Stages of activation of hepatic stellate cells: effects of ellagic acid, an inhibiter of liver fibrosis, on their differentiation in culture

Therapeutic potential of berries in age-related neurological disorders

Aging significantly impacts several age-related neurological problems, such as stroke, brain tumors, oxidative stress, neurodegenerative diseases (Alzheimer's, Parkinson's, and dementia), neuroinflammation, and neurotoxicity. Current treatments for these conditions often come with side effects like hallucinations, dyskinesia, nausea, diarrhea, and gastrointestinal distress. Given the widespread availability and cultural acceptance of natural remedies, research is exploring the potential effectiveness of plants in common medicines. The ancient medical system used many botanical drugs and medicinal plants to treat a wide range of diseases, including age-related neurological problems. According to current clinical investigations, berries improve motor and cognitive functions and protect against age-related neurodegenerative diseases. Additionally, berries may influence signaling pathways critical to neurotransmission, cell survival, inflammation regulation, and neuroplasticity. The abundance of phytochemicals in berries is believed to contribute to these potentially neuroprotective effects. This review aimed to explore the potential benefits of berries as a source of natural neuroprotective agents for age-related neurological disorders.

Unlocking the Therapeutic Potential of Ellagic Acid for Non-Alcoholic Fatty Liver Disease and Non-Alcoholic Steatohepatitis

Obesity is in epidemic proportions in many parts of the world, contributing to increasing rates of non-alcoholic fatty liver disease (NAFLD). NAFLD represents a range of conditions from the initial stage of fatty liver to non-alcoholic steatohepatitis (NASH), which can progress to severe fibrosis, through to hepatocellular carcinoma. There currently exists no treatment for the long-term management of NAFLD/NASH, however, dietary interventions have been investigated for the treatment of NASH, including several polyphenolic compounds. Ellagic acid is one such polyphenolic compound. Nutraceutical food abundant in ellagic acid undergoes initial hydrolysis to free ellagic acid within the stomach and small intestine. The proposed mechanism of action of ellagic acid extends beyond its initial therapeutic potential, as it is further broken down by the gut microbiome into urolithin. Both ellagic acid and urolithin have been found to alleviate oxidative stress, inflammation, and fibrosis, which are associated with NAFLD/NASH. While progress has been made in understanding the pharmacological and biological activity of ellagic acid and its involvement in NAFLD/NASH, it has yet to be fully elucidated. Thus, the aim of this review is to summarise the currently available literature elucidating the therapeutic potential of ellagic acid and its microbial-derived metabolite urolithin in NAFLD/NASH.

Diethyldithiocarbamate inhibits the activation of hepatic stellate cells via PPARα/FABP1 in mice with non-alcoholic steatohepatitis

Activation of hepatic stellate cells (HSCs) is the main course of liver fibrosis which is positively correlated with adverse clinical outcomes in non-alcoholic steatohepatitis (NASH). Diethyldithiocarbamate (DDC) attenuates NASH related liver fibrosis in mice, but its underlying mechanisms remains unclear. In this study, the data showed that DDC inhibited the activation of HSCs in high fat choline-deficient, L-amino acid-defined (CDAA) diet induced NASH. Double Immunofluorescence analysis showed that the baseline expression of peroxisome proliferator-activated receptor α (PPARα) is high in HSCs in normal mouse liver and notably decreases in the NASH liver, indicating that PPARα might be associated with the activation of HSCs. While, DDC upregulated PPARα in HSCs in the NASH liver. Mixture of free fatty acid was used to induce steatosis of hepatocytes. Human HSCs (LX-2 cells) were activated after co-cultured with steatotic hepatocytes, and DDC inhibited the activation of LX-2 cells. Meanwhile, DDC upregulated PPARα and FABP1, and promoted the accumulation of LDs in LX-2 cells. PPARα small interfering RNA blocked these effect of DDC. These findings suggest that PPARα is associated with the activation of HSCs in the context of NASH. DDC improves NASH related fibrosis through inhibiting the activation of HSCs via PPARα/FABP1.

Ferroportin-dependent ferroptosis induced by ellagic acid retards liver fibrosis by impairing the SNARE complexes formation

Chronic liver injury causing liver fibrosis is a major cause of morbidity and mortality worldwide. Targeting the suppression of hepatic stellate cell (HSC) activation is recognized as an effective strategy for the treatment of liver fibrosis. Ellagic acid (EA), a natural polyphenol product isolated from fruits and vegetables, possesses many biological functions. Here, EA exerts its antifibrotic activity by inducing ferroptotic cell death of activated HSCs, which is accompanied by redox-active iron accumulation, lipid peroxidation, and GSH depletion in CCl₄ mice and human LX-2 cells. The specific ferroptosis inhibitor ferrostatin-1 prevented EA-induced ferroptotic cell death. Mechanistically, EA impairs the formation of vesicle-associated membrane protein 2 (VAMP2)/syntaxin 4 and VAMP2/synaptosome-associated protein 23 complexes by suppressing VAMP2 expression by enhancing its degradation in a proteasome-dependent pathway. This leads to the impairment of ferroportin (FPN, an iron exporter) translocation and intracellular iron extrusion. Interestingly, VAMP2 overexpression inhibits the role of EA in blocking FPN translocation and increasing intracellular ferritin content (an iron storage marker). In contrast, VAMP2 knockdown shows a synergistic effect on EA-mediated ferroptotic events in both HSCs. Additionally, HSC-specific overexpression of VAMP2 impaired EA-induced HSC ferroptosis in mouse liver fibrosis, and HSC-specific VAMP2 knockdown increased the inhibitory effect of EA on fibrosis. Taken together, our data suggest that the natural product EA exerts its antifibrotic effects by inducing FPN-dependent ferroptosis of HSCs by disrupting the formation of SNARE complexes, and EA will hopefully serve as a prospective compound for liver fibrosis treatment.

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EA exerts its antifibrotic activity by inducing ferroptotic cell death of activated HSCs in CCl4/BDL mice.

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EA blocks the SNARE complexes formation by suppressing VAMP2by enhancing its degradation in a proteasome-dependent pathway.

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Impairment SNARE complexes suppress FPN translocation, which in turn prevents intracellular iron extrusion.

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EA induces ferroptosis of HSCs resulting from intracellular excessive iron accumulation.

Blunting p38 MAPKα and ERK1/2 activities by empagliflozin enhances the antifibrotic effect of metformin and augments its AMPK-induced NF-κB inactivation in mice intoxicated with carbon tetrachloride

AIM

Metformin and empagliflozin combined therapy may have complementary effects that go beyond the well-recognized targets of their monotherapy through AMPK activation. Therefore, the current study was designed to investigate for the first time the hepatoprotective effects of such combination therapy in the carbon tetrachloride (CCl₄)-induced hepatic fibrosis model in mice.

MATERIALS AND METHODS

Determination of liver enzymes and the liver content of oxidative stress parameters, and hydroxyproline were performed biochemically. ELISA was performed to measure PDGF-BB, TNF-α, TGF-β, TIMP-1, AMPK, p-mTOR, NF-κB P65 binding activity, p38 MAPKα, JNK1/2 and ERK1/2. Real-time qPCR was conducted to determine Col1a1 and α-SMA. In addition, histopathological examination using H&E and Masson's trichrome stain were performed for determination of histopathological changes.

