Is cirrhosis of the liver reversible?

Evaluating the clinical value of MRI multi-model diffusion-weighted imaging on liver fibrosis in chronic hepatitis B patients

PURPOSE

To explore the value of various diffusion parameters obtained from monoexponential, biexponential, and stretched exponential in assessing liver fibrosis in chronic hepatitis B (CHB).

METHODS

DWI and intravoxel incoherent motion (IVIM) MRI were performed prospectively on liver for 146 patients with CHB and 21 healthy volunteers. ADC values were obtained from monoexponential model imaging. Diffusion coefficient (D), pseudodiffusion coefficient (D*), and perfusion fraction (f) obtained by biexponential model imaging, and stretched exponential model to obtain diffusion distribution coefficient (DDC) and diffusion heterogeneity index (α). Blood draw were performed on patients to obtain AST, ALT, and PLT, and then APRI and FIB-4 index were determined based on the serological diagnostic models. The fibrosis stage was staged (S0-S4) according to the pathology of liver puncture. Independent sample t test was used to compare the parameter values between liver fibrosis group and control group. One-way ANOVA was used to compare the parameters of different liver fibrosis grades. Bonferroni test was used for correcting multiple comparisons. Spearman correlation was used to analyze the correlation between each parameter and liver fibrosis grades. ROC was used to predict the diagnostic power of each parameter for liver fibrosis stages ≥ S2 and ≥ S3.

RESULTS

ADC, D, D*, f, and DDC values were significantly different between normal control group and hepatic fibrosis group (P < 0.05). There were significant differences in ADC, D*, f, and DDC value among liver fibrosis groups (P < 0.05). D* and DDC values were moderately negatively correlated with the grades of liver fibrosis (r =  - 0.483, P < 0.001; r =  - 0.622, P < 0.001). ADC and f values were slightly negatively correlated with the grades of liver fibrosis (r =  - 0.295, P < 0.001; r =  - 0.312, P < 0.001). DDC values have the highest diagnostic efficiency in liver fibrosis stages ≥ S2 and ≥ S3. The areas under ROC curve (AUC) were 0.813 and 0.832 for ≥ S2 and ≥ S3, respectively, the sensitivity is 83.72% and 73.53%, and the specificity of 83.33% and 66.04%, which were better than APRI and FIB-4.

CONCLUSION

D* obtained from biexponential and DDC obtained from stretched exponential DWI have better value in evaluating the degree of liver fibrosis in CHB.

Magnetic Resonance Diffusion Kurtosis Imaging for Evaluating Stage of Liver Fibrosis in a Rabbit Model

RATIONALE AND OBJECTIVES

As an extension of the conventional diffusion weighted imaging, diffusion kurtosis imaging (DKI) is based on the non-Gaussian diffusion model that can inherently account for restricted water diffusion within the complex microstructure of most tissues. This study aimed to investigate association of liver DKI derived parameter with stage of liver fibrosis.

MATERIALS AND METHODS

Fifty-six healthy New Zealand white rabbits were enrolled into this study, among which 48 rabbits were randomly given carbon tetrachloride to model liver fibrosis, and 8 rabbits treated with normal saline served as control subjects. All rabbits underwent liver DKI followed by biopsy to stage fibrosis (stages F0-F4) on 6th, 8th, 10th, and 12th weekends after initiation of modeling fibrosis. Mean kurtosis (MK), fractional anisotropy (FA), and mean diffusion (MD) were derived from DKI data. Statistical analysis was to evaluate association of DKI derived parameter with stage of fibrosis.

