Toxicological Sciences 58, 208-215 (2000)
Copyright © 2000 by the Society of Toxicology
Systems Toxicology |
Lipopolysaccharide Augments Aflatoxin B1-Induced Liver Injury through Neutrophil-Dependent and -Independent Mechanisms
Department of Pharmacology and Toxicology, National Food Safety and Toxicology Center, and Institute for Environmental Toxicology, Michigan State University, East Lansing, Michigan 48824
Received May 2, 2000; accepted July 14, 2000
 |
ABSTRACT |
|---|
 TOP ABSTRACT INTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
|---|
Exposure to small, noninjurious doses of the inflammagen, bacterial endotoxin (lipopolysaccharide, LPS) augments the toxicity of certain hepatotoxicants including aflatoxin B1 (AFB1). Mediators of inflammation, in particular neutrophils (PMNs), are responsible for tissue injury in a variety of animal models. This study was conducted to examine the role of PMNs in the pathogenesis of hepatic injury after AFB1/LPS cotreatment. Male, Sprague-Dawley rats (250–350 g) were treated with either 1 mg AFB1/kg, ip or its vehicle (0.5% DMSO/saline), and 4 h later with either E. coli LPS (7.4 x 106 EU/kg, iv) or its saline vehicle. Over a course of 6 to 96 h after AFB1 administration, rats were killed and livers were stained immunohistochemically for PMNs. LPS resulted in an increase in PMN accumulation in the liver that preceded the onset of liver injury. To assess if PMNs contributed to the pathogenesis, an anti-PMN antibody was administered to reduce PMN numbers in blood and liver, and injury was evaluated. Hepatic parenchymal cell injury was evaluated as increased alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities in serum and from histologic examination of liver sections. Biliary tract alterations were evaluated as increased concentration of serum bile acids and activities of
-glutamyltransferase (GGT), alkaline phosphatase (ALP), and 5`-nucleotidase (5`-ND) in serum. Neutrophil depletion protected against hepatic parenchymal cell injury caused by AFB1/LPS cotreatment but not against markers of biliary tract injury. This suggests that LPS augments AFB1 hepatotoxicity through two mechanisms: one of which is PMN-dependent, and another that is not. Key Words: lipopolysaccharide; LPS; endotoxin; aflatoxin B1; sepsis; liver injury; sensitivity to intoxication; inflammation; neutrophil; PMN; hepatotoxicity.
|
INTRODUCTION |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
|---|
Aflatoxin B1 (AFB1) is a metabolite produced by the fungi, Aspergillus flavus and Aspergillus parasiticus, which are contaminants of grain foods. Treatment of animals with AFB1 causes hepatic injury in the periportal regions of liver lobules. This damage is evident acutely as hemorrhage, parenchymal cell necrosis, and injury to intrahepatic bile ducts.
Lipopolysaccharide (LPS, endotoxin) is a constituent of the outer membrane of the cell walls of Gram-negative bacteria. It has been extensively studied as a major contributing factor to the pathogenesis of bacterial infection. Although the mechanisms contributing to tissue injury from LPS are many and may vary among tissues, a commonality appears to be the involvement of host-derived, soluble, and cellular mediators of inflammation (Molvig et al., 1988
). Interactions among several of these appear to be necessary for full manifestation of tissue injury during LPS exposure (Hewett and Roth, 1993). For example, at large doses LPS produces midzonal liver injury in rats, and this requires inflammatory mediators such as neutrophils (Hewett et al., 1992; Jaeschke et al., 1993), Kupffer cells (Arthur et al., 1985; Brown et al., 1997), tumor necrosis factor-alpha (TNF-
) (Hewett et al., 1993), platelets (Pearson et al., 1995) and thrombin (Hewett and Roth, 1995; Moulin et al., 1996; Pearson et al., 1996).
Exposure to smaller doses of LPS initiates a more modest and noninjurious inflammatory response. However, exposure to such small doses of LPS can render the liver more sensitive to injury from hepatotoxic chemicals (reviewed by Roth et al., 1997), including AFB1 (Barton et al., 2000b). A small dose of LPS given to rats converted an otherwise nontoxic dose of AFB1 into one that is markedly hepatotoxic. In this model, both the periportal hepatocellular and bile-duct epithelial cell (BDEC) injuries induced by AFB1 were markedly enhanced by administration of LPS (Barton et al., 2000b). The mechanism behind this increased sensitivity has yet to be determined, but it seems likely that aspects of the inflammatory response initiated by exposure to small amounts of LPS may be responsible (Roth et al., 1997).
