The coagulation system contributes to synergistic liver injury from exposure to monocrotaline and bacterial lipopolysaccharide

Diagnosis, toxicological mechanism, and detoxification for hepatotoxicity induced by pyrrolizidine alkaloids from herbal medicines or other plants

Pyrrolizidine alkaloids (PAs) are one type of phytotoxins distributed in various plants, including many medicinal herbs. Many organs might suffer injuries from the intake of PAs, and the liver is the most susceptible one. The diagnosis, toxicological mechanism, and detoxification of PAs-induced hepatotoxicity have been studied for several decades, which is of great significance for its prevention, diagnosis, and therapy. When the liver was exposed to PAs, liver sinusoidal endothelial cells (LSECs) loss, hemorrhage, liver parenchymal cells death, nodular regeneration, Kupffer cells activation, and fibrogenesis occurred. These pathological changes classified the PAs-induced liver injury as acute, sub-acute, and chronic type. PAs metabolic activation, mitochondria injury, glutathione (GSH) depletion, inflammation, and LSECs damage-induced activation of the coagulation system were well recognized to play critical roles in the pathological process of PAs-induced hepatotoxicity. A lot of natural compounds like glycyrrhizic acid, (-)-epicatechin, quercetin, baicalein, chlorogenic acid, and so on were demonstrated to be effective in alleviating PAs-induced liver injury, which rendered them huge potential to be developed into therapeutic drugs for PAs poisoning in clinics. This review presents updated information about the diagnosis, toxicological mechanism, and detoxification studies on PAs-induced hepatotoxicity.

Gut microbiota dysbiosis induced by polychlorinated biphenyl 126 contributes to increased brain proinflammatory cytokines: Landscapes from the gut-brain axis and fecal microbiota transplantation

The pathogenesis of brain inflammation induced by polychlorinated biphenyl 126 (PCB126) has not yet been fully illustrated. Growing evidence highlights the relevance of the microbiota-gut-brain axis in central nervous system (CNS) dysfunction. Therefore, we aimed to study the role of the gut microbiota in PCB126-induced proinflammatory cytokine increases in the mouse brain. The results showed that PCB126 exposure significantly disordered gut bacterial communities, resulting in the enrichment of gram-negative bacteria (e.g., Bacteroidetes and Proteobacteria), further leading to elevated levels of the gram-negative bacterial lipopolysaccharide (LPS). Subsequently, colonic toll-like receptor 4 (TLR-4) was activated by bacterial LPS, which promoted proinflammatory cytokine generation and inhibited tight junction (TJ) protein expression. Then, bacterial LPS translocated from the gut lumen into the blood circulation and reached the brain, triggering LPS/TLR-4-mediated increases in brain proinflammatory cytokines. Further analysis after fecal microbiota transplantation (FMT) suggested that the gut microbiota disturbance caused by PCB126 could induce elevated bacterial LPS and trigger TLR-4-mediated increases in proinflammatory cytokines in the brain. This study highlights the possibility that PCB126-induced gut microbiota disorder contributes to increased brain proinflammatory cytokines. These results provide a new perspective for identifying the toxicity mechanisms of PCB126 and open up the possibility of modulating the gut microbiota as a therapeutic target for CNS disease caused by environmental pollution.

Screening for Susceptibility-Related Factors and Biomarkers of Xianling Gubao Capsule-Induced Liver Injury

Although increasing reports from the literature on herbal-related hepatotoxicity, the identification of susceptibility-related factors and biomarkers remains challenging due to idiosyncratic drug-induced liver injury (IDILI). As a well-known Chinese medicine prescription, Xianling Gubao Capsule (XLGB) has attracted great attention due to reports of potential liver toxicity. But the mechanism behind it is difficult to determine. In this paper, we found that XLGB-induced liver injury belongs to IDILI through the analysis of clinical liver injury cases. In toxicological experiment assessment, co-exposure to XLGB and non-toxic dose of lipopolysaccharide (LPS) could cause evident liver injury as manifested by significantly increased plasma alanine aminotransferase activity and obvious liver histological damage. However, it failed to induce observable liver injury in normal rats, suggesting that mild immune stress may be a susceptibility factor for XLGB-induced idiosyncratic liver injury. Furthermore, plasma cytokines were determined and 15 cytokines (such as IL-1β, IFN-γ, and MIP-2α etc) were acquired by receiver operating characteristic (ROC) curves analysis. The expression of these 15 cytokines in LPS group was significantly up-regulated in contrast to the normal group. Meanwhile, the metabolomics profile showed that mild immune stress caused metabolic reprogramming, including sphingolipid metabolism, phenylalanine metabolism, and glycerophospholipid metabolism. 8 potential biomarkers (such as sphinganine, glycerophosphoethanolamine, and phenylalanine etc.) were identified by correlation analysis. Therefore, these results suggested that intracellular metabolism and immune changes induced by mild immune stress may be important susceptibility mechanisms for XLGB IDILI.