RESULTS

FA (r = 0.512) and MK (r = 0.567) increased, and MD (r = -0.574) decreased with increasing stage of fibrosis from F0 to F4 (all p values < 0.05). Significant differences were found in all parameters between F0 and F3 or F4, F1 and F4, F0 and F1-4, and F0-1 and F2-4 (all p values < 0.05). FA and MD could distinguish between F0 from F2, MD, and MK could distinguish F1 from F3, F0-2 from F3-4, and F1-2 from F3-4, and MK and FA could distinguish F2 from F4, and F0-3 from F4 (all p values < 0.05). According to receiver operating characteristic analysis, MK could best predict stage ≥F1, ≥F2, ≥F3, and F4, and discriminate F1-2 from F3-4 with areas under receiver operating characteristic curve of 0.766-0.930.

CONCLUSION

DKI derived parameters can help stage fibrosis.

Cilostazol protects rats against alcohol-induced hepatic fibrosis via suppression of TGF-β1/CTGF activation and the cAMP/Epac1 pathway

Alcohol abuse and chronic alcohol consumption are major causes of alcoholic liver disease worldwide, particularly alcohol-induced hepatic fibrosis (AHF). Liver fibrosis is an important public health concern because of its high morbidity and mortality. The present study examined the mechanisms and effects of the phosphodiesterase III inhibitor cilostazol on AHF. Rats received alcohol infusions via gavage to induce liver fibrosis and were treated with colchicine (positive control) or cilostazol. The serum alcohol dehydrogenase (ADH) and acetaldehyde dehydrogenase (ALDH) activities and the albumin/globulin (A/G), enzymes and hyaluronic acid (HA), type III precollagen (PC III), laminin (LA), and type IV collagen (IV-C) levels were measured using commercially available kits. α-smooth muscle actin (α-SMA), collagen I and III, transforming growth factor-β1 (TGF-β1), connective tissue growth factor (CTGF), adenosine 3',5'-cyclic monophosphate (cAMP) and exchange protein directly activated by cAMP (Epac) 1/2 expression in liver tissue were measured using western blotting. The results demonstrated that cilostazol significantly increased the serum ADH and ALDH activities and decreased the liver hydroxyproline levels. Cilostazol increased the serum A/G ratio and inhibited the total serum protein, enzymes, HA, PCIII, LA and IV-C levels. Western blotting revealed that cilostazol effectively decreased liver α-SMA, collagen I and III, TGF-β1 and CTGF expression. Cilostazol significantly increased the cAMP and Epac1 levels in hepatic tissue. The present study suggests that cilostazol protects rats against AHF via suppression of TGF-β1/CTGF activation and the cAMP/Epac1 pathway.

Non-alcoholic fatty liver disease, to struggle with the strangle: Oxygen availability in fatty livers

Nonalcoholic fatty liver diseases (NAFLD) is one of the most common chronic liver disease in Western countries. Oxygen is a central component of the cellular microenvironment, which participate in the regulation of cell survival, differentiation, functions and energy metabolism. Accordingly, sufficient oxygen supply is an important factor for tissue durability, mainly in highly metabolic tissues, such as the liver. Accumulating evidence from the past few decades provides strong support for the existence of interruptions in oxygen availability in fatty livers. This outcome may be the consequence of both, impaired systemic microcirculation and cellular membrane modifications which occur under steatotic conditions. This review summarizes current knowledge regarding the main factors which can affect oxygen supply in fatty liver.

Ameliorative effects of Compound K and ginsenoside Rh1 on non-alcoholic fatty liver disease in rats

Non-alcoholic fatty liver disease (NAFLD) is a common liver disease, which has no standard treatment available. Panax notoginseng saponines (PNS) have recently been reported to protect liver against hepatocyte injury induced by ethanol or high fat diet (HFD) in rats. Compound K and ginsenoside Rh1 are the main metabolites of PNS. In this study, we evaluated the effects of CK and Rh1 on NAFLD. Rats fed HFD showed significant elevations in liver function markers, lipids, glucose tolerance, and insulin resistance. Treatment with CK or Rh1 either alone or in combination dramatically ameliorated the liver function impairment induced by HFD. Histologically, CK and Rh1 significantly reversed HFD-induced hepatocyte injury and liver fibrosis. In vitro experiments demonstrated that treatment with CK or Rh1 alone or in combination markedly induced cell apoptosis, and inhibited cell proliferation and activation in HSC-T6 cells. Additionally, CK and Rh1, either alone or in combination, also repressed the expression of fibrotic factors TIMP-1, PC-I, and PC-III. Taken together, our results demonstrate that CK and Rh1 have positive effects on NAFLD via the anti-fibrotic and hepatoprotective activity.

