NF-kappa B, liposomes and pathogenesis of hepatic injury and fibrosis

Liver regeneration in traditional Chinese medicine: advances and challenges

Liver diseases pose a serious problem for national health care system all over the world. Liver regeneration has profound impacts on the occurrence and development of various liver diseases, and it remains an extensively studied topic. Although current knowledge has suggested two major mechanisms for liver regeneration, including compensatory hyperplasia of hepatocytes and stem or progenitor cell-mediated regeneration, the complexity of this physiopathological process determines that its effective regulation cannot be achieved by single-target or single-component approaches. Alternatively, using traditional Chinese medicine (TCM) to regulate liver regeneration is an important strategy for prevention and treatment of liver disorder and the related diseases. From the perspectives of TCM, liver regeneration can be caused by the disrupted balance between hepatic damage and regenerative capacity, and the "marrow"-based approaches have important therapeutic implications for liver regeneration. These two points have been massively supported by a number of basic studies and clinical observations during recent decades. TCM has the advantages of overall dynamic fine-tuning and early adjustment, and has exhibited enormous therapeutic benefits for various liver diseases. Here, we review the recent advances in the understanding of liver regeneration in TCM system in the hope of facilitating the application of TCM for liver diseases via regulation of liver regeneration.

Anti-fibrotic role and mechanism of Periplaneta americana extracts in CCl4-induced hepatic fibrosis in rats

Hepatic fibrosis is resulted from sustained wound-healing responses to various harmful stimuli, including viral infection, drug toxicity, alcohol, and autoimmune hepatopathy, and it has recently attracted the attention of an increasing number of researchers and clinical workers. The aims of this study were to examine the anti-fibrotic effects of extracts of Periplaneta americana (EPA) on CCl4-induced hepatic fibrosis in rats, to preliminary determine the anti-fibrotic efficacy of EPA, and to identify a potential and effective therapeutic agent to attenuate hepatic fibrosis. In this study, we routinely detected liver functional indices, such as alanine aminotransferase (ALT), aspartate transaminase (AST), and albumin (Alb). We also measured hepatic fibrosis-related serum markers, including hyaluronic acid (HA), laminin (LN), type III procollagen (PC III), and type IV collagen (IV-C) via radioimmunoassay. Moreover, we examined histological activity and fibrosis stage via light microscopy after hematoxylin and eosin and Masson staining. Furthermore, we detected the expressions of nuclear factor-kappa B (NF-κB), alpha-smooth muscle actin (α-SMA), transforming growth factor-β1 (TGF-β1), and tissue inhibitor of metalloprotease-1 (TIMP-1) in rat liver tissues by immunohistochemical staining. We found that EPA, whose main components are viscous sugar amino acids, can reduce the levels hepatic fibrosis-related factors, including HA, LN, PC III, and IV-C, improve liver function, attenuate, or reverse pathological damage associated with hepatic fibrosis, and thus inhibit the progression of hepatic fibrosis. The mechanism of EPA action may be related to the inhibition of TGF-β1, NF-κB, and α-SMA expressions and the reduction of TIMP-1 levels in the liver to reduce the accumulation of extracellular matrix (ECM) components, thereby blocking the relevant signaling pathways and preventing inflammatory responses to attenuate or reverse hepatic fibrosis. EPA may thus be used as a potentially effective therapeutic agent for the treatment of hepatic fibrosis.

中医药调控肝再生的研究进展及展望

中医药调控肝再生是防治肝病及其相关病证的重要策略, 已形成的研究热点方兴未艾. 近些年来取得的主要进展至少包括以下几个方面: 调控肝损伤与肝再生失衡提高了中医/中西医结合防治肝病及其相关病证的临床疗效, "髓"为中心治疗靶点的研究进展揭示了中医/中西医结合防治肝病及其相关病证的疗效机制, 整体动态微调早调的作用方式满足了肝再生调控复杂多变的需要, 解决了单靶点调控肝再生疗效有限的关键科学问题, 平衡协调的疗效考核与结局指标的综合判断为中医药调控肝再生的临床推广应用提供了途径和方法.

Time course of gene expression profiling in the liver of experimental mice infected with Echinococcus multilocularis

BACKGROUND

Alveolar echinococcosis (AE) is a severe chronic parasitic disease which behaves like a slow-growing liver cancer. Clinical observations suggest that the parasite, Echinococcus multilocularis (E. multilocularis) influences liver homeostasis and hepatic cell metabolism. However, this has never been analyzed during the time course of infection in the common model of secondary echinococcosis in experimental mice.