Neutrophils (polymorphonuclear leukocytes, PMNs) contribute to tissue damage in a number of disease models, including reperfusion injury following ischemia in the heart (Romson et al., 1983) or liver (Bautista et al., 1993; Langdale et al., 1993), and immune complex-mediated injury to lung (Johnson and Ward, 1981) or kidney (Johnson and Ward, 1982). Moreover, liver injury from large doses of bacteria (Arthur et al., 1986), alpha-naphthylisothiocyanate (ANIT) (Dahm et al., 1991) or LPS (Hewett et al., 1992) is prevented by prior depletion of PMNs, suggesting a causal role for PMNs in the pathogenesis. In a cell coculture system, activated rat PMNs injure hepatic parenchymal cells (Ganey et al., 1994; Mavier et al., 1988). Thus, evidence exists that PMNs can play a causal role in hepatic injury.
The involvement of PMNs in other liver injury models and the capacity of LPS to cause tissue PMN accumulation led us to hypothesize that the LPS-induced enhancement of AFB1 hepatotoxicity is dependent on PMNs. We tested this hypothesis by determining whether PMNs accumulate in liver before the onset of liver injury and whether prior depletion of PMNs prevents the augmentation of AFB1 hepatotoxicity by LPS.
|
MATERIALS AND METHODS |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
|---|
Animals and Materials
Male Sprague-Dawley rats (CD-Crl: CD-(SD)BR VAF/Plus; Charles River, Portage, MI) weighing 250–350 g were used in these studies. The reagent kits used for measuring serum markers of liver injury (ALT, 59-UV; AST, 58-UV; GGT, 419; bile acids, 450; ALP, 245; and 5`-ND, 265-UV) were purchased from Sigma Chemical Co. (St. Louis, MO). LPS derived from E. coli serotype 0128:B12 with an activity of 1.7 x 106 EU/mg was purchased from Sigma Chemical Co. A colorimetric, kinetic Limulus Amebocyte Lysate (LAL) assay was employed to estimate LPS concentration, using a kit (#50–650U) purchased from BioWhittaker (Walkersville, MD). Unless stated otherwise, all chemicals were purchased from Sigma.
Treatment Protocol
Rats, fasted for 24 h, were given 1 mg AFB1/kg or vehicle (0.5% DMSO in 0.9% sterile saline), ip, followed 4 h later by 7.4 x 106 EU LPS/kg or sterile saline via the tail vein. Doses of AFB1 and LPS used in this investigation caused minimal to no injury by themselves; however, as we have previously reported (Barton et al., 2000b), given together via this treatment regimen they caused pronounced liver injury. At 24 h after AFB1 administration, the rats were anesthetized with sodium pentobarbital (50 mg/kg, ip), and blood was drawn from the dorsal aorta, allowed to clot, and centrifuged to separate serum. Before the liver samples were placed in neutral buffered formalin, a mid-lobe radial section of the right anterior lobe was removed and frozen in liquid nitrogen. The 24 h time-point was chosen because the injury is maximal at this time (Barton et al., 2000b).
Determination of Hepatotoxicity
Serum markers of liver injury.
Reagent kits (see Animals and Materials) were used to measure serum markers of liver injury. Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities were measured spectrophotometrically by the methods of Wroblewski and LaDue (1956) and Karmen (1955), respectively. Serum gamma-glutamyltransferase (GGT), 5`-nucleotidase (5`-ND), and alkaline phosphatase (ALP) activities were measured by the methods of Szasz and Persijn (1974), Arkesteijn (1976), and Bowers and McComb (1966), respectively. Serum bile acids concentration was measured by the method of Mashige and colleagues (Mashige et al., 1981).
Histopathologic evaluation.
A mid-lobe, radial section of the right anterior lobe of the liver from each rat was fixed in 10% neutral buffered formalin and embedded in paraffin. Sections were cut at 5-micron thickness and stained with hematoxylin and eosin (H&E). Slides were coded, randomized, and evaluated with light microscopy.
TdT-mediated dUTP nick end labeling.
Apoptotic cells were detected with the procedure of Sgonc and co-workers (Sgonc et al., 1994) and from morphologic evaluation of H&E stained tissue. The in situ cell death detection reagent kit (POD) was purchased from Boehringer Mannheim (Indianapolis, IN; Cat. No. 1–684–817). In this method, formalin-fixed, paraffin-embedded liver sections were used for in situ TdT-mediated dUTP nick-end labeling (TUNEL) of 3`-hydroxy-DNA strand breaks. Briefly, 3`-hydroxy-DNA strand breaks were labeled with fluorescein-tagged nucleotides via terminal deoxynucleotidyl transferase and subsequently exposed to horseradish peroxidase-conjugated antifluorescein antibody. Staining was developed with diaminobenzidine (DAB), and sections were counterstained with methyl green. Between 2000 and 2500 hepatocytes per slide were counted in 12–20 randomly selected fields at 400x using a light microscope (Olympus BX50; Lake Success, N.Y.), and the percentage (labeling index) of cells that were stained and had apoptotic morphology was determined. Apoptotic morphology was defined by the morphological characteristics detailed by Kerr and co-workers (Kerr et al., 1972), i.e., (1) marked condensation of chromatin and cytoplasm; (2) cytoplasmic fragments with or without condensed chromatin; and (3) intra- and extracellular chromatin fragments.