Autoimmune hepatitis unmasked by nimesulide

A 49-year-old woman presented at the emergency department, with acute hepatic failure, 2 weeks after taking nimesulide. Presenting with a MELD score of 25.0, the patient was transferred to a specialised liver transplant unit, with the probable diagnosis of toxic hepatitis. After a clinical improvement with supportive care and acetylcysteine, a liver biopsy was executed. The histology revealed micronodular cirrhosis associated with acute hepatitis, with features suggestive of autoimmune hepatitis. The patient was then started on azathioprine 50 mg/day and prednisolone 30 mg/day, and tapering of prednisolone was carried out in the following months. Twenty eight months after treatment, another liver biopsy was performed, showing almost full remission of the disease, with only mild fibrosis and no significant inflammatory infiltrate.

Inhibition of liver fibrosis using vitamin A-coupled liposomes to deliver matrix metalloproteinase-2 siRNA in vitro

Hepatic fibrosis is a common form of wound healing in response to chronic liver injuries and can lead to more serious complications, including mortality. It is well-established that hepatic stellate cells (HSCs) are central mediators of hepatic fibrosis, and matrix metalloproteinase-2 (MMP-2) is important in the formation of liver fibrosis. In addition, HSCs are the primary cells secreting MMP-2 and extracellular matrix, therefore, there has been increasing interest in developing agents with high selectivity towards HSCs. However, no clinical drugs based on MMP-2, directed against HSCs, have been used to prevent fibrosis. Following consideration of the abundant vitamin A (VitA) receptors expressed on the cellular membrane of HSCs, the present study constructed VitA-coupled liposomes (VitA-lips) using dicyclohexylcarbodiimide-1, 3-diaminopentane condensation, rotatory film processing and ultrasonic oscillation. The results revealed that the liposomes exhibited low cytotoxicity and a suitable binding ability to MMP-2 small interference (si)RNA. Furthermore, the liposomes effectively delivered MMP-2 siRNA to the HSC-T6 cells. When HSCs were treated with the liposomes carrying MMP-2 siRNA (VitA-lip-MMP-2 siRNA), the mRNA expression and activity of MMP-2, and the protein expression levels of α-smooth muscle actin and type I collagen were significantly reduced. These results suggested that inhibition of the expression of MMP-2 in HSC-T6 cells may contribute to preventing hepatic fibrosis, and provided experimental support to the development of specific drugs against MMP-2 to prevent fibrogenesis in chronic liver disease.

Caffeine protects against alcohol-induced liver fibrosis by dampening the cAMP/PKA/CREB pathway in rat hepatic stellate cells

Alcoholic liver fibrosis (ALF) is characterized by hyperplasia of extracellular matrix under long-term alcohol stimulation. Hepatic stellate cell (HSC) activation plays an important role in promoting hepatic fibrogenesis. Caffeine, as the main active component of coffee and tea, was widely consumed in daily life. It was always a thought that caffeine can reduce the probability of suffering from liver diseases. In this study, we attempt to validate the hypothesis that caffeine inhibits activation of HSCs which were isolated from rat ALF model. The rats were gavaged by ethanol to establish ALF model and then treated with different concentrations of caffeine or colchicine. Serum was collected to measure the contents of serum alanine aminotransferase (ALT), aspartate transaminase (AST), hyaluronic acid (HA), laminin (LN), N-terminal peptide of type III procollagen (PIIINP) and type IV collagen (CIV). Then liver tissues were obtained for hematoxylin-eosin staining and Sirius-red staining. Others were treated through liver perfusion to isolate primary rat HSCs. Interestingly, we found that caffeine significantly decreased ALT, AST, HA, LN, PIIINP and CIV levels and reversed liver fibrosis in rat ALF models. Results of immunohistochemistry, real-time PCR and western blot indicated that caffeine could reduce fibrosis and inhibit cAMP/PKA/CREB signal pathway in HSC. Caffeine has a preventive effect on ALF. The mechanism may be interpreted that caffeine inhibits the cAMP/PKA/CREB signal pathway through adenosine A2A receptors in HSC.