Silencing of tissue factor by antisense deoxyoligonucleotide mitigates thioacetamide-induced liver injury

BACKGROUND

Retinoid receptors (RRs), RAR-α and RXR-α, work as transcription factors that regulate cell growth, differentiation, survival, and death. Hepatic stellate cells (HSCs) store retinoid and release its RRs as lipid droplets upon their activation.

PURPOSE

We test the hypothesis that loss of retinoid receptors RAR-α and RXR-α from HSCs is dependent on tissue factor (TF) during thioacetamide (TAA)-induced liver injury.

METHODS

Liver toxicity markers, TF, fibrin, cleaved caspase-3, and cyclin D1 as well as histopathology were investigated.

RESULTS

Increased TF, fibrin, cleaved caspase-3, and cyclin D1 protein expression is seen in zone of central vein after TAA injection compared with vehicle-treated mice. A strong downregulation of RAR-α and RXR-α is seen in TAA-induced liver injury. In addition, histopathological obliteration and pericentral expression of cleaved caspase 3 and cyclin D1 are observed after TAA injection compared with the normal vehicle-treated mice. No changes have been seen in TAA/TF-sense (SC) in whole parameters compared with TAA-treated animals. TAA/TF-antisense (AS)-treated mice show normal expression of all parameters and normal histopathological features when compared with the control mice. In conclusion, this study declares that the strong downregulation of RAR-α and RXR-α may cause liver injury and particularly activation of HSCs in TAA-induced toxicity. TF-AS treatment not only downregulates TF protein expression but also alleviates loss of liver RAR-α and RXR-α and suppresses the activated apoptosis signals in TAA-induced liver toxicity. Finally, TF and RAR-α/RXR-α are important regulatory molecules in TAA induced acute liver injury.

Protective Effects of Dracocephalum heterophyllum in ConA-Induced Acute Hepatitis

Dracocephalum heterophyllum (DH) is a Chinese herbal medicine used in treating hepatitis. However, the protective effects and pharmacological mechanisms of DH in hepatitis are unknown. In this study, we found that pretreatment with DH extract significantly ameliorated liver injury and suppressed the production of inflammatory cytokines, including tumor necrosis factor (TNF-α) and interferon-γ (IFN-γ) in Concanavalin A- (ConA-) induced hepatitis (CIH). DH recruited more CD11b⁺ Gr1⁺ myeloid-derived suppressor cells (MDSCs) to the liver and suppressed infiltration of macrophages (Kupffer cells) in the liver. The present work explores DH as an effective hepatoprotective medicine to inhibit inflammation and liver injury caused by hepatitis.

Gut microbiota disturbance and non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD), also called fatty liver, is the most common chronic liver disease. Although the prevalence of NAFLD is increasing, the mechanisms underlying its pathogenesis are incompletely understood. So far, there has been no effective approach for its prevention and treatment. With the development of next generation sequencing technology, recent studies have shown that gut microbiota alterations including changes in the composition of gut flora, bacterial translocation and small intestinal bacterial overgrowth, play roles in the development of NAFLD. Besides destruction of the intestinal barrier, the most important pathogenic mechanism of gut microbiota distrubance is the facilitation of bacteria and their toxic products to reach the liver through the gut liver-axis. The hepatic immune system is activated through pattern recognition receptors, such as Toll-like and NOD-like receptor signaling pathways. The release of pro-inflammatory cytokines including tumor necrosis factor and interleukins results in liver injury, which progresses to NAFLD. Application of probiotics, antibiotics and fecal microbiota transplantation has shown efficiency, which provides new targets for the prevention and treatment of NAFLD.

Antifibrotic effect of heparin on liver fibrosis model in rats

AIM

To evaluate the effect of chronic thrombin inhibition by heparin on experimentally induced chronic liver injury (liver fibrosis) in rats.