KEY FINDINGS

Empagliflozin inhibited the activation of p38 MAPK and ERK1/2 and exhibited a weak AMPKα stimulation. On the other hand, metformin exerted a more robust stimulatory action on the AMPKα that was accompanied by a notable decrease in the NF-κB nuclear binding activity and a decline in the p-mTOR levels. Nevertheless, the effect of metformin on MAPK kinases was insignificant. Our results revealed that blunting p38 MAPKα and ERK1/2 activities by empagliflozin enhanced the antifibrotic effect of metformin and augmented its AMPK-induced NF-κB inactivation.

SIGNIFICANCE

As diabetes is one of the most common risk factors for liver fibrosis, the use of antidiabetic drugs is expected to improve therapeutic outcome. Therefore, metformin/empagliflozin combined therapy could be promising in preventing hepatic inflammation and fibrosis via exhibiting complementary effects particularly in diabetic patients.

Inhibition of Hepatic Stellate Cell Activation Suppresses Tumorigenicity of Hepatocellular Carcinoma in Mice

Transdifferentiation (or activation) of hepatic stellate cells (HSCs) to myofibroblasts is a key event in liver fibrosis. Activated HSCs in the tumor microenvironment reportedly promote tumor progression. This study analyzed the effect of an inhibitor of HSC activation, retinol-binding protein–albumin domain III fusion protein (R-III), on protumorigenic functions of HSCs. Although conditioned medium collected from activated HSCs enhanced the migration, invasion, and proliferation of the hepatocellular carcinoma cell line Hepa-1c1c7, this effect was not observed in Hepa-1c1c7 cells treated with conditioned medium from R-III–exposed HSCs. In a subcutaneous tumor model, larger tumors with increased vascular density were formed in mice transplanted with Hepa-1c1c7+HSC than in mice transplanted with Hepa-1c1c7 cells alone. Intriguingly, when Hepa-1c1c7+HSC–transplanted mice were injected intravenously with R-III, a reduction in vascular density and extended tumor necrosis were observed. In an orthotopic tumor model, co-transplantation of HSCs enhanced tumor growth, angiogenesis, and regional metastasis accompanied by increased peritumoral lymphatic vessel density, which was abolished by R-III. In vitro study showed that R-III treatment affected the synthesis of pro-angiogenic and anti-angiogenic factors in activated HSCs, which might be the potential mechanism underlying the R-III effect. These findings suggest that the inhibition of HSC activation abrogates HSC-induced tumor angiogenesis and growth, which represents an attractive therapeutic strategy.

Ellagic Acid Attenuates BLM-Induced Pulmonary Fibrosis via Inhibiting Wnt Signaling Pathway

Idiopathic pulmonary fibrosis is a progressive lung disease with high mortality and limited therapy that is characterized by epithelial cell damage and fibroblast activation. Ellagic acid is a natural polyphenol compound widely found in fruits and nuts that has multiple pharmacological activities. In this study, we explored the potential effects and mechanisms of Ellagic acid on pulmonary fibrosis in vivo and in vitro. In vivo studies showed that Ellagic acid significantly alleviated bleomycin (BLM)-induced pulmonary fibrosis in mice. In vitro experiments indicated that Ellagic acid could suppress Wnt signaling and attenuate Wnt3a-induced myofibroblast activation and the phosphorylation of Erk2 and Akt. Further studies showed that Ellagic acid could induce autophagy formation in myofibroblasts mainly by suppressing mTOR signaling and promoting apoptosis of myofibroblasts. In vivo experiments revealed that Ellagic acid significantly inhibited myofibroblast activation and promoted autophagy formation. Taken together, our results show that Ellagic acid effectively attenuates BLM-induced pulmonary fibrosis in mice by suppressing myofibroblast activation and promoting autophagy and apoptosis of myofibroblasts by inhibiting the Wnt signaling pathway.

Role of ellagic acid for the prevention and treatment of liver diseases

Globally, one of the alarming problems is the prevalence and burden of liver diseases, which accounts for 2 million cases per year. Chronic liver aetiologies such as hepatitis infections, alcoholic or non-alcoholic liver disease, environmental agents, and drug-induced toxicity are invariably responsible for liver fibrosis progression to finally hepatocellular carcinoma. Current treatment options are unable to overwhelm and cure liver diseases. Emerging findings suggest researchers' interest in using evidence-based complementary medicine such as ellagic acid with extensive pharmacological properties. They include antioxidant, anti-inflammatory, anti-hyperlipidaemic, anti-viral, anti-angiogenic, and anticancer activity. The molecular functions elicited by ellagic acid include scavenging of free radicals, regulation of lipid metabolism, the prohibition of fibrogenesis response-mediating proteins, inhibits hepatic stellate cells and myofibroblasts, restrains hepatic viral replication, facilitates suppression of growth factors, regulates transcription factors, proinflammatory cytokines, augments the liver immune response, fosters apoptosis and inhibits cell proliferation in tumorigenic cells. This review will most notably focus on preclinical and clinical information based on currently available evidence to warrant ellagic acid's prospective role in preventing liver diseases.

Ellagic Acid Activated PPAR Signaling Pathway to Protect Ileums Against Castor Oil-Induced Diarrhea in Mice: Application of Transcriptome Analysis in Drug Screening

Background

Acute diarrhea is still a common and serious disease. The causes of acute diarrhea are very complicated. Therefore, we need to find a medicine to control diarrhea symptoms, save time for diagnosis of pathogens, and prevent drug abuse. Ellagic acid (EA), a natural polyphenol drug, has anti-diarrhea effects. However, the action mechanisms of EA for non-specific diarrhea have not been characterized.

Materials and Methods

To study the mechanisms of EA, mice were divided into four groups. Group C were intraperitoneally injected with 0.1 ml physiological saline and orally given 0.2 ml physiological saline, and then after experiment began 0.5 h, orally administered 0.3 ml physiological saline. Group D were intraperitoneally injected with 0.1 ml physiological saline and orally given 0.2 ml castor oil, and then after experiment began 0.5 h, orally administered 0.3 ml physiological saline. Group E were intraperitoneally injected with 0.1 ml physiological saline and orally given 0.2 ml castor oil, and then after experiment began 0.5 h, orally administered 0.3 ml EA (10 mg/ml). Group V were intraperitoneally injected with 0.1ml GW9662 (1m g/ml) and orally given 0.2 ml castor oil, and then after experiment began 0.5 h, orally administered 0.3 ml EA (10 mg/ml). Transcriptome were performed on ileum tissues of mice in group D and E. Histological examination and qRT-PCR were performed on ileum tissues of mice in group C, D, E, and V.

Results

We found that a total of 273 differentially expressed genes (DEGs) were obtained, including 160 up-regulated DEGs and 113 down-regulated DEGs. The DEGs were enriched in 458 Gene Ontology (GO) terms and 15 Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways, respectively. The peroxisome proliferator activated receptor (PPAR) signaling pathway was the most significantly enriched in KEGG pathways. We used the PPAR-specific antagonist GW9662 to validate the anti-diarrhea and anti-inflammatory effect of EA in group V compared with group E. Conclusively, EA protected ileums against castor oil-induced inflammation and diarrhea by activating the PPAR signaling pathway and a method was used to study the mechanism of EA.

