen after injection of P. acnes are mainly neutrophils and macrophages, which are the same kinds of infiltrating cells into the liver after injection of P. acnes and LPS.     

All-trans retinoic acid suppresses liver injury induced by Propionibacterium acnes and lipopolysaccharide in rats

All-trans retinoic acid (ATRA) has been reported to exert major effects on the immune system, including monocytes/macrophages. The present study was designed to determine whether ATRA would modulate macrophage-associated liver injury induced by Propionibacterium acnes and lipopolysaccharide (LPS) in rats. All-trans retinoic acid administration alleviated the liver injury and reduced the incidence of death following hepatic failure. Serum alanine aminotransferase (ALT) levels 5 h after, and survival rates within 12 h after the administration of LPS were significantly lower in the ATRA-treated group (134 ± 119 IU/L and 72.7%) compared with the control group (713 ± 411 IU/L and 18.2%; P < 0.05). Histological findings supported these results. These effects may be due to suppression of tumour necrosis factor-α (TNF-α) and superoxide anions produced by activated macrophages. Serum levels of TNF-α 1 h after LPS administration were significantly lower in the ATRA-treated group (60.5 ± 7.0 ng/mL) as compared with the control group (105.2 ± 39.3 ng/mL; P < 0.05). Formazan deposition that was generated by the perfusion of the liver with nitroblue tetrazolium, also suggested suppression of the release of superoxide anions from hepatic macrophages. These results suggest that ATRA acts as an immunomodulator in liver injury by suppressing the activation of liver macrophages.     

CTLA-4Ig suppresses liver injury by inhibiting acquired immune responses in a mouse model of fulminant hepatitis

Expression of costimulatory molecules is significantly upregulated in various organs in an animal model of severe hepatitis induced by injection of Propionibacterium acnes (P. acnes) and lipopolysaccharide (LPS). In the present study, we examined whether blockade of costimulatory signals by CTLA-4Ig can suppress the liver injury in this model. We injected an adenovirus encoding CTLA-4Ig (AdCTLA-4Ig) into mice 7 days before, on the same day, or 3 days after P. acnes priming. The virus was found to infect the liver preferentially, and CTLA-4Ig was detected in the serum as early as 2 days after viral injection. After injection of LPS, liver injury and survival rates were examined. Most of the mice not injected with AdCTLA-4Ig died within 12 hours after injection of LPS. In contrast, all the AdCTLA-4Ig-injected mice survived when the virus was injected 7 days before or on the same day as P. acnes priming. Importantly, hemorrhagic liver injury and serum alanine aminotransferase levels were significantly reduced after LPS injection even when AdCTLA-4Ig was injected 3 days after P. acnes priming. Immunological analyses showed that CTLA-4Ig inhibited the activation and expansion of P. acnes-specific CD4+ T cells in the hepatic lymph nodes, leading to a reduction in the recruitment of the cells to the liver. The total amounts of interferon-gamma, interleukin-12, and various chemokines in the liver were then decreased, resulting in inhibition of the secondary recruitment of not only T cells but also macrophages. In conclusion, CTLA-4Ig could be useful for treatment of severe liver injury.     

Experimental Liver Injury Induced by Propionibacterium acnes and Lipopolysaccharide in Macrophage Colony Stimulating Factor-Deficient Osteopetrotic (op/op) Mice

To clarify the involvement of growth anddifferention of liver macrophages mediated by macrophagecolony-stimulating factor (M-CSF) in the liver injuryinduced by Propionibacterium acnes (P. acnes) and lipopolysaccharide (LPS), we usedM-CSF-deficient osteopetrotic (op/op) mice. Seven daysafter injection of P. acnes, granulomas as well as thenumbers of Thy-1.2-, Mac-1-, and ERMP-20-positive cellsand F4/80-positive areas in the liver weresignificantly reduced in the op/op mice compared to thenormal littermates. After injection of LPS, serum levelsof alanine aminotransferase as well as concentrations of IL-1 and TNF- in the serum andliver were significantly lower in the op/op mice than inthe normal littermates, whereas the concentrations ofIL-1 and TNF- in the spleen were similar in op/op mice and normal littermates. Theseresults suggest that M-CSF plays a partial but highlysignificant role in the development of liver injuryinduced by P. acnes and LPS via an intrahepatic increase of primed macrophages including those ingranulomas, in response to P. acnes, which produceproinflammatory cytokines such as IL-1 andTNF-.     