METHODS

Chronic liver injury (liver fibrosis) was induced in Wistar rats by oral administration of carbon tetrachloride (CCl4) for 7 wk, an animal model with persistent severe hepatic fibrosis. Intravenous administration of the thrombin antagonist (heparin) started 1 wk after the start of CCl4 intoxication for 6 wk. After completion of treatment (7 wk), markers of hepatic dysfunction were measured and changes evaluated histopathologically.

RESULTS

Higher serum glutamate oxaloacetate transaminase (SGOT), serum glutamate pyruvate transaminase (SGPT), alkaline phosphatase (ALP), total, direct and indirect bilirubin levels, as well as lower fibrinogen levels, were found in CCl4 intoxicated rats. Heparin, silymarin and combination of drug (heparin and silymarin) treatment for 6 wk prevented a rise in SGOT, SGPT, ALP, total, direct and indirect bilirubin levels and improved fibrinogen levels. Deterioration in hepatic function determined by the fibrosis area was retarded, as evident from hepatic histopathology. Total protein levels were not changed in all groups.

CONCLUSION

Heparin, a thrombin antagonist, preserved hepatic function and reduced severity of hepatic dysfunction/fibrogenesis. Combination of heparin and silymarin produced additional benefits on liver fibrosis.

Antifibrotic effect of heparin on liver fibrosis model in rats

AIM: To evaluate the effect of chronic thrombin inhibition by heparin on experimentally induced chronic liver injury (liver fibrosis) in rats.

METHODS: Chronic liver injury (liver fibrosis) was induced in Wistar rats by oral administration of carbon tetrachloride (CCl₄) for 7 wk, an animal model with persistent severe hepatic fibrosis. Intravenous administration of the thrombin antagonist (heparin) started 1 wk after the start of CCl₄ intoxication for 6 wk. After completion of treatment (7 wk), markers of hepatic dysfunction were measured and changes evaluated histopathologically.

RESULTS: Higher serum glutamate oxaloacetate transaminase (SGOT), serum glutamate pyruvate transaminase (SGPT), alkaline phosphatase (ALP), total, direct and indirect bilirubin levels, as well as lower fibrinogen levels, were found in CCl₄ intoxicated rats. Heparin, silymarin and combination of drug (heparin and silymarin) treatment for 6 wk prevented a rise in SGOT, SGPT, ALP, total, direct and indirect bilirubin levels and improved fibrinogen levels. Deterioration in hepatic function determined by the fibrosis area was retarded, as evident from hepatic histopathology. Total protein levels were not changed in all groups.

CONCLUSION: Heparin, a thrombin antagonist, preserved hepatic function and reduced severity of hepatic dysfunction/fibrogenesis. Combination of heparin and silymarin produced additional benefits on liver fibrosis.

Intervention effect of microbiological capsules containing Bacillus subtilis and Enterococcus on intestinal flora in patients with NASH

AIM: To investigate the interventional effect of microbiological capsules (Medilac-S) containing Bacillus subtilis and Enterococcus on intestinal flora in patients with nonalcoholic steatohepatitis (NASH).

METHODS: Thirty healthy adults and sixty patients with NASH were included, and they were divided into three groups: group A (30 healthy adults, control group), group B (30 patients, treated with basic drugs), and group C (30 patients, treated with basal drugs and Medilac-S). Eight types of representative bacteria of the intestinal flora were cultivated and counted, and the levels of serum endotoxin, TNF-α, IL-6 and ALT was determined in all groups before treatment and 4 wk after treatment.

RESULTS: Compared to group A, the numbers of Bacillus bifidus, Bacillus lactis and Bacteroides decreased (7.13 ± 1.28 vs 8.83 ± 1.24, t = -6.65, P < 0.01; 6.67 ± 1.21 vs 7.31 ± 1.12, t = -2.16, P < 0.05; 6.99 ± 1.31 vs 7.82 ± 1.15, t = -2.41, P < 0.05), that of Enterobacteria increased (7.28 ± 1.22 vs 6.54 ± 1.08, t = 4.83, P < 0.01), and serum levels of endotoxin, IL-6 and TNF-α increased (168.37 EU/L ± 24.13 EU/L vs 110.53 EU/L ± 18.33 EU/L, t = 11.69, P < 0.01; 42.62 ng/L ± 12.65 ng/L vs 21.58 ng/L ± 8.47 ng/L, t = 7.71, P < 0.01; 15.98 ng/L ± 3.19 ng/L vs 8.63 ng/L ± 2.49 ng/L, t = 11.97, P < 0.01) in patients with NASH (groups B and C) before the treatment. After 4 weeks of treatment, the numbers of Bacillus bifidus, Bacillus lactis and Bacteroides increased significantly (all P < 0.01), that of Enterobacteria decreased (P < 0.05), and serum levels of endotoxin, TNF-α, IL-6 and ALT decreased remarkably (P < 0.05) in group C but not in group B compared to group A. The clinical symptoms were improved more apparently in group C than in group B.