Hepatoprotective influence of quercetin and ellagic acid on thioacetamide-induced hepatotoxicity in rats

Despite all the studies performed to date, therapy choices for liver injuries are very few. Therefore, the search for a new treatment that could safely and effectively block or reverse liver injuries remains a challenge. Quercetin (QR) and ellagic acid (EA) had potent antioxidant and anti-inflammatory activities. The current study aimed at evaluating the potential hepatoprotective influence of QR and EA against thioacetamide (TAA)-induced liver toxicity in rats and the underlying mechanism using silymarin as a reference drug. Fifty mature male rats were orally treated daily with EA and QR in separate groups for 45 consecutive days, and then were injected with TAA twice with 24 h intervals in the last 2 days of the experiment. Administration of TAA resulted in marked elevation of liver indices, alteration in oxidative stress parameters, and significant elevation in expression level of fibrosis-related genes (MMP9 and MMP2). Administration of QR and EA significantly attenuated the hepatic toxicity through reduction of liver biomarkers, improving the redox status of the tissue, as well as hampering the expression level of fibrosis-related genes. In this study, QR and EA were proved to attenuate the hepatotoxicity through their antioxidant, metal-chelating capacity, and anti-inflammatory effects.

Schistosome-Induced Fibrotic Disease: The Role of Hepatic Stellate Cells

Hepatic fibrosis is a common pathology in various liver diseases. Hepatic stellate cells (HSCs) are the main cell type responsible for collagen deposition and fibrosis formation in the liver. Schistosomiasis is characterised by granulomatous fibrosis around parasite eggs trapped within the liver and other host tissues. This response is facilitated by the recruitment of immune cells and the activation of HSCs. The interactions between HSCs and schistosome eggs are complex and diverse, and a better understanding of these interactions could lead to improved resolution of fibrotic liver disease, including that associated with schistosomiasis. Here, we discuss recent advances in HSC biology and the role of HSCs in hepatic schistosomiasis.

Ellagic acid inhibits the proliferation of human pancreatic carcinoma PANC-1 cells in vitro and in vivo

Ellagic aicd (EA), a dietary polyphenolic compound found in plants and fruits, possesses various pharmacological activities. This study investigated the effect of EA on human pancreatic carcinoma PANC-1 cells both in vitro and in vivo; and defined the associated molecular mechanisms. In vitro, the cell growth and repairing ability were assessed by CCK-8 assay and wound healing assay. The cell migration and invasion activity was evaluated by Tanswell assay. In vivo, PANC-1 cell tumor-bearing mice were treated with different concentrations of EA. We found that EA significantly inhibited cell growth, cell repairing activity, and cell migration and invasion in a dose-dependent manner. Treatment of PANC-1 xenografted mice with EA resulted in significant inhibition in tumor growth and prolong mice survival rate. Furthermore, flow cytometric analysis showed that EA increased the percentage of cells in the G1 phase of cell cycle. Western blot analysis revealed that EA inhibited the expression of COX-2 and NF-κB. In addition, EA reversed epithelial to mesenchymal transition by up-regulating E-cadherin and down-regulating Vimentin. In summary, the present study demonstrated that EA inhibited cell growth, cell repairing activity, cell migration and invasion in a dose-dependent manner. EA also effectively inhibit human pancreatic cancer growth in mice. The anti-tumor effect of EA might be related to cell cycle arrest, down-regulating the expression of COX-2 and NF-κB, reversing epithelial to mesenchymal transition by up-regulating E-cadherin and down-regulating Vimentin. Our findings suggest that the use of EA would be beneficial for the management of pancreatic cancer.

Ellagic acid inhibits iron-mediated free radical formation

Polyphenols are reported to have some health benefits, which are link to their antioxidant properties. In the case of ellagic acid (EA), there is evidence that it has free radical scavenger properties and that it is able to form complexes with metal ions. However, information on a possible link between the formation of iron-EA complexes and their interference in Haber-Weiss/Fenton reactions was not yet determined. Thus, the present study investigated the in vitro antioxidant mechanism of EA in a system containing ascorbate, Fe(III) and different iron ligands (EDTA, citrate and NTA). Iron-mediated oxidative degradation of 2-deoxyribose was poorly inhibited (by 12%) in the presence of EA (50μM) and EDTA. When citrate or NTA - which form weak iron complexes - were used, the 2-deoxyribose protection increased to 89-97% and 45%, respectively. EA also presented equivalent inhibitory effects on iron-mediated oxygen uptake and ascorbyl radical formation. Spectral analyses of iron-EA complexes show that EA removes Fe(III) from EDTA within hours, and from citrate within 1min. This difference in the rate of iron-EA complex formation may explain the antioxidant effects of EA. Furthermore, the EA antioxidant effectiveness was inversely proportional to the Fe(III) concentration, suggesting a competition with EDTA. In conclusion, the results indicate that EA may prevent in vitro free radical formation when it forms a complex with iron ions.

Beneficial effects of ellagic acid against animal models of scopolamine- and diazepam-induced cognitive impairments

Context In a previous study, it has been shown that ellagic acid (EA), a polyphenolic compound found in pomegranate and different berries, prevents cognitive and hippocampal long-term potentiation (LTP) impairments induced by traumatic brain injury in rats through antioxidant and anti-inflammatory mechanisms. Objective The present study was conducted to assess the potential of EA as a memory enhancer. Materials and methods The elevated plus maze (EPM) and passive avoidance (PA) paradigm were used to evaluate learning and memory parameters. Three doses (10, 30 and 100 mg/kg, i.p.) of EA were administered to animals. Memory impairment was induced by scopolamine treatment (0.4 mg/kg, i.p.) and/or diazepam (1 mg/kg, i.p.). Acquisition trials were carried out 30 min after scopolamine treatment and retention trials were performed for 5 min 24 h after the acquisition trials. Results EA at doses 30 and 100 mg/kg significantly reversed the amnesia induced by scopolamine (0.4 mg/kg, i.p.) in the EPM and PA tests in mice. Also, EA at doses 30 and 100 mg/kg significantly antagonized the amnesia induced by diazepam (1 mg/kg, i.p.) in EPM test in rats. Moreover, chronic administration of EA at dose 30 mg/kg ameliorated the memory deficit induced by diazepam (1 mg/kg, i.p.) in rats. Discussion and conclusion This study demonstrates that ellagic acid is effective in preventing scopolamine- and diazepam-induced cognitive impairments without altering the animals' locomotion. This suggests the potential of EA application as a useful memory restorative agent in the treatment of dementia seen in elderly persons.

Protective effects of ellagic acid and ozone on rat ovaries with an ischemia/reperfusion injury

AIM

This study investigated the effects of the antioxidant agents, ozone (O) and ellagic acid (EA), on ischemia/reperfusion (I/R) injuries developed from an ovarian torsion-detorsion model.