Expression of Septin4 in human hepatic stellate cells LX-2 stimulated by LPS

Septin4, a member of polymerizing GTP-binding proteins family, is reported to be involved in cytoskeletal organization in mitosis, apoptosis, fibrosis, and other cellular processes. Since various Septin4 expression patterns were reported in different diseases, this study aimed to investigate Septin4 expression in human LX-2 cell line stimulated by lipopolysaccharides (LPS) and attempted to clarify the relationship between Septin4 and hepatic inflammatory injury and fibrosis. In this subject, human stellate cell line LX-2 was stimulated by LPS. The expression of Septin4 was analyzed by Western blot and quantitative real-time PCR. To observe the relationship among Toll-like receptor 4 (TLR4), TGF-β, and Septin4, proteins from the anti-TLR4 antibody blocked cells, as well as the TGF-β-induced cells, were analyzed by the method of Western blot. As the results, LPS could induce the alteration of α-smooth muscle actin and Septin4 expression in LX-2 cells. Septin4 expression was regulated by LPS stimulation through TLR4 and TGF-β pathway. These results therefore suggest that Septin4 may be involved in the process of activation of hepatic stellate cells by LPS stimulation. Further work would focus on the function of Septin4 in hepatic inflammatory injury and fibrosis.

Spleen dynamic contrast-enhanced magnetic resonance imaging as a new method for staging liver fibrosis in a piglet model

Objective

To explore spleen hemodynamic alteration in liver fibrosis with dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI), and to determine how to stage liver fibrosis with spleen DCE-MRI parameters.

Materials and Methods

Sixteen piglets were prospectively used to model liver fibrosis staged by liver biopsy, and underwent spleen DCE-MRI on 0, 5th, 9th, 16th and 21st weekend after modeling this disease. DCE-MRI parameters including time to peak (TTP), positive enhancement integral (PEI), maximum slope of increase (MSI) and maximum slope of decrease (MSD) of spleen were measured, and statistically analyzed to stage this disease.

Results

Spearman's rank correlation tests showed that TTP tended to increase with increasing stages of liver fibrosis (r = 0.647, P<0.001), and that PEI tended to decrease from stage 0 to 4 (r = −0.709, P<0.001). MSD increased slightly from stage 0 to 2 (P>0.05), and decreased from stage 2 to 4 (P<0.05). MSI increased from stage 0 to 1, and decreased from stage 1 to 4 (all P>0.05). Mann-Whitney tests demonstrated that TTP and PEI could classify fibrosis between stage 0 and 1–4, between 0–1 and 2–4, between 0–2 and 3–4, or between 0–3 and 4 (all P<0.01). MSD could discriminate between 0–2 and 3–4 (P = 0.006), or between 0–3 and 4 (P = 0.012). MSI could not differentiate between any two stages. Receiver operating characteristic analysis illustrated that area under receiver operating characteristic curve (AUC) of TTP was larger than of PEI for classifying stage ≥1 and ≥2 (AUC = 0.851 and 0.783, respectively). PEI could best classify stage ≥3 and 4 (AUC = 0.903 and 0.96, respectively).

Conclusion

Spleen DCE-MRI has potential to monitor spleen hemodynamic alteration and classify liver fibrosis stages.