CONCLUSION: Alteration of intestinal flora and overgrowth of Gram-negative bacilli probably participate in the development of NASH. Medilac-S can effectively improve intestinal flora, decrease serum levels of endotoxin, TNF-α, IL-6 and ALT, and improve clinical symptoms in patients with NASH.

Tissue factor antisense deoxyoligonucleotide prevents monocrotaline/LPS hepatotoxicity in mice

Tissue factor (TF) is a membranous glycoprotein that functions as a receptor for coagulation factor VII/VIIa and activates the coagulation system when blood vessels or tissues are damaged. TF was upregulated in our monocrotaline (MCT)/lipopolysaccharide (LPS) hepatotoxicity model. We tested the hypothesis that TF-dependent fibrin deposition and lipid peroxidation in the form of oxidized low-density-lipoprotein (ox-LDL) accumulation contribute to liver inflammation induced by MCT/LPS in mice. In the present study, we blocked TF using antisense oligodeoxynucleotides against mouse TF (TF-ASO). TF-ASO (5.6 mg kg(-1) ) was given i.v. to ND4 male mice 30 min after administration of MCT (200 mg kg(-1) ) p.o. followed after 3.5 h by LPS i.p. (6 mg kg(-1) ). Blood alanine aminotransferase (ALT), TF, ox-LDL, platelets, hematocrit and keratinocyte-derived chemokine (KC) levels were evaluated in different treatment groups. Fibrin deposition and ox-LDL accumulation were also analyzed in the liver sections using immunofluorescent staining. The results showed that TF-ASO significantly restored blood ALT, hematocrit and KC levels, distorted after MCT/LPS co-treatment, as well as preventing the accumulation of ox-LDL and the deposition of fibrin in the liver tissues, and thereby inhibited liver injury caused by MCT/LPS. In a separate experiment, TF-ASO administration significantly prolonged animal survival. The current study demonstrates that TF is associated with MCT/LPS-induced liver injury. Administration of TF-ASO successfully prevented this type of liver injury.

Tissue factor dependent liver injury causes release of retinoid receptors (RXR-α and RAR-α) as lipid droplets

Hepatic stellate cells (HSC) store retinoids and upon activation differentiate into myofibroblast-like cells, a process whereby they lose their retinoid-containing lipid droplets. We reported earlier, activation of tissue factor (TF) in our MCT/LPS hepatotoxicity model. We now report the involvement of TF in the release of retinoid receptors RAR-α and RXR-α as accumulated lipid droplet during monocrotaline/lipopolysaccharide (MCT/LPS)-liver injury. Constitutive expression of RAR-α was observed in HSCs and endothelial cells of bile duct and portal vein, while expression of RXR-α was observed in certain pericentral hepatocytes and HSCs. Administration of sub-toxic doses of MCT or LPS strongly increased TF and RXR-α but not RAR-α expressions in HSCs and hepatocytes. However MCT/LPS co-treatment showed insoluble droplets containing RAR-α and RXR-α in the vicinity of the necrotic areas. Blocking TF with TF antisense oligonucleotides (TF-AS ODN) led to normal hepatocyte expression of RXR-α and upregulated the expression of RAR-α in HSCs. This study shows clear evidence of in vivo release of RAR-α and RXR-α as insoluble lipid droplets in liver injury. It is possible that these insoluble droplets of RAR-α and RXR-α could be used as markers for liver injury in general and activation of HSCs in particular. RXR-α appears to be a more sensitive than RAR-α as it was affected by even the subtoxic doses of MCT or LPS. The fact that TF-AS treatment not only down-regulated TF but also obliterated the release of RAR-α and RXR-α as insoluble lipid droplets in hepatocytes points towards TF being an important regulatory molecule for RAR-α and RXR-α.