MATERIALS AND METHODS

Arteries in the left ovaries of rats were clamped for two hours to achieve torsion, and then the clamps were removed for a two-hour detorsion period. Thirty-five female Sprague-Dawley rats were randomly divided into five groups: control: administered only with anesthesia, rats were not subjected to torsion-detorsion; I/R: subjected to torsion and subsequent detorsion, without administering any treatment agent; and I/R + EA, I/R + O and I/R + O + EA: subjected to torsion and detorsion processes and administered with EA, O or EA + O at the 75th minute of torsion. The rats were then sacrificed under general anesthesia and the ovarian tissues were excised. The tissues were homogenized and levels of glutathione reductase, catalase, superoxide dismutase and malondialdehyde (MDA) were analyzed. Tissue damage was evaluated in terms of histopathological parameters, such as hemorrhage, congestion, edema and inflammation.

RESULTS

Antioxidant enzyme activity and MDA levels in the ovary tissue increased in the I/R group and decreased in the O, EA and O + EA groups (P < 0.05). Histopathological examination revealed that tissue damage in the O, EA and O + EA groups decreased in comparison with the I/R group (P < 0.05).

CONCLUSIONS

These biochemical and histopathological findings suggest that EA and O are effective against ovarian I/R injury.

Sildenafil enhances the peripheral antinociceptive effect of ellagic acid in the rat formalin test

Objective:

Ellagic acid (EA), a major polyphenolic compound of pomegranate juice, produces antinociceptive effects, which are mediated through opioidergic and nitric oxide-cyclic guanosine monophosphate (NO-cGMP) pathways. The present study was conducted to elucidate the peripheral antinociceptive effect of EA alone and in combination with sildenafil in the rat formalin test.

Materials and Methods:

Pain was produced by intraplantar injection of formalin (2.5%) in rats and nociceptive behavior was measured as the number of flinches every 5 min in 60 min after injection.

Results:

Local administration of EA and sildenafil dose-dependently increased the nociception threshold in both phases of the test. Moreover, sub-effective doses of sildenafil (25 or 50 mcg/paw, i.p.) significantly and dose-dependently enhanced the antinociception induced by a sub-effective dose of EA (60 mcg/paw, i.pl.) in both phases of the test. The antinociception produced by these drugs alone, or in combination, was due to a peripheral site of action, since the administration in the contralateral paw was ineffective.

Conclusion:

Our results suggest that EA has local peripheral antinociceptive activity, and enhancement of this effect with sildenafil probably occurs through the inhibition of cGMP metabolism.

Involvement of L-arginine/NO/cGMP/K(ATP) channel pathway in the peripheral antinociceptive actions of ellagic acid in the rat formalin test

The present study was conducted to evaluate the local antinociceptive actions of EA and the possible involvement of l-arginine/NO/cGMP/KATP channel pathway in this effect using formalin test in rats. To evaluate the involvement of l-arginine/NO/cGMP/KATP channel pathway in the antinociceptive action of EA, rats were pre-treated intraplantarlly with l-NAME (NOS inhibitor, 25-100μg/paw), methylene blue (guanylyl cyclase inhibitor, 100-400μg/paw), glibenclamide (ATP-sensitive K(+) channel blocker, 25-100μg/paw), l-arginine (a nitric oxide precursor, 25-100μg/paw) and sodium nitroprusside (125-500μg/paw). The local peripheral ipsilateral, but not contralateral, administration of EA into the right paw (30-300μg/paw) produced a dose-related antinociception during both early and late phases of formalin test which is comparable with morphine (25μg/paw). Moreover, local pre-treatment with l-NAME, methylene blue and glibenclamide dose-dependently prevented EA (100μg/paw)-induced antinociception in late phase. Additionally, administration of l-arginine and sodium nitroprusside significantly potentiated the antinociception induced by EA in the late phase. However, these treatments had no significant effect on antinociceptive response of EA in the early phase of the formalin test. The results of the present study showed that EA-induced local peripheral antinociception during the both phases of formalin test. Also, our data suggested the activation of the l-arginine/NO/cGMP/KATP channels pathway in EA-induced antinociception in late phase of formalin test. Topical application of EA by ointment or jelly might be a useful method to relieving the inflammatory pain states.

The protective role of ellagitannins flavonoids pretreatment against N-nitrosodiethylamine induced-hepatocellular carcinoma

Ellagitannins are esters of glucose with hexahydroxydiphenic acid; when hydrolyzed, they yield ellagic acid (EA), the dilactone of hexahydroxydiphenic acid. EA has been receiving the most attention, because it has potent antioxidant activity, radical scavenging capacity, chemopreventive and antiapoptotic properties. Hepatocellular carcinoma (HCC) is the most frequent primary malignancy of liver, and accounts for as many as one million deaths worldwide in a year. The aim of the present study was to evaluate the antioxidant and chemopreventive efficiency of ellagic acid against N-nitrosodiethylamine (NDEA) induced hepatocarcinogenesis in rats. Rats were classified into four groups as follows: normal control group, group injected i.p. with a single dose (200 mg/kg b.wt.) of NDEA, third group daily administered orally EA with a dose of 50 mg/kg b.wt. for 7 days before and 14 days after NDEA administration, and fourth group received a similar dose of EA for 21 days after the dose of NDEA administration. The model of NDEA-injected hepatocellular carcinomic (HCC) rats elicited significant declines in liver antioxidant enzyme activities; glutathione peroxidase (GPX), gamma glutamyl transferase (γ-GT) and glutathione-S-transferase (GST), with a reduction in reduced glutathione (GSH) and serum total protein with concomitant significant elevations in tumor markers arginase and α-l-fucosidase, and liver enzymes; aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), and glutathione-S-transferase (GST), glucose-6-phosphate dehydrogenase (G6PD), direct and total bilirubin. The oral administration of EA as a protective agent, produced significant increases in tested antioxidant enzyme activities and serum total protein concomitant with significant decreases in the levels of tumor markers arginase and α-l-fucosidase as well as liver enzymes, direct and total bilirubin. Similarly, the oral administration of EA, as a curative agent produced similar changes to those when EA was used as a protective agent, but to a lesser extent. In addition, it was noted that HCC rats exhibited a degree of DNA fragmentation; however, EA administration partially inhibited the DNA fragmentation. Therefore, EA has the ability to scavenge free radicals, prevent DNA fragmentation, reduce liver injury and protect against oxidative stress.

Recent advances in natural products from plants for treatment of liver diseases

Liver disease is any condition that may cause liver inflammation or tissue damage and affects liver function. Natural products that are found in vegetables, fruits, plant extracts, herbs, insects, and animals, have been traditionally used for treating liver diseases. They are chemical compounds that usually have biological activities for use in drug discovery and design. Many natural products have been clinically available as potent hepatoprotective agents against commonly occurring liver diseases. This review summarizes the current progress in the basic, clinical, and translational research on natural products in treatment of various liver diseases. Furthermore, we will focus on the discovery and biological evaluation of the natural products, which shows potential as a new therapeutic agent of liver diseases.

Hepatoprotective activities of picroliv, curcumin, and ellagic acid compared to silymarin on carbon-tetrachloride-induced liver toxicity in mice

Introduction:

To evaluate the hepatoprotective activity of active phytochemicals, picroliv, curcumin, and ellagic acid in comparison to silymarin in the mice model of carbon tetrachloride (CCl₄) induced liver toxicity. In addition, attempts were made to elucidate their possible mechanism(s) of action.