Liver dynamic contrast-enhanced MRI for staging liver fibrosis in a piglet model

PURPOSE

To determine whether dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) could monitor progression of liver fibrosis in a piglet model, and which DCE-MRI parameter is most accurate for staging this disease.

MATERIALS AND METHODS

Sixteen piglets were prospectively used to model liver fibrosis and underwent liver DCE-MRI followed by biopsy on the 0, 5th, 9th, 16th, and 21st weekends after modeling of fibrosis. Time of peak (TOP), time to peak (TTP), positive enhancement integral (PEI), maximum slope of increase (MSI), and maximum slope of decrease (MSD) were measured and statistically analyzed for the monitoring and staging.

RESULTS

As fibrosis progresses, TOP and TTP tended to increase, whereas MSI, MSD, and PEI tended to decrease (all P < 0.05). TOP, TTP, and MSI could discriminate fibrosis stage 0 from 1-4, 0-1 from 2-4, 0-2 from 3-4, and 0-3 from 4; PEI could distinguish the above-mentioned stages except 0-3 from 4; and MSD could distinguish stage 0-3 from 4, and 0 from 1-4 (all P < 0.05). For predicting stage ≥1, ≥2, and ≥3, the area under receiver operating characteristic curve (AUC) of MSI was largest among all parameters; for stage 4 AUC of TTP was largest.

CONCLUSION

DCE-MRI has the potential to dynamically stage progression of liver fibrosis.

Alleviation of Dimethylnitrosamine-Induced Liver Injury and Fibrosis by Supplementation of Anabasis articulata Extract in Rats

Anabasis articulata (Forssk) Moq. (Chenopodiaceae) is an herb, grows in Egypt, and used in folk medicine to treat diabetes, fever, and kidney infections. The protective and therapeutic effects of the ethanol extract of A. articulata aerial parts were evaluated against dimethylnitrosamine (DMN)-induced liver fibrosis, compared with the standard drug, silymarin. Hepatic hydroxyproline content, serum transforming growth factor-β1 (TGF-β1), interleukin 10 (IL-10) and fructosamine were measured as liver fibrosis markers. Hepatic malondialdehyde (MDA), nitric oxide (NO), catalase (CAT), glutathione reductase (GR) and glutathione content (GSH) were measured as oxidant/antioxidant markers. Parallel histopathological investigations were also performed. Protective and therapeutic administration of A. articulata (100 mg/kg daily for 4 weeks), markedly prevented DMN-induced loss in body and liver weights. The extract significantly inhibited the elevation of hepatic hydroxyproline, NO and MDA (P < 0.05), as well as serum fructosamine, and TGF-β1 (P < 0.05) induced by DMN while it restored IL-10 to normal level in both protective and therapeutic groups. Furthermore, A. articulata prevented the depletion in CAT, GR, and GSH levels (P ≤ 0.05). In addition, oral administration of A. articulata extract and silymarin to both protective and therapeutic groups reduced the increase in liver function enzyme activities; alanine and aspartate amintransferases, gamma-glutamyl transferase in addition to alkaline phosphatase, and caused significant increase in serum albumin concentration as compared to DMN group. These data corresponded closely with those obtained for the drug silymarin. Histopathological studies confirmed the biochemical data and revealed remarkable improvement in liver architecture. Thus, it could be concluded that, A. articulata extract exhibited in vivo hepatoprotective and therapeutic effects against DMN-induced liver injury and may act as a useful agent in controlling the progression of hepatic fibrosis through reduction of oxidative stress and improving liver function.

Bicluster and pathway enrichment analysis of HCV-induced cirrhosis and hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is the sixth most common cancer worldwide and the most common form of liver cancer. However, while it is associated frequently with hepatitis C virus (HCV) there is only an elementary understanding of its molecular pathogenesis.

METHODS

To gain insight into the molecular mechanisms of HCV-induced hepatocarcinogenesis, we performed microarray analysis on 75 surgical liver samples from 48 HCV-infected patients.