Proliferating Cell Nuclear Antigen (PCNA) Immunohistochemistry
PCNA immunohistochemistry was conducted as described by Greenwell and colleagues (Greenwell et al., 1991). Briefly, the liver sections mounted on slides were first blocked with casein and then reacted with monoclonal antibody to PCNA (Dako Corporation, Carpentaria, CA). The antibody was then linked with biotinylated goat anti-mouse IgG antibody (Boehringer Mannheim, Indianapolis, IN), then labeled with streptavidin-conjugated peroxidase (Jackson Immunoresearch, West Grove, PA). Color was developed by exposing the peroxidase-labeled streptavidin to DAB, which forms a brown reaction product. The sections were then counterstained with Gill's hematoxylin. Each slide contained a section of duodenum as a positive control. G0 cells were blue and did not take the PCNA stain, whereas cells in the active stages of the cell cycle stained brown. Three cell types (1) parenchymal, (2) bile duct epithelial (BDEC), and (3) sinusoidal were examined per liver section for hyperplasia, and were assigned a score of 1–5. For parenchymal and sinusoidal cells, the following scores were given, based upon the percentage of cells stained: 1 = less than 5%; 2 = 5 to 10%; 3 = 11 to 15%; 4 = 16 to 20%; 5 = >20%. For BDECs, the following scores were given based upon the percentage of bile ducts which contained stained cells: 1 = less than 5% of the bile ducts; 2 = 5 to 25%; 3 = 26 to 50%; 4 = 51 to 75%; and 5 = >75%.
Neutrophil Depletion Protocol
Rabbit anti-rat neutrophil immunoglobulin (Ig) serum fraction was prepared by the method of Hewett and colleagues (Hewett et al., 1992) as modified by Bailie and colleagues (Bailie et al., 1994). Rats received anti-neutrophil Ig (NAb) or control Ig (CAb) (0.5 ml via the tail vein) at 16 and 8 h before AFB1 treatment. Four h after AFB1 administration, LPS was administered. Twenty-four h after AFB1 administration, the rats were anesthetized and killed, and injury was assessed. Blood PMN concentration was determined from total blood leukocyte numbers, assessed using an automated cell counter (Serono-Baker Diagnostics, Model System 9000, Allentown, PA) and differential counting of cells in modified Wrights-stained blood smears. Depletion of hepatic PMNs was assessed by enumeration of PMNs in liver sections.
Enumeration of Hepatic PMN
PMNs in liver sections were visualized using an immunohistochemical technique (Pearson et al., 1995). Liver sections were fixed, embedded in paraffin, and sectioned at 6 microns. Paraffin was removed from the tissue sections with xylene before staining. PMNs within the liver tissue were stained using a rabbit anti-PMN Ig. This anti-PMN Ig was isolated from serum of rabbits immunized with rat PMNs, as described previously (Hewett et al., 1992). After incubation with the primary antibody, the tissue sections were incubated with biotinylated goat anti-rabbit IgG, avidin-conjugated alkaline phosphatase, and Vector Red substrate to stain the PMNs within the tissue. PMNs in each section were enumerated in 20 evenly distributed, randomly selected, high-power (400x) fields (HPFs).
Statistical Analysis
Results are expressed as mean ± SE of groups of 5–25 rats. Homogeneity of variance was tested using the F-max test. If the variances were homogenous, data were analyzed using a completely randomized, factorial ANOVA. Individual comparisons were made with Tukey's test. For data sets with nonhomogenous variances, Kruskal-Wallis`s nonparametric ANOVA was used; individual comparisons were made with Dunn's multiple comparisons test. The criterion for significance was p < 0.05 for all comparisons.
|
RESULTS |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
|---|
Hepatic PMN Accumulation after AFB1/LPS Cotreatment
We reported previously that, in rats treated with AFB1/LPS, serum markers of hepatocellular injury and cholestasis were unaffected 6 h after AFB1 but were markedly elevated by 24 h (Barton et al., 2000b
). To characterize the development of hepatic PMN accumulation, liver tissue was assessed immunohistochemically at various times after the injection of AFB1 and/or LPS (Fig. 1). An increase in hepatic PMNs was not observed after administration of AFB1 alone. In contrast, LPS treatment resulted in a significant increase within 6 h that peaked by 24 h, and returned to normal by 72 h. The distribution of these cells was panlobular; however, midzonal accumulation was more pronounced. This increase was unaffected by cotreatment with AFB1.