Materials and Methods:

Oxidative stress was induced in Swiss albino mice by a single injection (s.c.) of CCl₄, 1 ml/kg body weight, diluted with arachis oil at a 1:1 ratio. The phytochemicals were administered once a day for 7& days (p.o.) as pretreatment at two dose levels (50 and 100 mg/kg/day).

Results:

CCl₄-induced hepatotoxicity was manifested by an increase in the activities of liver enzymes (alanine transaminase, P < 0.001, aspartate transaminase, P < 0.001 and alkaline phosphatase, P < 0.001), malondialdehyde (MDA, P < 0.001)) levels and a decrease in activity of reduced glutathione (P < 0.001) and catalase in liver tissues. The histopathological examination of liver sections revealed centrizonal necrosis, fatty changes, and inflammatory reactions. The pretreatment with picroliv, curcumin, and ellagic acid normalized serum aminotransferase activities (P < 0.001), decreased levels of MDA (P < 0.001), improved the antioxidant status, and normalized the hepatic histo-architecture. The restoration of phenobarbitone-induced sleeping time also suggested the normalization of liver cytochrome P450 enzymes.

Conclusion:

This study supports the use of these active phytochemicals against toxic liver injury, which may act by preventing lipid peroxidation, augmenting the antioxidant defense system or by regenerating the hepatocytes.

Zinc-chelation contributes to the anti-angiogenic effect of ellagic acid on inhibiting MMP-2 activity, cell migration and tube formation

Background

Ellagic acid (EA), a dietary polyphenolic compound, has been demonstrated to exert anti-angiogenic effect but the detailed mechanism is not yet fully understood. The aim of this study was to investigate whether the zinc chelating activity of EA contributed to its anti-angiogenic effect.

Methods and Principal Findings

The matrix metalloproteinases-2 (MMP-2) activity, a zinc-required reaction, was directly inhibited by EA as examined by gelatin zymography, which was reversed dose-dependently by adding zinc chloride. In addition, EA was demonstrated to inhibit the secretion of MMP-2 from human umbilical vein endothelial cells (HUVECs) as analyzed by Western blot method, which was also reversed by the addition of zinc chloride. Reversion-inducing cysteine-rich protein with Kazal motifs (RECK), known to down-regulate the MMP-2 activity, was induced by EA at both the mRNA and protein levels which was correlated well with the inhibition of MMP-2 activity. Interestingly, zinc chloride could also abolish the increase of EA-induced RECK expression. The anti-angiogenic effect of EA was further confirmed to inhibit matrix-induced tube formation of endothelial cells. The migration of endothelial cells as analyzed by transwell filter assay was suppressed markedly by EA dose-dependently as well. Zinc chloride could reverse these two effects of EA also in a dose-dependent manner. Since magnesium chloride or calcium chloride could not reverse the inhibitory effect of EA, zinc was found to be involved in tube formation and migration of vascular endothelial cells.

Conclusions/Significance

Together these results demonstrated that the zinc chelation of EA is involved in its anti-angiogenic effects by inhibiting MMP-2 activity, tube formation and cell migration of vascular endothelial cells. The role of zinc was confirmed to be important in the process of angiogenesis.

Response of sinusoidal mouse liver cells to choline-deficient ethionine-supplemented diet

BACKGROUND

Proliferation of oval cells, the bipotent precursor cells of the liver, requires impeded proliferation and loss of hepatocytes as well as a specific micro-environment, provided by adjacent sinusoidal cells of liver. Despite their immense importance for triggering the oval cell response, cells of hepatic sinusoids are rarely investigated. To elucidate the response of sinusoidal liver cells we have employed a choline-deficient, ethionine-supplemented (CDE) diet, a common method for inducing an oval cell response in rodent liver. We have utilised selected expression markers commonly used in the past for phenotypic discrimination of oval cells and sinusoidal cells: cytokeratin, E-cadherin and M2-pyruvate kinase for oval cells; and glial fibrillary acidic protein (GFAP) was used for hepatic stellate cells (HSCs).

RESULTS

CDE diet leads to an activation of all cells of the hepatic sinusoid in the mouse liver. Beside oval cells, also HSCs and Kupffer cells proliferate. The entire fraction of proliferating cells in mouse liver as well as endothelial cells and cholangiocytes express M2-pyruvate kinase. Concomitantly, GFAP, long considered a unique marker of quiescent HSCs was upregulated in activated HSCs and expressed also in cholangiocytes and oval cells.

CONCLUSIONS

Our results point to an important role of all types of sinusoidal cells in regeneration from CDE induced liver damage and call for utmost caution in using traditional marker for identifying specific cell types. Thus, M2-pyruvate kinase should no longer be used for estimating the oval cell response in mouse liver. CDE diet leads to activation of GFAP positive HSCs in the pericentral zone of liver lobulus. In the periportal zone the detection of GFAP in biliary cells and oval cells, calls other cell types as progenitors of hepatocytes into question under CDE diet conditions.

Antifibrotic activity of Taraxacum officinale root in carbon tetrachloride-induced liver damage in mice

AIM OF THE STUDY

Dandelion (Taraxacum officinale) has been traditionally used in the treatment of various liver disorders. The present study was aimed to assess the efficacy of dandelion root water-ethanol extract (DWE) in carbon tetrachloride (CCl(4))-induced hepatic fibrosis.

MATERIALS AND METHODS

The mice were treated with CCl(4) dissolved in olive oil (20%, v/v, 2 ml/kg) intraperitoneally (i.p.), twice a week for 4 weeks. DWE was administered i.p. once daily for next 10 days, in doses of 200 and 600 mg/kg of body weight. The degree of hepatic fibrosis was determined by hydroxyproline content and Mallory trichrome staining. Oxidative stress was determined by measuring hepatic superoxide dismutase (Cu/Zn SOD) activity. The expression and specific tissue distribution of glial fibrillary acidic protein (GFAP), alpha-smooth muscle actin (alpha-SMA), and metallothionein (MT) I/II in the liver were determined by immunohistochemistry.

RESULTS

Hepatic Cu/Zn SOD activity has been decreased in intoxicated mice and normalized in DWE treated groups. MT I/II immunopositivity was strongly reduced in the CCl(4) group. DWE treatment successfully decreased hepatic fibrinous deposits, restored histological architecture, and modulate the expression of GFAP and alpha-SMA. Concomitantly, MT I/II expression increased in the DWE treated groups.

CONCLUSIONS

Our results suggest the therapeutic effect of DWE on CCl(4)-induced liver fibrosis by the inactivation of hepatic stellate cells and the enhancement of hepatic regenerative capabilities. The present results provide scientific evidence to substantiate the traditional use of Taraxacum officinale root in hepatic disorders.

Up-regulation of uPARAP/Endo180 during culture activation of rat hepatic stellate cells and its presence in hepatic stellate cell lines from different species

Background

The urokinase plasminogen activator receptor associated protein (uPARAP)/Endo180 is a novel endocytic receptor that mediates collagen uptake and is implicated to play a role in physiological and pathological tissue-remodelling processes by mediating intracellular collagen degradation.