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.     

Effects of bile acids on liver cell injury by cultured supernatant of activated liver adherents cells

When heat-killed Propionibacterium acnes (P. acnes) is intravenously injected into mice followed by an intravenous injection of a small amount of lipopolysaccharide (LPS) 7 days later, most of the mice die of massive hepatic cell necrosis within 24 hours of LPS injection. In addition, when the liver adherent cells including Kupffer cells are separated from the mice 7 days after P. acnes injection and incubated in vitro with LPS, remarkable activity of the cytotoxic factor is found in the culture supernatant. This cytotoxic factor is thought to cause liver injury. Using this experimental model, the effects of various bile acids on liver cell injury were studied. As a result, ursodeoxycholic acid and dehydrocholic acid suppressed liver cell injury induced by the cytotoxic factor. However, cholic acid, deoxycholic acid and chenodeoxycholic acid did not have any hepatocytoprotective effects.     

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.     

An experimentally-induced acute hepatic failure model in various strains of mice

When BALB/cAJc1 mice are intravenously injected with heat-killed Propionibacterium acnes (P. acnes) followed by an intravenous injection of lipopolysaccharide (LPS) 7 days later, massive necrosis is induced in the liver tissue and most of the mice die within 24 hours of LPS injection. Using this experimental model, acute hepatic failure was induced in various strains of mice and the difference in the response was studied. As a result, as in BALB/cAJc1 mice, acute hepatic failure was also induced in BALB/cAJc1-nu, AKR/J, C3H/HeNJc1, C57BL/6NJc1 and DDy mice. However, as an exception, hepatic cell necrosis was hardly seen and the survival rate was remarkable high in C3H/HeJ mice, which genetically do not respond to LPS stimulation. These results indicate that for this experimental induction of acute hepatic failure, macrophages must be activated by the two-step stimulation of P. acnes and LPS.     

Expression of tumor necrosis factor-α gene during allograft rejection following rat liver transplantation

Abstract: Background/Aims: Tumor necrosis factor-α (TNF-α) is believed to play a role in hepatic allograft rejection. However, the specific cellular population responsible for TNF-α production during hepatic allograft rejection is not known. Circulating monocyte-macrophage cells are the primary systemic sources of TNF-α. In the liver, Kupffer cells are the main producers of TNF-α. In this study, we determined which cells are involved in TNF-α production during allograft rejection after orthotopic liver transplantation. Methods: In situ hybridization was used to identify cells with TNF-α mRNA in the liver. Immunohistochemical staining with ED2 and ED3 was used to differentiate between cellular types (Kupffer cells versus infiltrating monocytes). To detect DNA fragmentation in liver cells, TdT-mediated biotin-dUTP nick-end labeling (TUNEL) was done. Studies were performed in the rat liver transplant model using rejecting (ACI to LEW) and non-rejecting (ACI to ACI) donor/recipient combinations. Results: In the control group, cells with TNF-α mRNA were rarely observed. In the rejection group, TNF-α mRNA was observed in mononuclear cells that were mainly within the vessels of the portal region and occasionally in the sinusoids. The cells with the signals for TNF-α mRNA were ED2-negative and ED3-positive. DNA fragementation was observed in hepatocytes as well as infiltrating mononuclear cells. Conclusions: The main producer of TNF-α may be infiltrating mononuclear cells such as monocyte-macrophage cells rather than Kupffer cells during allograft rejection after liver transplantation. Circulating monocyte-macrophages may play a role in the control of allograft rejection.     