RESULTS

There were 395 differentially expressed genes between cirrhotic samples and HCC samples. Of these, 125 genes were up-regulated and 270 genes were down-regulated. We performed pathway enrichment analysis and screened as described previously.

CONCLUSIONS

The differentially expressed genes might be involved in hepatocarcinogenesis through upregulating the pathways of ECM-receptor interaction, focal adhesion, cell adhesion molecules and other cancer-related pathways, and downregulating the pathways of "complement and coagulation cascades". We hope our results could aid in seeking of therapeutic targets for HCV-induced hepatocellular carcinoma.

In vivo (1)H-MRS hepatic lipid profiling in nonalcoholic fatty liver disease: an animal study at 9.4 T

The applicability of the in vivo proton magnetic resonance spectroscopy hepatic lipid profiling (MR-HLP) technique in nonalcoholic fatty liver disease was investigated. Using magnetic resonance spectroscopy, the relative fractions of diunsaturated (fdi), monounsaturated (fmono), and saturated (fsat) fatty acids as well as total hepatic lipid content were estimated in the livers of 8 control and 23 CCl4-treated rats at 9.4 T. The mean steatosis, necrosis, inflammation, and fibrosis scores of the treated group were all significantly higher than those of the control group (P < 0.01). There was a strong correlation between the histopathologic parameters and the MR-HLP parameters (r = 0.775, P < 0.01) where both steatosis and fibrosis are positively correlated with fmono and negatively correlated with fdi. Both necrosis and inflammation, however, were not correlated with any of the MR-HLP parameters. Hepatic lipid composition appears to be changed in association with the severity of steatosis and fibrosis in nonalcoholic fatty liver disease, and these changes can be depicted in vivo by using the MR-HLP method at 9.4 T. Thus, while it may not likely be that MR-HLP helps differentiate between steatohepatitis in its early stages and simple steatosis, these findings altogether are in support of potential applicability of in vivo MR-HLP at high field in nonalcoholic fatty liver disease.

Correlation Between Sonographic Portal Vein Diameter and Flow Velocity With the Clinical Scoring Systems MELD and CTP in Cirrhotic Patients: Is There a Relationship?

Background

Liver cirrhosis is defined as a chronic disease of the liver with destruction of the hepatic parenchymal cells. The aim of the current study was to investigate the correlation between sonographic portal vein diameter (PVD) as well as portal flow velocity (PFV) with the clinical scoring systems; CTP and MELD in cirrhotic patients.

Methods

In this cross sectional study, convenience sampling enrolled 108 patients, diagnosed with liver cirrhosis. Blood samples were taken and all patients subsequently underwent Doppler sonography to determine mean portal vein velocity and diameter.

Results

All 108 patients (66 males and 42 females) were enrolled in study. The mean age (± SD) was 50.9 ± 17.6 years (range 13 - 85). The results of the present work revealed weak +ve correlation between MELD and CHILD scores (r = 0.629; P = 0.01). Moreover, the mean PVD showed a little or no +ve correlation with both MELD and CHILD scores (r = 0.216, P = 0.05) and (r = 0.241, P = 0.05) respectively. However, the mean PFV showed no statistical significant relationship with MELD score (P = 0.41).

Conclusion

Sonographic portal vein parameters cannot be a substitute for clinical grading and staging of cirrhosis; and we cannot propose it as a single acceptable diagnostic indicator in grading liver cirrhosis with accuracy.