Result

This study investigates the expression of uPARAP/Endo180 protein and messenger RNA in primary rat hepatic stellate cell (HSC) cultures. The results show that uPARAP/Endo180 protein is not expressed in freshly isolated HSCs or during the first few days of culture while the cells still display quiescent features. In contrast, uPARAP/Endo180 protein is expressed early during HSC activation when cells are transdifferentiated into myofibroblast-like cells. Very low levels of uPARAP/Endo180 mRNA are detectable during the first days of culture but uPARAP/Endo180 mRNA is strongly up-regulated with increasing time in culture. Moreover, endocytic uptake of denatured collagen increases as transdifferentiation proceeds over time and correlates with increased expression of uPARAP/Endo180. Finally, analysis of uPARAP/Endo180 expression in four hepatic stellate cell lines from three different species showed that all these cell lines express uPARAP/Endo180 and are able to take up denatured collagen efficiently.

Conclusion

These results demonstrate that uPARAP/Endo180 expression by rat HSCs is strongly up-regulated during culture activation and identify this receptor as a feature common to culture-activated HSCs.

Drug development for liver diseases: focus on picroliv, ellagic acid and curcumin

The use of herbal drugs for the treatment of liver diseases has a long tradition in many eastern countries. The easy accessibility without the need for laborious pharmaceutical synthesis has drawn increased attention towards herbal medicines. Few herbal preparations exist as standardized extracts with major known ingredients or even as pure compounds. Some of the herbals, which show promising activity, are ellagic acid for antifibrotic treatment, phyllanthin for treating chronic hepatitis B, glycyrrhizin to treat chronic viral hepatitis and picroliv for liver regeneration. These compounds, which have proven antioxidant, antiviral or anticarcinogenic properties, can serve as primary compounds for further development as hepatoprotective drugs. This review provides the chemistry, pharmacology and future aspects of picroliv, ellagic acid and curcumin with focus on hepatoprotective properties. These phytochemicals may prove to be very useful in the treatment of hepatotoxicity induced by viral agents, toxic drugs and plant poisons. The high safety profile may be an added advantage. However, poor bioavailability and temperature and light sensitivity can reduce the efficacy of drugs like curcumin. In future, the derivatives or new combinations of these drugs may prove to be useful.

Keratinocytes as depository of ammonium-inducible glutamine synthetase: age- and anatomy-dependent distribution in human and rat skin

In inner organs, glutamine contributes to proliferation, detoxification and establishment of a mechanical barrier, i.e., functions essential for skin, as well. However, the age-dependent and regional peculiarities of distribution of glutamine synthetase (GS), an enzyme responsible for generation of glutamine, and factors regulating its enzymatic activity in mammalian skin remain undisclosed. To explore this, GS localization was investigated using immunohistochemistry and double-labeling of young and adult human and rat skin sections as well as skin cells in culture. In human and rat skin GS was almost completely co-localized with astrocyte-specific proteins (e.g. GFAP). While GS staining was pronounced in all layers of the epidermis of young human skin, staining was reduced and more differentiated among different layers with age. In stratum basale and in stratum spinosum GS was co-localized with the adherens junction component beta-catenin. Inhibition of, glycogen synthase kinase 3beta in cultured keratinocytes and HaCaT cells, however, did not support a direct role of beta-catenin in regulation of GS. Enzymatic and reverse transcriptase polymerase chain reaction studies revealed an unusual mode of regulation of this enzyme in keratinocytes, i.e., GS activity, but not expression, was enhanced about 8-10 fold when the cells were exposed to ammonium ions. Prominent posttranscriptional up-regulation of GS activity in keratinocytes by ammonium ions in conjunction with widespread distribution of GS immunoreactivity throughout the epidermis allows considering the skin as a large reservoir of latent GS. Such a depository of glutamine-generating enzyme seems essential for continuous renewal of epidermal permeability barrier and during pathological processes accompanied by hyperammonemia.

Activation of hepatic stellate cells is associated with cytokine expression in thioacetamide-induced hepatic fibrosis in mice

The pathophysiological mechanisms of thioacetamide (TAA)-induced hepatic fibrogenesis are not yet fully understood. In particular, the role of hepatic stellate cells (HSCs) remains unclear. We therefore examined proliferation and transdifferentiation of HSC as well as the underlying molecular mechanisms in TAA-induced fibrosis. Hepatic fibrogenesis was induced in mice by addition of TAA to drinking water. Liver damage was determined by assessment of alanine aminotransferase and aspartate aminotransferase levels, and measurement of collagen deposition. Additionally, expression patterns of alpha-smooth muscle actin, glial fibrillary acidic protein (GFAP, specific hepatic biomarker for HSC), cysteine- and glycine-rich protein 2 (CRP2, specific marker of HSC transdifferentiation), tissue inhibitor of metalloproteinases-1, matrix metalloproteinase-9 (MMP-9), interleukins (IL-1beta, IL-6), platelet-derived growth factors (PDGF-B, PDGF-D) , tumor necrosis factor (TNF)-alpha, and (transforming growth factor (TGF)-beta1 were assessed by real-time PCR. Transcription of GFAP and CRP2 were transiently upregulated during TAA-induced fibrogenesis (punctum maxima (p.m.) week 10 for GFAP and week 14 for CRP2). Similar transient expression patterns were demonstrated for IL-1beta, IL-6, TGF-beta1, and PDGF-B (p.m. week 12) whereas TNF-alpha and PDGF-D continuously increased with ongoing liver injury. In particular, not only neutrophil granulocytes, but also macrophages and leukocytes served as a major source for MMP-9 expression. GFAP and CRP2 expression patterns demonstrated transiently increased HSC-activation during TAA-induced hepatic fibrogenesis. The rate of increase of transcription of GFAP correlated best with PDGF-B, whereas CRP2 levels correlated with PDGF-B, PDGF-D, and IL-1beta expression. This study demonstrates for the first time that transiently increased activation patterns of HSC are observed in toxically induced hepatic fibrosis. Thus, TAA in drinking water is an effective and elegant model to induce reproducible states of liver fibrosis without parenchymal damage in mice.

Roles of vitamin A and macula flava in maintaining vocal folds

OBJECTIVES

Vitamin A plays important roles in development, growth, and regeneration. Vitamin A-storing stellate cells have been identified in several organs. The functional roles of vitamin A in the vocal folds are still unknown, although vitamin A-storing vocal fold stellate cells have been observed in the macula flava of human and rat vocal folds. The purpose of this study was to investigate the roles of vitamin A in vocal folds.

METHODS

Vitamin A-deficient rats were generated, and the vocal folds were examined histologically. Messenger RNA was extracted from the vocal folds and analyzed by real-time polymerase chain reaction.

RESULTS

Immunohistochemical analysis of normal vocal folds revealed expression of retinoic acid receptor a in vocal fold stellate cells. The cells in the macula flava of vitamin A-deficient rats showed a larger nucleus/cytoplasm ratio than did those of vitamin A-sufficient rats, but messenger RNA expression of major extracellular matrix components in the macula flava of vitamin A-deficient rats did not present a remarkable change except for procollagen type I. Expression of hyaluronic acid, collagen types I and III, and elastin did not show a significant change in vitamin A-deficient rat vocal folds.