The protective effect of cyclosporin A on experimentally-induced acute hepatic injury in mice

When heat-killed Propionibacterium acnes (P. acnes) and a small amount of endotoxin lipopolysaccharide (LPS) were intravenously injected into mice at a week's interval, most of them died of massive hepatic cell necrosis. This experimentally-induced acute liver injury was significantly inhibited by cyclosporin A (CsA), resulting in a remarkable improvement of the survival rate. This protective effect of CsA on acute liver injury was also histopathologically confirmed. To study the mechanism by which CsA protected the mice from fatal hepatic injury, adherent cells prepared from the murine liver 7 days after P. acnes injection were incubated with LPS in the presence of CsA, and the effect of CsA on the production of the cytotoxic factor from the adherent cells was estimated. As a result, CsA inhibited the activation of liver adherent cells and suppressed the release of the cytotoxic factor.     

Enhanced tumor necrosis factor and interleukin-1 in an experimental model of massive liver cell necrosis/fatal hepatitis in mice

Studies were conducted to investigate possible roles of tumor necrosis factor (TNF) and interleukin-1 (IL-1) in liver cell necrosis/fatal hepatitis in mice which were injected with Propionibacterium acnes (P.acnes) and subsequently 7 days later with a small dose of lipopolysaccharide-endotoxin (LPS). Higher serum levels of TNF were observed in the model, and enhanced production of both TNF and IL-1 was also found in hepatic as well as splenic adherent cells that were isolated from mice pretreated with P.acnes and were stimulated by LPS in vitro. When TNF substituted for LPS in the model, fatal hepatitis was also induced within 24 hrs, although the replacement of LPS by IL-1 resulted in no lethality. Moreover, when a combination of a near non-lethal doses of TNF and IL-1 substituted for LPS, 100% lethality was observed within 4 hrs. These results strongly suggest that both TNF and IL-1 are crucial soluble factors which are released by infiltrating macrophages in both liver and spleen, and are responsible for the development of liver cell necrosis/fatal hepatitis. In particular, TNF is one of the principal mediators of liver injury and IL-1 may potentiate the lethal effect of TNF in an LPS-related experimental model of massive liver cell necrosis.     

A Solitary Necrotizing Sarcoid Granulomatosis-like Pulmonary Lesion Possibly Associated with Propionibacterium acnes and Mycobacterium avium

We report a case of a pulmonary necrotizing sarcoid granulomatosis (NSG)-like lesion possibly associated with coinfection of Mycobacterium avium and Propionibacterium acnes. A solitary nodule in the right middle lobe of the lung was notable for coagulative necrosis with aggregates of sarcoid-like epithelioid granulomas. Small arteries were damaged by granulomas. Both M. avium and P. acnes were detected in the lesion. Furthermore, more P. acnes genomes were detected in the granulomas than in the non-lesion lung. These findings blur the pathophysiologic boundaries among NSG, sarcoidosis, and mycobacteriosis, and suggest that NSG needs to be recognized as continuous spectra of sarcoidosis/mycobcteriosis.     

Induction of CINC (interleukin-8) production in rat liver by non-parenchymal cells

The production of interleukin-8 (CINC: cytokine-induced neutrophil chemo-attractant) from different cell populations in the rat liver was studied and cells related to the initiation of CINC production in lipopolysaccharide (LPS)-injected endotoxaemic rats were characterized. Sinusoidal endothelial cells (16.4 ± 10.6 ng/mL) produced significantly higher amounts of CINC in 24 h primary cultures compared with hepatocytes (0.9 ± 0.9 ng/mL; P < 0.05) and Kupffer cells (6.5 ± 5.1 ng/mL; P < 0.05). Lipopolysaccharide, tumour necrosis factor-α (TNF-α), and interleukin-1α (IL-1α) stimulated different liver cell populations to produce CINC; LPS mainly stimulated Kupffer cells, TNF-α stimulated hepatocytes and IL-1α stimulated all three types of cells. Intraperitoneal injection of LPS (4 mg/kg) caused CINC accumulation in non-parenchymal cells of the rat liver within 1 h of injection, as shown by immunohistochemical staining. In contrast, CINC-positive hepatocytes were not seen until 3 h after injection of LPS. Ethanol was not a direct inducer of CINC production by rat hepatocytes in vitro. These findings strongly suggest that non-parenchymal liver cells, including sinusoidal endothelial cells, are the main source of CINC. Our data also suggest that during endotoxaemia, CINC production is initiated by non-parenchymal cells and this is followed by production from hepatocytes.     