Evaluation of the spontaneous reversibility of carbon tetrachloride-induced liver cirrhosis in rabbits

There is a general consensus that liver fibrosis in humans is potentially reversible, while scepticism prevails on the concept that cirrhosis can be truly reversed. The availability of suitable experimental models is fundamental for disease research. The experimental murine model of liver cirrhosis induced by carbon tetrachloride (CCl(4)) reproduces both the histological picture of the postnecrotic cirrhosis and its biochemical and clinical parameters. Normal hepatic structure is modified by formation of regeneration nodules. Fibrosis represents a morphological element of disease and an effect of hepatocyte necrosis. However, the relevance for research of this well-established model of liver cirrhosis is hampered by some spontaneous cirrhosis regression reported in mice and rats. It has been reported that CCl(4) also induces experimental liver cirrhosis in rabbits, but it is not known whether the process is reversible in this species. The aim of our study was to investigate this question. Male New Zealand White rabbits were treated intragastrically with CCl(4) or the vehicle only for 19 weeks and groups were sacrificed three and five months after treatment interruption. Cirrhotic and control livers were processed for routine light microscopy and for morphometric study of fibrosis by semiquantitative evaluation. The degree of fibrosis was based on the Knodell's scoring system.

Augmenter of liver regeneration (ALR) gene therapy attenuates CCl₄-induced liver injury and fibrosis in rats

Liver fibrosis represents a process of healing and scarring in response to chronic liver injury. Augmenter of liver regeneration (ALR) has been shown to protect hepatocytes from various toxins. The aim of this study was to investigate the effects of ALR gene therapy on liver injury and fibrosis induced by CCl(4) in rats and further explore the underlying mechanisms. Human ALR expression plasmid was delivered via the tail vein. ALR gene therapy might protect the liver from CCl(4)-induced injury and fibrogenesis by attenuating the mitochondrial dysfunction, suppressing oxidative stress, and inhibiting activation of HSCs. This report demonstrated that ALR gene therapy protected against the ATP loss, increased the activity of ATPase, decreased intrahepatic reactive oxygen species level, and down-regulated transforming growth factor-β1, platelet-derived growth factor-BB, and α-smooth muscle actin expression. Following gene transfer liver function tests were significantly improved. In brief, ALR gene therapy might be an effective therapeutic reagent for liver fibrosis with potential clinical applications.

Reactive oxygen species released from hypoxic hepatocytes regulates MMP-2 expression in hepatic stellate cells

Hypoxia is a common environmental stress factor and is associated with fibrogenesis. Matrix metalloproteinase-2 (MMP-2), produced by hepatic stellate cells (HSCs), plays an important role in liver fibrogenesis. However, inconsistent results have been reported on the impact of hypoxia on MMP-2 expression and activity in HSCs. We speculated that cell-cell interaction is involved in the regulation of MMP-2 expression and activity at low oxygen level in vivo. Therefore, in this report we investigated the mechanism by which hypoxic hepatocytes regulates MMP-2 expression in HSCs. Our results showed that the conditioned medium from hypoxia-treated rat hepatocytes strongly induced the expression of MMP-2 mRNA and protein in rat HSC-T6 cells. Reduced glutathione neutralized ROS released from hypoxic hepatocytes, leading to reduced MMP-2 expression in HSC-T6 cells. In addition, phospho-IκB-α protein level was increased in HSC-T6 cells treated with hypoxia conditioned medium, and NF-κB signaling inhibitor inhibited MMP-2 expression in HSC-T6 cells. Taken together, our data suggest that ROS is an important factor released by hypoxic hepatocytes to regulate MMP-2 expression in HSCs, and NF-κB signaling is crucially involved in ROS-induced MMP-2 expression in HSCs. Our findings suggest that strategies aimed at antagonizing the generation of ROS in hypoxic hepatocytes and inhibiting NF-κB signaling in HSCs may represent novel therapeutic options for liver fibrosis.

Advances in research of the reversal of liver fibrosis by transplantation of bone marrow mesenchymal stem cells

Bone marrow mesenchymal stem cells (BMSCs) are a group of stem cells capable of multilineage differentiation. Under given conditions, BMSCs can differentiate into a variety of cells, such as osteoblasts, chondrocytes, adipocytes, neuron-like cells and hepatocytes. In recent years, numerous studies have shown that BMSCs can not only inhibit and reduce liver fibrosis but also induce immunosuppression and immune tolerance. Therefore, transplantation of BMSCs can be used to treat end-stage liver disease.