|
Effect of NAb on PMN Numbers
AFB1/LPS cotreated rats that received control antibody from non-immunized rabbits (CAb) had a large increase in blood PMNs 24 h after AFB1 administration as compared to Veh/Veh-treated rats that received CAb (Fig. 2A
). Administration of PMN antibody from immunized rabbits (NAb) markedly attenuated this increase. There was also a pronounced accumulation of PMNs in liver tissue from AFB1/LPS cotreated rats that received Cab (Fig. 2B). This increase was greatly diminished in the rats that received NAb.
|
Effect of PMN Depletion on AFB1/LPS-Induced Hepatic Parenchymal Cell Injury
Hepatic parenchymal cell injury was estimated by measuring serum ALT and AST activities 24 h after the injection of AFB1. AFB1/LPS cotreated rats receiving CAb had a large increase in serum ALT (Fig. 3A
). Administration of NAb prevented this increase. Similar results were observed for serum AST activity (Fig. 3B).
|
These findings were supported by histological examination of liver sections for necrotic or swollen parenchymal cells. Necrotic cells were identified by pyknotic nuclei, indistinct cell borders, and vacuolization. Swollen cells were identified by cell enlargement and eosinophilic staining of the cytoplasm. The lesions found in AFB1/LPS-treated rats have been described in detail elsewhere (Barton et al., 2000b
). Livers of AFB1/LPS cotreated rats given CAb had widespread areas of single-cell or foci of oncotic necrosis characterized by hypereosinophilic cytoplasm and darkly stained nuclear fragments. These were frequent in the periportal areas, but they occurred to a lesser extent in midzonal regions and were absent in centrilobular regions. By contrast, livers from AFB1/LPS-cotreated rats given NAb had occasional single-cell necrosis only in periportal areas.
Effect of PMN Depletion on AFB1/LPS-Induced Biliary Injury
Cholangiodestructive cholestasis was estimated through examination of biochemical markers in serum and by histology. Increased 5`-ND, ALP, and GGT activities and bile acid concentration in the serum were observed in AFB1/LPS cotreated rats that were given CAb (Fig. 4). Administration of NAb did not diminish these increases.
|
Effect of PMN Depletion on AFB1/LPS-Induced Apoptosis
Previously, we reported that LPS treatment resulted in a small yet significant increase in apoptosis associated with single, hepatic parenchymal cells scattered throughout the lobule (Barton et al., 2000b
). Furthermore, this increase was unaffected by cotreatment with AFB1. To examine if neutrophil depletion altered apoptosis, TUNEL assay was conducted. Neutrophil depletion did not alter TUNEL staining (Fig. 5). These findings were further corroborated through the observation of cytoplasmic cell fragments and cells with condensed nuclear chromatin or chromatin fragmentation indicative of apoptosis in H&E sections.
|
Effect of PMN Depletion on AFB1/LPS-Induced Hepatocellular Hyperplasia
Previously, we reported (Barton et al., 2000b
) that LPS given alone stimulated hyperplasia of both sinusoidal and parenchymal cells, and AFB1 given alone stimulated hyperplasia of BDECs. Furthermore, this latter effect was enhanced with the co-administration of the 2 compounds. To examine if neutrophil depletion altered cellular hyperplasia, PCNA immunohistochemistry was conducted. This assay was chosen because it allows identification of all cells that are in any of the active stages of the cell cycle (i.e., not in G0). Neutrophil depletion attenuated sinusoidal and parenchymal cell PCNA staining; however, staining of BDECs remained unaltered (Table 1).
|
|
DISCUSSION |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
|---|
We reported recently that in rats treated with AFB1/LPS, serum markers of hepatocellular injury and cholestasis were unaffected 6 h after AFB1 treatment but were markedly elevated by 24 h (Barton et al., 2000b
). PMNs were more noticeable in H&E-stained liver sections from the groups that received LPS. To verify that there was an increase in PMNs, these cells were stained immunohistochemically and quantified 6 to 96 h after AFB1 administration. LPS administration resulted in a significant increase in PMNs in the liver within 2 h after its administration, irrespective of AFB1 co-administration. The numbers continued to increase until 24 h. By 48 h, the numbers of PMNs had declined, and by 72 h there was no longer an elevation. Previously, we reported that we did not observe injury to parenchymal cells until 24 h in this model (Barton et al., 2000b). Therefore, the accumulation of PMNs in the liver preceded the onset of liver injury. This suggested that the PMNs did not arrive in response to dead cells and cellular debris. To evaluate if the PMNs contributed to the pathogenesis in this model, an anti-neutrophil antibody (NAb) was administered to decrease the PMN numbers prior to AFB1/LPS treatment. The NAb treatment regimen decreased blood PMN concentration by approximately 85% and markedly reduced the hepatic PMN accumulation that followed AFB1/LPS treatment. This reduction in PMNs was associated with prevention of oncotic necrosis to hepatic parenchymal cells.