Noncirrhotic portal hypertension in HIV-infected patients: a case control evaluation and review of the literature

Idiopathic noncirrhotic portal hypertension (NCPH) is an infrequent but possibly underestimated cryptogenetic liver disease recently described in small series of HIV-infected patients. The exposure to antiretroviral drugs, a direct role of HIV itself, microbial translocation from the gut, or a thrombophilic propensity have been suggested as possible pathogenic mechanisms. In this case control study, we describe 11 HIV-infected patients with idiopathic NCPH and compare the activity of protein C and S, and soluble CD14 levels (a surrogate marker of the translocation of intestinal bacterial products) with 10 age- and gender-matched HIV-infected controls with no liver disease. The clinical presentation of the 11 patients with NCPH was characterised by acute variceal bleeding (2/11), ascites (2/11), portal thrombosis (2/11), and ultrasonographic and endoscopic signs of portal hypertension (11/11), with slightly high alanine transaminase (ALT) and γglutamyl transpeptidase (γ-GT) levels. The FibroScan median liver stiffness was 8.1 kPa, which is inconsistent with significant fibrosis, and nodular regenerative hyperplasia was diagnosed in the 5 patients who underwent liver biopsy. The NCPH patients showed no impairment of hepatic synthesis, but had lower serum albumin levels and a higher international normalized ratio (INR) than the controls (p = 0.01), and lower protein C and S activity, although within the normal range (p = 0.02 and 0.3, respectively). No significant difference in soluble CD14 was seen between the two groups. In conclusion, the etiology of NCHP is not still established, but in order to prevent the dramatic complications of portal hypertension, all HIV-infected patients with unexplained liver enzyme abnormalities or thrombocytopenia should be considered for further investigations by means of thrombophilic screening, Doppler ultrasound evaluation, and in the presence of portal hypertension, endoscopy and liver biopsy.

Role of Kupffer cells in the pathogenesis of endotoxin-induced liver injury

Endotoxin (lipopolysaccharide, LPS)-induced liver injury was involved in the initiation and development of various liver diseases, and liver macrophages (Kupffer cells) were demonstrated to play important roles in these processes. On one hand, Kupffer cells were activated to release pro-inflammatory factors via the system of LPS-induced signal transduction, and this responsibility was also cooperated by the interaction of other liver cells to mediate liver injury. On the other hand, the activation of Kupffer cells were also inhibited by LPS tolerance and other physiological regulatory mechanisms, which prevented the liver injury mediated by Kupffer cells. Thus, Kupffer cells were simultaneously co-stimulated by factors of activation and inhibition to keep a relative balance. LPS-induced liver injury may occur once the balance is pathologically broken, whereas inhibitory intervention of Kupffer cells' activation is a key strategy to protect the LPS-induced injury.

Coagulation-dependent gene expression and liver injury in rats given lipopolysaccharide with ranitidine but not with famotidine

In an animal model of drug idiosyncrasy, rats cotreated with nonhepatotoxic doses of lipopolysaccharide (LPS) and ranitidine (RAN) develop hepatocellular injury, whereas rats treated with LPS and famotidine (FAM) do not. The coagulation system and neutrophils (PMNs) are requisite mediators of LPS/RAN-induced liver injury. We tested the hypothesis that unique gene expression in LPS/RAN-treated rats requires coagulation system activation and that these changes are absent in rats given LPS and FAM. Rats were treated with a nonhepatotoxic dose of LPS (44.4 x 10(6) endotoxin units/kg i.v.) or its vehicle, and then 1 h later, they were treated with heparin (3000 U/kg) or its vehicle. One hour thereafter, they were given RAN (30 mg/kg), FAM (6 mg/kg, a pharmacologically equiefficacious dose, or 28.8 mg/kg, an equimolar dose), or vehicle (i.v.). They were killed 2 or 6 h after drug treatment for evaluation of hepatotoxicity, coagulation system activation, and liver gene expression (2 h only). Statistical filtering of gene array results and real-time polymerase chain reaction identified groups of genes expressed in LPS/RAN-treated rats but not LPS/FAM-treated rats that were either changed or unchanged by heparin administration. For example, LPS/RAN-induced mRNA expression of the inflammatory mediators interleukin-6, cyclooxygenase-2, and macrophage inflammatory protein-2 (MIP-2) was reduced by anticoagulation. Enhancement of serum MIP-2 and plasminogen activator inhibitor-1 concentrations in LPS/RAN-treated rats was prevented by anticoagulation. The results suggest cross-talk between hemostasis-induced gene expression and inflammation (e.g., PMN function) in the genesis of hepatocellular injury in LPS/RAN-treated rats. In contrast, neither the expression of such genes nor hepatocellular necrosis occurred in rats treated with LPS/FAM.