Protective effects of astragaloside IV on porcine-serum-induced hepatic fibrosis in rats and in vitro effects on hepatic stellate cells

ETHNOPHARMACOLOGICAL RELEVANCE

Astragaloside IV is the primary pure saponin isolated from Astragalus membranaceus, one of the valuable traditional medical herbs. Antifibrotic activities of Astragalus membranaceus have been extensively proved.

AIM OF THE STUDY

To investigate the effects of astragaloside IV on hepatic stellate cells (HSCs) and hepatic fibrosis in rats induced by porcine-serum (PS).

MATERIALS AND METHODS

Liver fibrosis was induced by PS injection (0.5 ml, twice a week) for 12 weeks. Astragaloside IV (2.0, 4.0 mg kg(-1)) was administered intragastrically. Liver samples were subjected to histological and immunohistochemical studies. In vitro effects of astragaloside IV on primary cultured HSCs were detected by incorporation assays.

RESULTS

Astragaloside IV delayed the formation of liver fibrosis and decrease the serum levels of hyaluronic acid (HA), procollagen type III (PCIII) and hydroxyproline (Hyp) content in liver. The levels of transforming growth factor-beta(1) (TGF-beta(1)) in serum and expression in liver were significantly decreased by astragaloside IV. Collagen synthesis and proliferation were significantly inhibited by astragaloside IV (1.5, 3.0, 6.0, 12.0 and 24.0 mg L(-1)) in HSCs.

CONCLUSION

The results showed that astragaloside IV displays antifibrotic effects in rats induced by PS, the mechanism by which might be associated with its inhibitory effects on collagen synthesis and proliferation in HSCs.

Bone marrow stromal cells control the growth of hepatic stellate cells in vitro

Liver cirrhosis is characterized by hepatic dysfunction, with extensive accumulation of fibrous tissue in the liver. Hepatic stellate cells (HSCs) are the major source of fibrillar matrix proteins and play an important role in the progress of liver cirrhosis. In our study, the growth of HSCs is inhibited by bone marrow stromal cells (BMSCs). The inhibition is irreversible and is followed by apoptosis. The effect of BMSCs on the apoptosis of HSCs is possibly via the JNK pathway activated by nerve growth factor (NGF) and hepatocyte growth factor (HGF) secreted by BMSCs. Meanwhile, the apoptosis effect is enhanced by transforming growth factor-beta blocking.

Therapy with bone marrow cells reduces liver alterations in mice chronically infected by Schistosoma mansoni

AIM: To investigate the potential of bone marrow mononuclear cells (BM-MCs) in the regeneration of hepatic lesions induced by Schistosoma mansoni (S.mansoni) chronic infection.

METHODS: Female mice chronically infected with S.mansoni were treated with BM-MCs obtained from male green fluorescent protein (GFP) transgenic mice by intravenous or intralobular injections. Control mice received injections of saline in similar conditions. Enzyme-linked immunosorbent assay (ELISA) assay for transforming growth factor-beta (TGF-β), polymerase chain reaction (PCR) for GFP DNA, immunofluorescence and morphometric studies were performed.

RESULTS: Transplanted GFP⁺ cells migrated to granuloma areas and reduced the percentage of liver fibrosis. The presence of donor-derived cells was confirmed by Fluorescence in situ hybridization (FISH) analysis for detection of cells bearing Y chromosome and by PCR analysis for detection of GFP DNA. The levels of TGF-β, a cytokine associated with fibrosis deposition, in liver fragments of mice submitted to therapy were reduced. The number of oval cells in liver sections of S.mansoni-infected mice increased 3-4 fold after transplantation. A partial recovery in albumin expression, which is decreased upon infection with S.mansoni, was found in livers of infected mice after cellular therapy.

CONCLUSION: In conclusion, transplanted BMCs migrate to and reduce the damage of chronic fibrotic liver lesions caused by S.mansoni.