CONCLUSIONS

These results indicate that vitamin A is not essential to maintaining the extracellular matrix of normal adult vocal folds, although vocal fold stellate cells participate in vitamin A storage.

The inhibition of human glutathione S-transferases activity by plant polyphenolic compounds ellagic acid and curcumin

Glutathione S-transferases (GSTs) are multifunctional detoxification proteins that protect the cell from electrophilic compounds. Overexpression of GSTs in cancer results in resistance to chemotherapeutic agents and inhibition of the over expressed GST has been suggested as an approach to combat GST-induced resistance. The inhibition of human recombinant GSTs by natural plant products was investigated in this study. Using 1-chloro-2,4 dinitrobenzene (CDNB) as a substrate, ellagic acid and curcumin were shown to inhibit GSTs A1-1, A2-2, M1-1, M2-2 and P1-1 with IC(50) values ranging from 0.04 to 5 microM whilst genistein, kaempferol and quercetin inhibited GSTs M1-1 and M2-2 only. The predominant mode of inhibition with respect to the G and H-sites were mixed inhibition and uncompetitive to a lesser extent. The K(i) (K(i)(')) values for ellagic acid and curcumin with respect to GSH and CDNB were in the range 0.04-6 microM showing the inhibitory potency of these polyphenolic compounds. Ellagic acid and curcumin also showed time- and concentration-dependent inactivation of GSTs M1-1, M2-2 and P1-1 with curcumin being a more potent inactivator than ellagic acid. These results facilitate the understanding of the interaction of human GSTs with plant polyphenolic compounds with regards to their role as chemomodulators in cases of GST-overexpression in malignancies.

Colocalization of glial fibrillary acidic protein, metallothionein, and MHC II in human, rat, NOD/SCID, and nude mouse skin keratinocytes and fibroblasts

The expression of glial fibrillary acidic protein (GFAP) by perivascular cells of many mammalian organs suggests an as yet unknown function of this intermediate filament protein in the maintenance of homeostasis and vascular permeability at the blood-tissue interface. Although a similar situation may exist at the air-tissue interface, the cellular distribution of GFAP in skin tissue has never been demonstrated. To approach this issue, we have employed immunofluorescence and Western blotting techniques to detect GFAP in skin sections of young and adult humans, normal rodents, and two types of mutant mice, as well as in rat lung sections, and in cultured human keratinocytes and fibroblasts. Colocalization with antigens known to be associated with GFAP in other tissues was also tested. Epidermal and hair follicle keratinocytes and dermal fibroblasts showed distinct staining for GFAP as well as colocalization with alpha-actin, metallothionein, and antigens of the class-II major histocompatibility complex (MHC II). GFAP was also identified in rat alveolar fibroblasts which, in common with keratinocytes, form part of the air-tissue interface. GFAP was upregulated together with MHC II in nude mice but was barely detectable in the skin of non-obese diabetic severe combined immunodeficiency mice, suggesting a possible involvement in antigen-presenting functions. The intriguing distribution of a common set of antigens both in certain cells of the integumentary system and at the blood-tissue interfaces of internal organs suggests the involvement of these proteins in universal mechanisms controlling tissue homeostasis and protection.

Relationship between oxidative stress levels and activation state on a hepatic stellate cell line

BACKGROUND/AIMS

Oxidative stress plays an important role in liver fibrosis. Under pathological conditions, hepatic stellate cells (HSC) undergo an activation process, developing a myofibroblast-like phenotype from the lipocyte phenotype. In this study, we determined the levels of oxidative stress and proliferation in different activation states of an experimental model of mouse HSC, the GRX cell line. These cells can be induced in vitro to display a more activated state or a quiescent phenotype.

METHODS/RESULTS

We observed increased oxidative damage and higher levels of reactive oxygen species, measured by thiobarbituric acid reactive species and 2',7'-dichlorofluorescein diacetate, respectively, and diminished catalase activity in activated cells. Activation decreased proliferation and increased the number of cells in G2/M. Antioxidants N-acetylcysteine and Trolox varied in their capacity to correct the oxidative stress and proliferation status.

CONCLUSIONS

The differences in physiological functions of stellate cell phenotypes suggest a relationship between oxidative stress levels and activation state.

Hepatic stellate cells in human schistosomiasis mansoni: a comparative immunohistochemical study with liver cirrhosis

This study compares the populations of liver mesenchymal cells (LMCs) and their proliferative activity in schistosomal periportal fibrosis and in hepatitis C virus-induced cirrhosis. LMCs were evaluated by immunohistochemical double staining for proliferating cell nuclear antigen (PCNA) and alpha-smooth muscle actin (alpha-SMA) or glial fibrillary acid protein (GFAP) in liver biopsies from humans with schistosomal fibrosis (n=40), hepatitis C virus-induced cirrhosis (n=20), and normal controls (n=20). The number of LMCs was found to be higher in schistosomal fibrosis than in the normal liver, but lower than in cirrhosis. alpha-SMA- and GFAP-positive cells were increased in both diseases, but more so in cirrhosis. In cirrhotic liver, alpha-SMA-positive cells were highly predominant in relation to GFAP-positive cells. However, there was an inverted ratio between these cells in schistosomiasis as compared to cirrhosis. The PCNA labeling index was higher in alpha-SMA-positive cells than in GFAP-positive cells, and did not differ between pipe-stem fibrosis and liver cirrhosis regarding alpha-SMA- or GFAP-positive cells. The predominance of GFAP-positive cells observed in schistosomiasis suggests that hepatic stellate cells (HSCs) have a major role in connective tissue deposition in the human schistosomal liver. On the other hand, the smaller number of LMCs in schistosomal fibrosis in comparison to liver cirrhosis may be related to mild and limited injury due to the schistosomal egg-induced inflammatory response. The granulomatous inflammation around Schistosoma mansoni eggs appears to mobilize and activate a reduced number of mesenchymal cells in comparison to the scattered necro-inflammatory reaction produced by the hepatitis C virus.

Cellular and stromal characteristics in the scirrhous hepatocellular carcinoma: Comparison with hepatocellular carcinomas and intrahepatic cholangiocarcinomas

Scirrhous hepatocellular carcinoma (SHCC) is a rare variation of HCC, for which characteristics of tumor cells and the fibrotic stroma have not been clarified in detail. The present study was therefore carried out to elucidate cytological features of tumor and stromal cells and components of the stromal extracellular matrix in 15 SHCC patients undergoing hepatectomy without preoperative transarterial embolization. Diagnosis was on the basis of a scirrhous histological pattern exceeding 50% of the tumor area. Expression of cytoplasmic and extracellular matrix proteins was compared among SHCC, HCC and intrahepatic cholangiocarcinoma (ICC) cases with immunohistochemical staining. The lesions could be histologically divided into radiating and sinusoidal types. Common stromal components of SHCC and ICC were collagen types I and III. There was no expression of laminin-5 in the stroma of SHCC, but it was present in almost all ICC cases. Tenascin-C expression was significantly lower in the SHCC cases and its distribution differed between SHCC and ICC. Matrix metalloproteinase-7 (MMP-7) expression was significantly higher in SHCC compared with HCC. Almost all stromal cells were alpha-smooth muscle actin-positive both in SHCC and ICC, whereas glial fibrillary acid protein (GFAP)-positive stromal cells were significantly more increased in ICC than in SHCC. SHCC clearly differed from HCC with respect to collagen types I, III and MMP-7 expression, and from ICC with regard to stromal components including laminin-5, tenascin-C and GFAP(+) stromal cells.