Coagulation-Mediated Hypoxia and Neutrophil-Dependent Hepatic Injury in Rats Given Lipopolysaccharide and Ranitidine

Idiosyncrasy-like liver injury occurs in rats cotreated with nonhepatotoxic doses of ranitidine (RAN) and bacterial lipopolysaccharide (LPS). Hepatocellular oncotic necrosis is accompanied by neutrophil (PMN) accumulation and fibrin deposition in LPS/RAN-treated rats, but the contribution of PMNs to injury has not been shown. We tested the hypothesis that PMNs are critical mediators of LPS/RAN-induced liver injury and explored the potential for interaction between PMNs and hemostasis-induced hypoxia. Rats were given either LPS (44.4 x 10(6) endotoxin units/kg) or its vehicle and then RAN (30 mg/kg) or its vehicle 2 h later. They were killed 3 or 6 h after RAN treatment, and hepatocellular injury was estimated from serum alanine aminotransferase activity and liver histopathology. Plasma PMN chemokine concentration and the number of PMNs in liver increased after LPS treatment at 3 h and were not markedly altered by RAN cotreatment. Depletion of circulating PMNs attenuated hepatic PMN accumulation and liver injury and had no effect on coagulation system activation. Anticoagulation with heparin attenuated liver fibrin deposition and injury in LPS/RAN-treated rats; however, heparin had little effect on liver PMN accumulation or plasma chemokine concentration. Liver hypoxia occurred in LPS/RAN-cotreated rats and was significantly reduced by heparin. In vitro, hypoxia enhanced the killing of rat hepatocytes by PMN elastase and shortened its onset, indicating a synergistic interaction between PMNs and hypoxia. The results suggest that PMNs are involved in the hepatocellular injury caused by LPS/RAN-cotreatment and that hemostasis increases sensitivity to PMN-induced hepatocellular injury by causing liver hypoxia.

Role of hepatic fibrin in idiosyncrasy-like liver injury from lipopolysaccharide-ranitidine coexposure in rats

Coadministration of nonhepatotoxic doses of the histamine 2-receptor antagonist ranitidine (RAN) and bacterial lipopolysaccharide (LPS) results in hepatocellular injury in rats, the onset of which occurs in 3 to 6 hours. This reaction resembles RAN idiosyncratic hepatotoxicity in humans. Early fibrin deposition occurs in livers of rats cotreated with LPS/RAN. Accordingly, we tested the hypothesis that the hemostatic system contributes to liver injury in LPS/RAN-treated rats. Rats were given either LPS (44.4 x 10(6) EU/kg) or its vehicle, then RAN (30 mg/kg) or its vehicle 2 hours later. They were killed 2, 3, 6, 12, or 24 hours after RAN treatment, and liver injury was estimated from serum alanine aminotransferase activity. A modest elevation in serum hyaluronic acid, which was most pronounced in LPS/RAN-cotreated rats, suggested altered sinusoidal endothelial cell function. A decrease in plasma fibrinogen and increases in thrombin-antithrombin dimers and in serum concentration of plasminogen activator inhibitor-1 occurred before the onset of liver injury. Hepatic fibrin deposition was observed in livers from LPS/RAN-cotreated rats 3 and 6 hours after RAN. Liver injury was abolished by the anticoagulant heparin and was significantly attenuated by the fibrinolytic agent streptokinase. Hypoxia, one potential consequence of sinusoidal fibrin deposition, was observed in livers of LPS/RAN-treated rats. In conclusion, the results suggest that the hemostatic system is activated after LPS/RAN cotreatment and that fibrin deposition in liver is important for the genesis of hepatic parenchymal cell injury in this model.

Adverse hepatic drug reactions: inflammatory episodes as consequence and contributor

Susceptibility to drug toxicity is influenced by a variety of factors, both genetic and environmental. The focus of this article is the evidence addressing the hypothesis that inflammation is both a result of and a susceptibility factor for drug toxicity, with an emphasis on liver as a target organ. Results of studies suggesting a role for inflammatory mediators in the hepatotoxicity caused by acetaminophen or ethanol are discussed. For several drugs, the evidence from animal models that concurrent inflammation increases injury is presented. In addition, the occurrence of adverse drug reactions in people with preexisting inflammatory diseases is considered. The special case of idiosyncratic drug reactions is discussed and the potential raised for development of animal models for this type of drug toxicity. The conclusion is that inflammatory factors should be considered as determinants of sensitivity to adverse drug reactions.