LPS at this dosage produced a modest increase in apoptosis, irrespective of AFB1 treatment (Barton et al., 2000b). Interestingly, although PMN-depletion prevented oncotic necrosis of parenchymal cells in this model, it did not alter the apoptotic response. This suggests that oncotic necrosis is PMN-dependent, whereas apoptosis results from a different mediator.
Increases in circulating endotoxin trigger a systemic inflammatory response in a variety of clinical conditions (Bone, 1992; Deitch, 1992; Kelly et al., 1997). In animal models, PMNs have been implicated as contributors to tissue damage. These cells also contribute to chemically induced liver injury in several models, including retinol potentiation of carbon tetrachloride hepatotoxicity (Badger et al., 1996), large dose of endotoxin (Hewett et al., 1992), and ANIT hepatotoxicity (Dahm et al., 1991). It is clear, however, that the mere presence of PMNs is not sufficient to cause damage, since hepatic PMN accumulation was similar in rats treated with LPS or the AFB1/LPS combination, yet only the latter treatment caused liver injury (Barton et al., 2000b).
PMNs release not only reactive oxygen species but also serine proteases such as cathepsin G and elastase, which can injure hepatic parenchymal cells of liver (Hill and Roth, 1998; Ho et al., 1996). PMN-derived proteases are important mediators of hepatocellular injury in rats cotreated with LPS and galactosamine (Okabe et al., 1993). The mechanism(s) by which PMN-derived proteases cause hepatocellular damage has not been completely characterized, but it is known that they can induce death of other cells by rupturing the plasma membrane (Varani et al., 1989). It is possible that PMN-induced hepatocellular injury in the AFB1/LPS model is mediated by this action; however, other mechanisms cannot presently be ruled out.
PMN-depletion did not afford protection against injury to BDECs and markers of cholestasis after AFB1/LPS treatment. This suggests that LPS augments AFB1-induced cholestatic injury through a mechanism independent of PMNs.
In contrast to observations here with AFB1/LPS, biliary injury in response to ANIT is PMN-dependent (Dahm et al., 1991). A hallmark of hepatotoxicity from ANIT is an early and marked accumulation of PMNs (Goldfarb et al., 1962) next to periportal hepatocytes as well as adjacent to BDECs within portal triads (Dahm et al., 1991). This accumulation precedes cellular injury (Goldfarb et al., 1962; McLean and Rees, 1958). Like AFB1, ANIT administration to rats results in periportal lesions characterized by injury to parenchymal cells as well as BDECs. Prior neutrophil depletion protects against injury to both cell types, suggesting a causal role for PMNs in ANIT pathogenesis (Dahm et al., 1991). Why injury to BDECs is PMN-dependent in the ANIT model but not in the AFB1/LPS model remains unclear.
It is reasonable to hypothesize that an LPS-induced inflammatory mediator other than PMNs may be responsible for the increased susceptibility of BDECs to AFB1 toxicity. One candidate is tumor necrosis factor-alpha (TNF), which is a critical mediator of injury in other models. In a preliminary study, we found that elimination of the LPS-induced increase in serum TNF concentration by neutralizing antibody or pentoxifylline treatment attenuated injury to both BDECs and parenchymal cells after AFB1/LPS cotreatment (Barton et al., 2000a). TNF has numerous actions that may render it a critical mediator in this model, including effects on inflammatory cells and on xenobiotic metabolism. Although it is possible that TNF might affect toxicity by altering the metabolism of AFB1, it is unlikely that this cytokine increases AFB1 bioactivation, since it decreases the synthesis of responsible P-450 isoforms (Warren et al., 1999; Pous et al., 1990; Bertini et al., 1988). In another model of inflammatory liver injury (Hewett et al., 1993), evidence suggested that interaction occurs between TNF and PMNs; whether or not interaction among these factors is important in augmentation of AFB1 hepatotoxicity by LPS remains to be determined.
Cell division and tissue repair occur in response to tissue injury (Mehendale, 1991). Parenchymal cell hyperplasia was attenuated after PMN-depletion in rats given AFB1/LPS. However, PMN-depletion was not associated with attenuation of BDEC hyperplasia. Since injury to BDECs is independent of PMNs, these results suggest that the hyperplasia occurred in response to injury.