Neoplasm of hepatic stellate cells (spongiotic pericytoma): a new tumor entity in human liver

The purpose of this investigation was to classify a previously unknown tumor entity in human liver observed in a 35-year-old woman. It was characterized by an unusual accumulation of fusiform CD34-positive cells and was initially misconceived as a tumor of the liver sinusoids. The tissue was examined by light and electron microscopy and by immunocytochemical techniques with a broad spectrum of antibodies. The polycyclic tumor contained multiple nodular cell aggregates. The tumor cells possessed extensive cytoplasmic processes, rough endoplasmic reticulum, a prominent Golgi complex, and, in isolated cases, fat droplets. They expressed vimentin, CD34, CD105, CD99, CD56, and sm-actin. The matrix surrounding these cells was reactive for collagen types I, III and V, and fibronectin. The unusual aspect of this tumor is that it contained collections of cells that appeared to be hepatic stellate cells (Ito cells). It also contained hepatic cells arranged in plates, lobules, and capillarized sinuses. These findings suggest that the tumorous proliferation of hepatic stellate cells is functionally linked to the hepatocytes. It is unclear whether there is a link between the tumor and the patient's use of oral contraceptives. Referring to animal studies, different hepatocarcinogens may cause neoplastic Ito cell proliferation. The patient has remained recurrence-free during the 12 months since operation.

Evaluation of estrogenic/antiestrogenic activity of ellagic acid via the estrogen receptor subtypes ERalpha and ERbeta

Ellagic acid is a plant-derived polyphenol, possessing antioxidant, antiproliferative, and antiatherogenic properties. Whether this compound has estrogenic/antiestrogenic activity, however, remains largely unknown. To answer this question, we first investigated the ability of ellagic acid to influence the activity of the estrogen receptor subtypes ERalpha and ERbeta in HeLa cells. Cells co-transfected with an estrogen response element (ERE)-driven luciferase (Luc) reporter gene and an ERalpha- or ERbeta-expression vector were exposed to graded concentrations of ellagic acid. At low concentrations (10(-7) to 10(-9) M), this compound displayed a small but significant estrogenic activity via ERalpha, whereas it was a complete estrogen antagonist via ERbeta. Further evaluation revealed that ellagic acid was a potent antiestrogen in MCF-7 breast cancer-derived cells, increasing, like the pure estrogen antagonist ICI182780, IGFBP-3 levels. Moreover, ellagic acid induced nodule mineralization in an osteoblastic cell line (KS483), an effect that was abolished by the estrogen antagonist. Endometrium-derived epithelial cells (Ishikawa) showed no response to the natural compound by using a cell viability assay (MTT). These findings suggest that ellagic acid may be a natural selective estrogen receptor modulator (SERM).

Immortalization of pancreatic stellate cells as an in vitro model of pancreatic fibrosis: deactivation is induced by matrigel and N-acetylcysteine

Tissue fibrosis is one of the characteristics of chronic pancreatitis and pancreatic adenocarcinoma. Activated pancreatic stellate cells (PSC) play a central role in this process. However, analysis of the molecular mechanisms leading to PSC activation is hampered by the lack of an established human PSC line. To overcome this problem, we immortalized and characterized primary human PSC. The cells were isolated by the outgrowth method and were immortalized by transfection with SV40 large T antigen and human telomerase (hTERT). Primary human PSC served as controls. An immortalized line, RLT-PSC, was analyzed for the expression of stellate cell markers. Moreover, the effects of transforming growth factor beta 1(TGFbeta1) or platelet-derived growth factor stimulation and of cultivation on basement membrane components or N-acetylcysteine (NAC) treatment on gene and protein expression and proliferation were analyzed. Immortal RLT-PSC cells retained the phenotype of activated PSC proven by the expression of alpha-smooth muscle actin (alphaSMA), vimentin, desmin and glial fibrillary acidic protein (GFAP). TGFbeta1 treatment upregulated the expression of alphaSMA, collagen type I (Col I), fibronectin and TGFbeta1. Incubation of RLT-PSC cells and primary human activated PSC on Matrigel plus NAC treatment resulted in a deactivated phenotype as evidenced by a decrease of alphaSMA, connective tissue growth factor and Col I expression and by a decreased proliferation of the cells. Moreover, this treatment restored the ability of the cells to store vitamin A in cytoplasmic vesicles. In conclusion, we have established an immortal pancreatic stellate cell line, without changing the characteristic phenotype. Importantly, we were able to demonstrate that besides soluble factors, the matrix surrounding PSC plays a pivotal role in the maintenance of the activation process of PSC. Cultivation of activated PSC on a reconstituted basement membrane plus treatment with NAC was able to deactivate the cells, thus pointing to the possibility of an antifibrosis therapy in chronic pancreatitis.

Expression of basic fibroblast growth factor in rat liver fibrosis and hepatic stellate cells

The expression of basic fibroblast growth factor (bFGF) in rat liver fibrosis and hepatic stellate cells (HSCs) and the relationship between the expression of bFGF and rat liver fibrogenesis were studied. Sixty male SD rats (230-260 g) were divided into 4 groups randomly (the 0 week group, 1 week group, 4 week group and 8 week group). Liver fibrosis was induced by subcutaneous injection of carbon tetrachloride. The sections of rats' liver in each group were tested by Van-Gieson (V-G) staining and immunohistochemistry. The expression of bFGF mRNA was detected by reverse transcription polymerase chain reaction (RT-PCR). HSCs were isolated by the combined methods of collagenase IV perfusion and density gradient centrifugation. The expression of bFGF protein in cultured HSCs was detected by Western blot. Images of immunohistochemistry detection, agarose gel electrophoresis of RT-PCR and SDS-polyacrylamide gel electrophoresis of Western blot were analyzed semiquantitatively by image-analyzing system. The results were analyzed by statistics. The results showed that the fibers were gradually increased in the sections of rat liver with the prolongation of the model induction. At the end of the 8th weeks, liver fibrosis was formed. The expression of bFGF detected by immunohistochemistry showed a similar tendency of gradual increase. At the end of the 8th weeks, the bFGF expression could be observed in many regions in sections and the strongest expression was in interstitial cells including HSCs and some hepatocytes in regions around the portal area and central veins. Also there was moderate expression widely in extracellular matrix (ECM). In RT-PCR detection and Western blot detection of HSCs cultured in vitro, the similar tendency of gradual increase was evident either. It is suggested that bFGF is related with liver fibrosis of rats closely and may be a fibrogenesis factor of liver. bFGF possibly regulates liver fibrogenesis through regulating metabolism of extracellular matrix (ECM) by autocrine and paracrine stimulation.