The resistance of P. acnes--primed interferon gamma-deficient mice to low-dose lipopolysaccharide-induced acute liver injury

Endotoxin has been identified as a principal mediator of sepsis, often with resulting multiple organ failure. Although interferon gamma (IFN-gamma) has a central role in controlling bacterial infection through the activation of macrophages and T lymphocytes, it can also enhance the harmful effects of the inflammatory response. To examine the role of IFN-gamma in lipopolysaccharide (LPS)-induced injury, we administered LPS (20 or 800 microg/mouse) alone or as low-dose LPS (20 microg/mouse) 7 days after heat-killed Propionibacterium acnes (P. acnes) injection into wild-type C57BL/6 (B6) mice or IFN-gamma-deficient (GKO) mice (B6 background). Although low-dose (20 microg) LPS alone had no effect on survival, the administration of 800 microg LPS alone resulted in 100% mortality in both B6 and GKO mice without significant hepatic mononuclear cellular infiltration or differences in elevated plasma tumor necrosis factor alpha (TNF-alpha), interleukin 6 (IL-6), and IL-12 levels. In contrast, mortality after low-dose (20 microg) LPS challenge in P. acnes-primed B6 mice was 100%, but 0% in GKO mice. In vivo plasma cytokine (IFN-gamma, TNF-alpha, IL-6, and IL-12) levels and in vitro cytokine production by hepatic mononuclear cells were significantly higher in B6 mice compared with GKO mice. Associated hepatic mononuclear cellular infiltration, multifocal liver necrosis, hepatomegaly, and splenomegaly were found in B6 mice, but not in GKO mice. Finally, the anti-inflammatory NK1.1+CD4+ cell proportion of hepatic infiltrating mononuclear cell numbers 7 days after P. acnes administration was significantly reduced in B6 compared with GKO mice, whereas the proportion of inflammatory NK1.1+CD4- cells was increased. In conclusion, these data suggest that IFN-gamma mediates P. acnes-primed low-dose LPS injury through the hepatic infiltration of mononuclear cells and the subsequent elevation of inflammatory cytokines after LPS challenge, whereas the lethal effects of high-dose LPS alone does not depend on the presence of IFN-gamma.     

Interleukin-12 regulates natural killer cell-dependent Propionibacterium acnes-primed, lipopolysaccharide-induced liver injury.

Aim: Interleukin (IL)-12, produced primarily by macrophage/monocytes, modulates mature T and natural killer (NK) cell functions, including cytotoxicity and cytokine production. Methods: To determine the role of IL-12 in Propionibacterium acnes (P. acnes)-primed, lipopolysaccharide (LPS)-induced liver injury, mice were injected with an anti-IL-12 monoclonal antibody (mAb) 1 and 2 days before P. acnes injection (day 0) or 5 and 6 days before LPS challenge (day 7). The survival rates, plasma cytokine levels, and liver mononuclear cell phenotypes were evaluated for the mice treated with and without anti-IL-12 mAb. Results: The observed mortality with P. acnes-primed, LPS-induced liver injury in C57BL/6 (B6) mice was 100%, but was reduced to 0% in interferon (IFN)-gamma receptor-deficient mice and B6 mice treated with anti-IL-12 mAb on 1 and 2 days before P. acnes exposure (day 0). The plasma IFN-gamma levels weresignificantly lower (P < 0.05), and significantly less ( approximately 90% reduction) hepatic infiltrating mononuclear and NK1.1 cells were also found in the IL-12 mAb-treated, P. acnes-primed mice. The plasma cytokine levels after LPS challenge and in vitro cytokine release by liver mononuclear cells were significantly lower (P < 0.05) in the mice treated with anti-IL-12 mAb prior to P. acnes exposure. The in vivo administration of anti-NK1.1 mAb also improved survival in this liver injury model. Conclusion: IL-12-regulated IFN-gamma production is crucial during the priming phase by P. acnes, but not at the time of the subsequent LPS challenge. NK1.1(+)CD3(-)CD4(-) NK or NK1.1(+)CD3(+)CD4(-) NKT cells are important in this model of liver injury.     