In summary, the results of this study demonstrate that LPS-induced inflammation makes rats more susceptible to AFB1-induced injury to hepatic parenchymal cells by a mechanism that involves PMNs. However, potentiation of AFB1-induced injury to BDECs appears to be independent of these inflammatory cells. The mechanism by which BDECs are injured in this model requires further study.
|
ACKNOWLEDGMENTS |
|---|
The authors are grateful for support from NIH grant ES04139 and to Eva Barton, Kate Shores, and Anya King for technical assistance. C. C. Barton was supported by NIH training grant T32 ES07255.
|
NOTES |
|---|
1 To whom correspondence should be addressed. Fax: (517) 353-8915. E-mail: rothr{at}msu.edu.
|
REFERENCES |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
|---|
Arkesteijn, C. L. (1976). A kinetic method for serum 5`-nucleotidase using stabilised glutamate dehydrogenase. J. Clin. Chem. Clin. Biochem. 14, 155–158.[Web of Science][Medline]
Arthur, M. J., Bentley, I. S., Tanner, A. R., Saunders, P. K., Millward-Sadler, G. H., and Wright, R. (1985). Oxygen-derived free radicals promote hepatic injury in the rat. Gastroenterology 89, 1114–1122.[Web of Science][Medline]
Arthur, M. J., Kowalski-Saunders, P., and Wright, R. (1986). Corynebacterium parvum-elicited hepatic macrophages demonstrate enhanced respiratory burst activity compared with resident Kupffer cells in the rat. Gastroenterology 91, 174–181.[Web of Science][Medline]
Badger, D. A., Sauer, J. M., Hoglen, N. C., Jolley, C. S., and Sipes, I. G. (1996). The role of inflammatory cells and cytochrome P450 in the potentiation of CCl4-induced liver injury by a single dose of retinol. Toxicol. Appl. Pharmacol. 141, 507–519.[Web of Science][Medline]
Bailie, M. B., Hewett, J. A., Schultze, A. E., and Roth, R. A. (1994). Methylene dianiline hepatotoxicity is not leukocyte-dependent. Toxicol. Appl. Pharmacol. 124, 25–30.[Web of Science][Medline]
Barton, C. C., Barton, E. X., Ganey, P. E., and Roth, R. A. (2000a). Endotoxin potentiates aflatoxin B1-induced hepatotoxicity through a TNF-dependent mechanism. Toxicol. Sci. 54, 140.
Barton, C. C., Hill, D. A., Yee, S. B., Barton, E. X., Ganey, P. E., and Roth, R. A. (2000b). Bacterial lipopolysaccharide exposure augments aflatoxin B1-induced liver injury. Toxicol. Sci. 55, 444–452.
Bautista, A. P., Deaciuc, I. V., Jaeschke, H., Spolarics, Z., and Spitzer, J. J. (1993). Pathophysiology of Shock, Sepsis, and Organ Failure (G. Schlag, and H. Redl, Eds.), pp. 915–934. Springer-Verlag, Berlin.
Bertini, R., Bianchi, M., Villa, P., and Ghezzi, P. (1988). Depression of liver drug metabolism and increase in plasma fibrinogen by interleukin 1 and tumor necrosis factor: A comparison with lymphotoxin and interferon. Int. J. Immunopharmacol. 10, 525–530.[Web of Science][Medline]
Bone, R. C. (1992). Toward an epidemiology and natural history of SIRS (systemic inflammatory response syndrome). JAMA 268, 3452–3455.
Bowers, G. N., and McComb, R. B. (1966). A continuous spectrophotometric method for measuring the activity of serum alkaline phosphatase. Clin. Chem. 12, 70–89.[Abstract]
Brown, A. P., Harkema, J. R., Schultze, A. E., Roth, R. A., and Ganey, P. E. (1997). Gadolinium chloride pretreatment protects against hepatic injury but predisposes the lungs to alveolitis after lipopolysaccharide administration. Shock 7, 186–192.[Web of Science][Medline]
Dahm, L. J., Schultze, A. E., and Roth, R. A. (1991). An antibody to neutrophils attenuates alpha-naphthylisothiocyanate-induced liver injury. J. Pharmacol. Exp. Ther. 256, 412–420.
Deitch, E. A. (1992). Multiple organ failure: Pathophysiology and potential future therapy. Ann. Surg. 216, 117–134.[Web of Science][Medline]
Ganey, P. E., Bailie, M. B., VanCise, S., Colligan, M. E., Madhukar, B. V., Robinson, J. P., and Roth, R. A. (1994). Activated neutrophils from rat injured isolated hepatocytes. Lab. Invest. 70, 53–60.[Web of Science][Medline]
Goldfarb, S., Singer, E. J., and Popper, H. (1962). Experimental cholangitis due to alpha-naphthylisothiocyanate (ANIT). Am. J. Pathol. 40, 685–697.
Greenwell, A., Foley, J. F., and Maronpot, R. R. (1991). An enhancement method for immunohistochemical staining of proliferating cell nuclear antigen in archival rodent tissues. Cancer Lett. 59, 251–256.[Web of Science][Medline]
Hewett, J. A., Jean, P. A., Kunkel, S. L., and Roth, R. A. (1993). Relationship between tumor necrosis factor- and neutrophils in endotoxin-induced liver injury. Am. J. Physiol. 265, G1011–G1015.