METHODOLOGY/PRINCIPAL FINDINGS

Gene expression profiles were assessed using DNA microarray analysis, 1, 2, 3 and 6 months after injection of E. multilocularis metacestode in the liver of susceptible mice. Data were collected at different time points to monitor the dynamic behavior of gene expression. 557 differentially expressed genes were identified at one or more time points, including 351 up-regulated and 228 down-regulated genes. Time-course analysis indicated, at the initial stage of E. multilocularis infection (month 1-2), that most of up-regulated pathways were related to immune processes and cell trafficking such as chemokine-, mitogen-activated protein kinase (MAPK) signaling, and down-regulated pathways were related to xenobiotic metabolism; at the middle stage (month 3), MAPK signaling pathway was maintained and peroxisome proliferator-activated receptor (PPAR) signaling pathway emerged; at the late stage (month 6), most of up-regulated pathways were related to PPAR signaling pathway, complement and coagulation cascades, while down-regulated pathways were related to metabolism of xenobiotics by cytochrome P450. Quantitative RT-PCR analysis of a random selection of 19 genes confirmed the reliability of the microarray data. Immunohistochemistry analysis showed that proliferating cell nuclear antigen (PCNA) was increased in the liver of E. multilocularis infected mice from 2 months to 6 months.

CONCLUSIONS

E. multilocularis metacestode definitely exerts a deep influence on liver homeostasis, by modifying a number of gene expression and metabolic pathways. It especially promotes hepatic cell proliferation, as evidenced by the increased PCNA constantly found in all the experimental time-points we studied and by an increased gene expression of key metabolic pathways.

Protective effect of glycoprotein isolated from Ulmus davidiana Nakai on carbon tetrachloride-induced mouse liver injury

This study was carried out to evaluate the hepatoprotective activity of glycoprotein isolated from the stems of Ulmus davidiana Nakai (UDN), which has been used as an anti-inflammatory agent in folk medicine. We evaluated lipid peroxidation in glucose/glucose oxidase (G/GO)-induced BNL CL.2 cells and measured thiobarbituric acid reactive substances (TBARS), lactate dehydrogenase (LDH), nitric oxide (NO), antioxidant enzyme (superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx)), activity of cytotoxic-related signals (hepatic cytochrome c, nuclear factor-kappa B (NF-κB) and activator protein-1 (AP-1)) and levels of plasma lipids (triglyceride (TG) and total cholesterol (TC)) in carbon tetrachloride (CCl4, 1.0 mL kg−1)-induced A/J mouse. The results in G/GO-induced BNL CL.2 cells showed that UDN glycoprotein had a dose-dependent inhibitory effect on lipid peroxidation. The results in carbon tetrachloride (CCl4, 1.0 mL kg−1)-induced A/J mouse indicated that treatment with UDN glycoprotein (40 mg kg−1) lowered LDH activity and TBARS formation, and increased NO production and antioxidant enzymes activity, compared with control. Also, our finding from CCl4-treated mice after pretreatment with UDN glycoprotein demonstrated that the activity of cytotoxic-related signals decreased but the levels of plasma lipids increased, compared with CCl4 treatment alone. Here, we speculate that UDN glycoprotein has a protective character to CCl4-induced mouse liver injury.

HEPATOPROTECTIVE AND HYPOLIPIDAEMIC EFFECTS OF GLYCOPROTEIN ISOLATED FROM GARDENIA JASMINOIDES ELLIS IN MICE

The present study was performed to investigate the hepatoprotective and hypolipidaemic effects of a 27 kDa glycoprotein isolated from Gardenia jasminoides Ellis (GJE glycoprotein) in glucose/glucose oxidase (G/GO)-treated BNL CL.2 cells, as well as in CCl4, Triton WR-1339 and corn oil-treated mice. In G/GO-treated BNL CL.2 cells, the results showed that GJE glycoprotein has an inhibitory effect on G/GO-induced cytotoxicity and intracellular reactive oxygen species production. In addition, GJE glycoprotein has an anti-oxidant effect against the lipid peroxidation process in the Fe2+/ascorbic acid system. In CCl4 (1.0 mL/kg)-treated mice, pretreatment with GJE glycoprotein (80 mg/kg) blocked lactate dehydrogenase release and the formation of thiobarbituric acid-reactive substances. In addition, in these mice GJE resulted in increased nitric oxide production and the activation of anti-oxidant enzymes, accompanied by the inhibition of the cytotoxic-related signals hepatic cytochrome c, nuclear factor-kappaB and activator protein-1. In both Triton WR-1339 (400 mg/kg) and corn oil (1.0 g/kg)-treated mice, pretreatment with GJE glycoprotein (80 mg/kg) lowered the levels of plasma lipoproteins (triglyceride, total cholesterol and low-density lipoprotein). On the basis of these results, we assume that GJE glycoprotein can ameliorate liver function, because it has hepatoprotective and hypolipidaemic activities.