Tumor necrosis factor alpha has a crucial role in increased reactive oxygen species production in platelets of mice injected with lipopolysaccharide

Increased reactive oxygen species (ROS) production leads to tissue damage observed in sepsis and lipopolysaccharide (LPS)-exposed animals. LPS stimulates cytokines releasing, including tumor necrosis factor alpha (TNF-α), that is important to ROS production. Platelets, considered inflammatory cells, generate ROS when exposed to LPS in vivo, but not when they are incubated in vitro with this compound. Therefore, we investigated the role of TNF-α on the increased intraplatelet ROS levels after LPS treatment. Mice were injected with LPS (1 mg/kg) or TNF-α (10 ng/kg), and blood was collected to prepare the washed platelets. Animals were treated with infliximab (anti-TNF-α antibody), R-7050 (non-selective TNF-α receptor antagonist) or apocynin (NADPH oxidase inhibitor). At 48 h after LPS or TNF-α injection, the ROS levels in ADP (25 µM)-activated platelets were evaluated by flow cytometry. Our data showed that injection of mice with LPS increased by 4-fold the ROS production (p < 0.05), which was significantly reduced by the treatments with infliximab, R-7050 or apocynin. Injection of mice with TNF-α markedly elevated the ROS formation in platelets (p < 0.05) that was reduced by infliximab, R-7050 or apocynin treatments. In separate experiments, platelets from saline-injected mice were incubated with TNF-α (30 to 3000 pg/mL) in absence or presence of infliximab, R-7050, apocynin or GKT137831 (NOX1/NOX4 inhibitor) before ROS measurements. TNF-α in vitro markedly increased the ROS levels, an effect significantly reduced by all treatments. Therefore, platelets are involved in the oxidative stress induced by LPS through TNF-α action, and NADPH oxidase takes part in this effect.     

Expression of hepatocyte growth factor and transforming growth factor β1 mRNA inP. acnes and lipopolysaccharide-treated rats

Hepatocyte growth factor (HGF), a potent hepatocyte mitogen in vitro, triggers hepatocyte regeneration after partial hepatectomy and acute liver cell necrosis induced by chemicals. In contrast, tranforming growth factor ₁ inhibits hepatocyte proliferation in vitro and suppresses liver regeneration in vivo. We assessed the expression of HGF and TGF ₁ mRNA in an endotoxin-related hepatic cell necrosis model. Intravenous injection of Gram-negative lipopolysaccharide (LPS) into rats previously given heat-killedPropionibacterium acnes induced endotoxinrelated hepatic cell necrosis. In this model, serum ALT began to rise to more than 100 IU as early as 3 h after LPS injection, reaching 300 IU 12 h after injection. HGF mRNA levels in the liver did not increase significantly until 5 h after LPS injection; at 12 h, they had increased about threefold compared with controls. TGF ₁ mRNA expression increased threefold afterP. acnes treatment alone and increased further after LPS injection. In the spleen, HGF mRNA levels increased within 3 h, but in the lung no increase in HGF mRNA was observed. Early elevation of liver TGF ₁ mRNA levels and delayed elevation of HGF mRNA levels, with low expression of HGF in the lung, may play a role in the pathogenesis of endotoxin-related hepatic necrosis.This study was supported by a Grant for Scientific Research (no. 04304038) from the Japanese Ministry of Education, Science, and Culture.