Hewett, J. A., and Roth, R. A. (1993). Hepatic and extrahepatic pathobiology of bacterial lipopolysaccharides. Pharmacol. Rev. 45, 381–411.[Web of Science]
Hewett, J. A., and Roth, R. A. (1995). The coagulation system, but not circulating fibrinogen, contributes to liver injury in rats exposed to lipopolysaccharide from Gram-negative bacteria. J. Pharmacol. Exp. Ther. 272, 53–62.
Hewett, J. A., Schultze, A. E., VanCise, S., and Roth, R. A. (1992). Neutrophil depletion protects against liver injury from bacterial endotoxin. Lab. Invest. 66, 347–361.[Web of Science][Medline]
Hill, D. A., and Roth, R. A. (1998). -Naphthylisothiocyanate causes neutrophils to release factors that are cytotoxic to hepatocytes. Toxicol. Appl. Pharmacol. 148, 169–175.[Web of Science][Medline]
Ho, J. S., Buchweitz, J. P., Roth, R. A., and Ganey, P. E. (1996). Identification of factors from rat neutrophils responsible for cytotoxicity to isolated hepatocytes. J. Leukoc. Biol. 59, 716–724.[Abstract]
Jaeschke, H., Farhood, A., Bautista, A. P., Spolarics, Z., and Spitzer, J. J. (1993). Complement activates Kupffer cells and neutrophils during reperfusion after hepatic ischemia. Am. J. Physiol. 264, G801–G809
Johnson, K. J., and Ward, P. A. (1981). Role of oxygen metabolites in immune complex injury of lung. J. Immunol. 126, 2365–2369.[Web of Science][Medline]
Johnson, K. J., and Ward, P. A. (1982). Biology of disease: Newer concepts in the pathogenesis of immune complex-induced tissue injury. Lab. Invest. 47, 218–226.[Web of Science][Medline]
Karmen, A. (1955). A note on the spectrophotometric assay of glutamic-oxalacetic transaminase in human blood. J. Clin. Invest. 34, 131.
Kelly, J. L., O'Sullivan, C., O'Riordain, M., O'Riordain, D., Lyons, A., Doherty, J., Mannick, J. A., and Rodrick, M. L. (1997). Is circulating endotoxin the trigger for the systemic inflammatory response syndrome seen after injury? Ann. Surg. 225, 530–541.[Web of Science][Medline]
Kerr, J. F., Wyllie, A. H., and Currie, A. R. (1972). Apoptosis: A basic biological phenomenon with wide-ranging implications in tissue kinetics. Br. J. Cancer 26, 239–257.[Web of Science][Medline]
Langdale, L. A., Flaherty, L. C., Liggitt, H. D., Harlan, J. M., Rice, C. L., and Winn, R. K. (1993). Neutrophils contribute to hepatic ischemia-reperfusion injury by a CD18-independent mechanism. J. Leukoc. Biol. 53, 511–517.[Abstract]
Mashige, F., Tanaka, N., Maki, A., Kamei, S., and Yamanaka, M. (1981). Direct spectrophotometry of total bile acids in serum. Clin. Chem. 27, 1352–1356.
Mavier, P., Preaux, A. M., Guigui, B., Lescs, M. C., Zafrani, E. S., and Dhumeaux, D. (1988). In vitro toxicity of polymorphonuclear neutrophils to rat hepatocytes: Evidence for a proteinase-mediated mechanism. Hepatology 8, 254–258.[Web of Science][Medline]
McLean, M. R., and Rees, K. R. (1958). Hyperplasia of bile ducts induced by alpha-naphthylisothiocyanate: Experimental biliary cirrhosis free from biliary obstruction. J. Pathol. Bacteriol. 76, 175–188.[Web of Science][Medline]
Mehendale, H. M. (1991). Role of hepatocellular regeneration and hepatolobular healing in the final outcome of liver injury. Biochem. Pharmacol. 42, 1155–1162.[Web of Science][Medline]
Molvig, J., Baek, L., Christensen, P., Manogue, K. R., Vlassara, H., Platz, P., Nielsen, L. S., Svejgaard, A., and Nerup, J. (1988). Endotoxin-stimulated human monocyte secretion of interleukin 1, tumour necrosis factor alpha, and prostaglandin E2 shows stable interindividual differences. Scand. J. Immunol. 27, 705–716.[Web of Science][Medline]
Moulin, F., Pearson, J. M., Schultze, A. E., Scott, M. A., Schwartz, K. A., Davis, J. M., Ganey, P. E., and Roth, R. A. (1996). Thrombin is a distal mediator of lipopolysaccharide-induced liver injury in the rat. J. Surg. Res. 65, 149–158.[Web of Science][Medline]
Okabe, H., Irita, K., Kurosawa, K., Tagawa, K., Koga, A., Yamakawa, M., Yoshitake, J., and Takahashi, S. (1993). Increase in the plasma concentration of reduced glutathione observed in rats with liver damage induced by lipopolysaccharide/D-galactosamine: Effects of ulinastatin, a urinary trypsin inhibitor. Circ. Shock 41, 268–272.[Web of Science][Medline]
Pearson, J. M., Schultze, A. E., Jean, P. A., and Roth, R. A. (1995). Platelet participation in liver injury from Gram-negative bacterial lipopolysaccharide in the rat. Shock 4, 178–186.[Web of Science][Medline]
Pearson, J. M., Schultze, A. E., Schwartz, K. A., Scott, M. A., Davis, J. M., and Roth, R. A. (1996). The thrombin inhibitor, hirudin, attenuates lipopolysaccharide-induced liver injury in the rat. J. Pharmacol. Exp. Ther. 278, 378–383.