Rhus verniciflua Stokes glycoprotein (36kDa) has protective activity on carbon tetrachloride-induced liver injury in mice

This study was carried out to investigate the hepatoprotective effect of the glycoprotein isolated from Rhus verniciflua Stokes (RVS), which has traditionally been used for healing of inflammatory diseases. We evaluated the activities of alanine aminotransferase (ALT), lactate dehydrogenase (LDH), thiobarbituric acid-reactive substances (TBARS), and antioxidant enzymes [superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx)] activities in treatment with carbon tetrachloride (CCl(4)) in vivo. When mice were treated with CCl(4) in the absence of RVS glycoprotein, the activities of ALT, LDH, and TBARS were increased, while the antioxidant enzymes activities were decreased. However, when the mice were treated with CCl(4) in the presence of RVS glycoprotein, the activities of ALT, LDH, and TBARS were significantly reduced and SOD, CAT, and GPx activities were remarkably increased. In addition, RVS glycoprotein increased the nitric oxide (NO) production and decreased the nuclear factor-kappa B (NF-κB) and activator protein-1 (AP-1) activation in CCl(4)-treated mice. Collectively, these results pointed out that RVS glycoprotein can inhibit lipid peroxidation, enhance the activities of antioxidant enzymes, increase the NO production, and decrease the NF-κB and AP-1 activations. Therefore, we speculate that RVS glycoprotein protects from liver damage through its radical scavenging ability.

1,2,3,4,6-penta-O-galloyl-β-D-glucose up-regulates heme oxygenase-1 expression by stimulating Nrf2 nuclear translocation in an extracellular signal-regulated kinase-dependent manner in HepG2 cells

AIM: To examine the potency of 1,2,3,4,6-penta-O-galloyl-β-D-glucose (PGG) as a hepatic heme oxygenase-1 (HO-1) inducer and its regulation in HepG2 cells.

METHODS: Expression of HO-1 and NF-E2-related factor 2 (Nrf2) and activation of mitogen-activated protein (MAP) kinases were analyzed by Western blot, immunofluorescence assay, and flow cytometry. Transfections of HO-1 gene, small interfering RNAs for HO-1 and Nrf2, and dominant-negative gene for MAP/extracellular signal-regulated kinase (ERK) were carried out to dissect the signaling pathways leading to HO-1 expression in HepG 2 cells.

RESULTS: PGG up-regulated HO-1 expression and this expression conferred cytoprotection against oxidative injury induced by t-butyl hydroperoxide. Moreover, PGG induced Nrf2 nuclear translocation, which was found to be an upstream step of PGG-induced HO-1 expression, and ERK activation, of which pathway was involved in PGG-induced Nrf2 nuclear translocation, HO-1 expression and cytoprotection.

CONCLUSION: PGG up-regulates HO-1 expression by stimulating Nrf2 nuclear translocation in an ERK-dependent manner, and HO-1 expression by PGG may serve as one of the important mechanisms for its hepatoprotective effects.

Glycoprotein Isolated From Ulmus davidiana NAKAI Protects Against Carbon Tetrachloride-Induced Liver Injury in the Mouse

Ulmus davidiana NAKAI (UDN) has traditionally been used for healing of inflammatory diseases. This study was carried out to investigate the hepatoprotective effect of the glycoprotein isolated from UDN in carbon tetrachloride (CCl4)-induced liver injury. We evaluated the activities of alanine aminotransferase (ALT), lactate dehydrogenase (LDH), thiobarbituric acid-reactive substances (TBARS), and antioxidant enzymes [superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx)] activities in CCl4-treated mice. When mice were treated with CCl4 in the absence of UDN glycoprotein, the activities of ALT, LDH, and TBARS were increased, while the antioxidant enzymes activities were decreased. However, when the mice were treated with CCl4 in the presence of UDN glycoprotein, the activities of ALT, LDH, and TBARS were significantly reduced and SOD, CAT, and GPx activities were remarkably increased. In addition, UDN glycoprotein increased the nitric oxide production and decreased the nuclear factor-kappa B and activator protein-1 activation in CCl4-treated mice. We also investigated the protective effects of UDN glycoprotein in glucose/glucose oxidase (G/GO)-induced cytotoxicity in primary cultured mouse hepatocytes. UDN glycoprotein markedly inhibited the cell death induced by G/GO. These results suggest that UDN glycoprotein protects against CCl4-induced liver injury in the mouse.

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Concurrent inflammation as a determinant of susceptibility to toxicity from xenobiotic agents

Sensitivity to the toxic effects of xenobiotic agents is influenced by a number of factors. Recent evidence derived from studies using experimental animals suggests that inflammation is one of these factors. For example, induction of inflammation by coexposure to bacterial endotoxin, vitamin A or Corynebacterium parvum increases injury in response to a number of xenobiotic agents that target liver. These agents are diverse in chemical nature and in mechanism of hepatotoxic action. Factors critical to the augmentation of liver injury by inflammation include Kupffer cells, neutrophils, cytokines such as tumor necrosis factor-alpha (TNF-alpha) and lipid mediators such as prostaglandins, but these may vary depending on the xenobiotic agent and the mechanisms by which it alters hepatocellular homeostasis. In addition, the timing of inflammagen exposure can qualitatively alter the toxic response to chemicals. Inflammation-induced increases in susceptibility to toxicity are not limited to liver. Concurrent inflammation also sensitizes animals to the toxic effects of agents that damage the respiratory tract, kidney and lymphoid tissue. It is concluded that inflammation should be considered as a determinant of susceptibility to intoxication by xenobiotic exposure.