Intoxicação por Crotalaria retusa (Fabaceae) em Eqüídeos no semi-árido da Paraíba

De 2000 a 2003 oito casos de intoxicação por Crotalaria retusa L. foram observados em eqüinos em 8 fazendas na região semi-árida da Paraíba e do Ceará. C. retusa foi encontrada no pasto em todas as propriedades. Os principais sinais clínicos foram característicos de encefalopatia hepática, com apatia ou hiperexcitabilidade, pressão da cabeça, andar compulsivo ou em círculo e, ocasionalmente, galope descontrolado e violento. Decréscimo nos reflexos dos nervos craniais, ataxia e fraqueza foram também observados. Outros sinais clínicos foram anorexia, perda de peso, fotossensibilização e icterícia. O curso clínico variou de 4 a 40 dias, mas muitos cavalos tinham um histórico prévio de perda de peso. À necropsia os fígados eram duros, com superfície irregular e áreas brancas misturadas com áreas vermelho-escuras e com aumento no padrão lobular. Icterícia moderada, ascite, hidropericárdio e hidrotorax foram também observados. Edema e moderada congestão foram observadas nos pulmões. As lesões histológicas do fígado foram caracterizadas por fibrose, principalmente periportal, megalocitose e proliferação de células dos ductos biliares. Áreas multifocais de hemorragias centrolobulares ou mediozonais foram também observadas. Necrose hemorrágica centrolobular estava presente em dois eqüinos. Foram observados astrócitos Alzheimer tipo II, isolados ou em grupos principalmente no núcleo caudato e córtex em 4 eqüinos. A intoxicação foi produzida experimentalmente em 1 eqüino e 3 asininos. O eqüino adulto, recebeu diariamente, 100 g de sementes de C. retusa e morreu aos 52 dias após o início do experimento. C. retusa inteira, seca foi misturada com capim e dada a 3 asininos adultos em doses diárias de 10 g/kg, 5 g/kg e 2,5 g/kg respectivamente. O asinino tratado com 5 g/kg morreu aos 48 dias após o início do experimento e os outros dois foram sacrificados aos 120 dias. Os sinais clínicos e a patologia foram similares aos observados nos casos espontâneos, alguns astrócitos Alzheimer tipo II foram observados somente no asinino que morreu após 48 dias do inicio da ingestão. A concentração de monocrotalina na planta inteira administrada aos asininos foi 0,5%.

Workshop Overview: Hepatotoxicity Assessment for Botanical Dietary Supplements

Botanical dietary supplements (herbal products) have flooded the market in the United States over the past decade, and studies show a significant percentage of Americans use them. With increasing frequency and duration of exposure, some serious adverse effects, though relatively uncommon, have been reported. Among the most troublesome is the association of some botanicals with serious hepatotoxicity. In some cases, hepatotoxicity has been linked to the consumption of botanicals with recognized hepatotoxic components (e.g., pyrrolizidine alkaloids). However, in other cases, the causative agent(s) is less clear and, overall, the mechanisms of hepatotoxicity are poorly understood. To help create a scientific basis for understanding botanical-induced hepatotoxicity and better tools for hepatotoxicity assessment and prediction, the National Center for Natural Product Research (NCNPR) hosted a workshop (September 8 and 9, 2003) in cooperation with the Center for Food Safety and Applied Nutrition (CFSAN) of the Food and Drug Administration (FDA). The workshop featured presentations by 22 experts and was attended by 65 individuals. The agenda can be found in the supplementary data at www.toxsci.oupjournals.org.

Hyperplasia, partial hepatectomy, and the carcinogenicity of aflatoxin B1

Generalized cellular hyperplasia has long been associated as a factor in the causation of liver cancer. Parenchymal cell hyperplasia resulting from hepatotoxins, viruses, parasites, or malnutrition is exceedingly variable as to when it occurs, its extent, and its duration. Partial hepatectomy has been used as an experimental tool precisely because the timing and extent of hyperplasia can be known and controlled. With regards to aflatoxin B1 (AFB1) carcinogenesis, partial hepatectomy has produced variable results. An explanation appears to reside in the hepatotoxic properties of AFB1 that enhance the early stages of carcinogenesis.