Pous, C., Giroud, J. P., Damais, C., Raichvarg, D., and Chauvelot-Moachon, L. (1990). Effect of recombinant human interleukin-1 beta and tumor necrosis factor alpha on liver cytochrome P-450 and serum alpha-1-acid glycoprotein concentrations in the rat. Drug Metab. Dispos. 18, 467–470.[Abstract]
Romson, J. L., Hook, B. G., Kunkel, S. L., Abrams, G. D., Schork, M. A., and Lucchesi, B. R. (1983). Reduction in ultimate extent of ischemic myocardial injury by neutrophil depletion in the dog. Circulation 67, 1016–1023.
Roth, R. A., Harkema, J. R., Pestka, J. P., and Ganey, P. E. (1997). Is exposure to bacterial endotoxin a determinant of susceptibility to intoxication from xenobiotic agents? Toxicol. Appl. Pharmacol. 147, 300–311.[Web of Science][Medline]
Sgonc, R., Boeck, G., Dietrich, H., Gruber, J., Recheis, H., and Wick, G. (1994). Simultaneous determination of cell surface antigens and apoptosis. Trends Genet. 10, 41–42.[Web of Science][Medline]
Szasz, G. (1974). New substrates for measuring gamma-glutamyl transpeptidase activity. Z. Klin. Chem. Klin. Biochem. 12, 228.[Web of Science][Medline]
Varani, J., Ginsburg, I., Schuger, L., Gibbs, D. F., Bromberg, J., Johnson, K. J., Ryan, U. S., and Ward, P. A. (1989). Endothelial cell killing by neutrophils: Synergistic interaction of oxygen products and proteases. Am. J. Pathol. 135, 435–438.[Abstract]
Warren, G. W., Poloyac, S. M., Gary, D. S., Mattson, M. P., and Blouin, R. A. (1999). Hepatic cytochrome P-450 expression in tumor necrosis factor-alpha receptor (p55/p75) knockout mice after endotoxin administration. J. Pharmacol. Exp. Ther. 288, 945–950.
Wroblewski, F., and LaDue, J. S. (1956). Serum glutamic-pyruvic transaminase in cardiac hepatic disease. Proc. Soc. Exp. Biol. Med. 91, 569.
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  J. P. Luyendyk, P. J. Shaw, C. D. Green, J. F. Maddox, P. E. Ganey, and R. A. Roth Coagulation-Mediated Hypoxia and Neutrophil-Dependent Hepatic Injury in Rats Given Lipopolysaccharide and Ranitidine J. Pharmacol. Exp. Ther., September 1, 2005; 314(3): 1023 - 1031. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. P. Luyendyk, J. F. Maddox, G. N. Cosma, P. E. Ganey, G. L. Cockerell, and R. A. Roth Ranitidine Treatment during a Modest Inflammatory Response Precipitates Idiosyncrasy-Like Liver Injury in Rats J. Pharmacol. Exp. Ther., October 1, 2003; 307(1): 9 - 16. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. A. Roth, J. P. Luyendyk, J. F. Maddox, and P. E. Ganey Inflammation and Drug Idiosyncrasy--Is There a Connection? J. Pharmacol. Exp. Ther., October 1, 2003; 307(1): 1 - 8. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. B. Yee, U. M. Hanumegowda, J. A. Hotchkiss, P. E. Ganey, and R. A. Roth Role of Neutrophils in the Synergistic Liver Injury from Monocrotaline and Bacterial Lipopolysaccharide Exposure Toxicol. Sci., March 1, 2003; 72(1): 43 - 56. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. P. Luyendyk, B. L. Copple, C. C. Barton, P. E. Ganey, and R. A. Roth Augmentation of Aflatoxin B1 Hepatotoxicity by Endotoxin: Involvement of Endothelium and the Coagulation System Toxicol. Sci., March 1, 2003; 72(1): 171 - 181. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. P. Luyendyk, K. C. Shores, P. E. Ganey, and R. A. Roth Bacterial Lipopolysaccharide Exposure Alters Aflatoxin B1 Hepatotoxicity: Benchmark Dose Analysis for Markers of Liver Injury Toxicol. Sci., July 1, 2002; 68(1): 220 - 225. [Abstract] [Full Text] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||