Non-invasive assessment of fibrosis in non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease in Western countries, and its prevalence is increasing worldwide. It currently affects approximately 30% of adults and 10% of children and adolescents. The resulting increase in the number of patients with NAFLD is expected to translate into increased numbers of patients with liver cirrhosis, and hepatocellular carcinoma. In this context, it is particularly important to identify patients at risk for progressive chronic liver disease. Currently, liver biopsy is the gold standard to diagnose non-alcoholic steatohepatitis (NASH) and to establish the presence and stage of fibrosis. Due to the remarkable increase in the prevalence of NAFLD and the concomitant efforts in developing novel therapies for patients with NASH, non-invasive, simple, reproducible, and reliable non-invasive methodologies are needed. This paper provides a concise overview of the role of non-invasive diagnostic tools for the determination of presence and extent of fibrosis in NAFLD patients, with particular emphasis on the methods currently available in clinical practice.

Silybin, a component of sylimarin, exerts anti-inflammatory and anti-fibrogenic effects on human hepatic stellate cells

BACKGROUND/AIMS

Hepatic fibrogenesis, a consequence of chronic liver tissue damage, is characterized by activation of the hepatic stellate cells (HSC). Silybin has been shown to exert anti-fibrogenic effects in animal models. However, scant information is available on the fine cellular and molecular events responsible for this effect. The aim of this study was to assess the mechanisms regulating the anti-fibrogenic and anti-inflammatory activity of Silybin.

METHODS

Experiments were performed on HSC isolated from human liver and activated by culture on plastic.

RESULTS

Silybin was able to inhibit dose-dependently (25-50 microM) growth factor-induced pro-fibrogenic actions of activated human HSC, including cell proliferation (P < 0.001), cell motility (P < 0.001), and de novo synthesis of extracellular matrix components (P < 0.05). Silybin (25-50 microM), inhibited the IL-1-induced synthesis of MCP-1 (P < 0.01) and IL-8 (P < 0.01) showing a potent anti-inflammatory activity. Silybin exerts its effects by directly inhibiting the ERK, MEK and Raf phosphorylation, reducing the activation of NHE1 (Na+/H+ exchanger, P < 0.05) and the IkBalpha phosphorylation. In addition, Silybin was confirmed to act as a potent anti-oxidant agent.

CONCLUSION

The results of the study provide molecular insights into the potential therapeutic action of Silybin in chronic liver disease. This action seems to be mostly related to a marked inhibition of the production of pro-inflammatory cytokines, a clear anti-oxidant effect and a reduction of the direct and indirect pro-fibrogenic potential of HSC.

Adenosine monophosphate-activated protein kinase modulates the activated phenotype of hepatic stellate cells

Adiponectin limits the development of liver fibrosis and activates adenosine monophosphate-activated protein kinase (AMPK). AMPK is a sensor of the cellular energy status, but its possible modulation of the fibrogenic properties of hepatic stellate cells (HSCs) has not been established. In this study, we investigated the role of AMPK activation in the biology of activated human HSCs. A time-dependent activation of AMPK was observed in response to a number of stimuli, including globular adiponectin, 5-aminoimidazole-4-carboxamide-1-beta-4-ribofuranoside (AICAR), or metformin. All these compounds significantly inhibited platelet-derived growth factor (PDGF)-stimulated proliferation and migration of human HSCs and reduced the secretion of monocyte chemoattractant protein-1. In addition, AICAR limited the secretion of type I procollagen. Knockdown of AMPK by gene silencing increased the mitogenic effects of PDGF, confirming the negative modulation exerted by this pathway on HSCs. AMPK activation did not reduce PDGF-dependent activation of extracellular signal-regulated kinase (ERK) or Akt at early time points, whereas a marked inhibition was observed 24 hours after addition of PDGF, reflecting a block in cell cycle progression. In contrast, AICAR blocked short-term phosphorylation of ribosomal S6 kinase (p70(S6K)) and 4E binding protein-1 (4EBP1), 2 downstream effectors of the mammalian target of rapamycin (mTOR) pathway, by PDGF. The ability of interleukin-a (IL-1) to activate nuclear factor kappa B (NF-kappaB) was also reduced by AICAR.

CONCLUSION

Activation of AMPK negatively modulates the activated phenotype of HSCs.

The effect of a silybin-vitamin e-phospholipid complex on nonalcoholic fatty liver disease: a pilot study

Oxidative stress leads to chronic liver damage. Silybin has been conjugated with vitamin E and phospholipids to improve its antioxidant activity. Eighty-five patients were divided into 2 groups: those affected by nonalcoholic fatty liver disease (group A) and those with HCV-related chronic hepatitis associated with nonalcoholic fatty liver disease (group B), nonresponders to treatment. The treatment consisted of silybin/vitamin E/phospholipids. After treatment, group A showed a significant reduction in ultrasonographic scores for liver steatosis. Liver enzyme levels, hyperinsulinemia, and indexes of liver fibrosis showed an improvement in treated individuals. A significant correlation among indexes of fibrosis, body mass index, insulinemia, plasma levels of transforming growth factor-beta, tumor necrosis factor-alpha, degree of steatosis, and gamma-glutamyl transpeptidase was observed. Our data suggest that silybin conjugated with vitamin E and phospholipids could be used as a complementary approach to the treatment of patients with chronic liver damage.

Treatment of patients with non-alcoholic fatty liver disease: current views and perspectives

Non-alcoholic fatty liver disease is considered a component of the metabolic syndrome associated with obesity. Problems still exist concerning non-alcoholic fatty liver disease patients in clinical practice, for example: (a) how to diagnose non-alcoholic fatty liver disease and its type; (b) how to select patients candidate to treatment; (c) how to treat selected patients. Non-alcoholic fatty liver disease includes steatosis and non-alcoholic steatohepatitis, but only non-alcoholic steatohepatitis evolves into cirrhosis and the absolute risk of mortality for non-alcoholic fatty liver disease is low. As yet, no tools, other than liver biopsy, are available to differentiate the various types of non-alcoholic fatty liver disease. Many drugs are, currently, under study to treat non-alcoholic fatty liver disease, even if well-performed trials are until necessary to define the best treatment. At the moment, the entity of the problem and the characteristics of patients frequently put the physician, in clinical practice, to choose the therapeutic approach arbitrarily which is considered more effective for each individual patient. Probably the future will consider the possibility of treating non-alcoholic fatty liver disease with more than one drug, by considering the various aspects and degree of this syndrome. Actually each physician should select the individual treatment on the basis of his/her knowledge and experience, by never forgetting the old saying 'primum non nocere'. However, the epidemiological entity of the problem, the characteristics of the patients, generally young, the frequent lack of clinical evidence of involvement of the liver, are all the factors that require vast well-performed clinical trials in order to define the best therapeutic approach for each individual patient.

The treatment of NAFLD

Nonalcoholic fatty liver disease (NAFLD) is becoming an increasing cause of chronic liver damage. The decision of start a medical treatment is based on the documented risk of progression to cirrhosis and liver cancer, when steatohepatitis (NASH) occurs. The therapy of this syndrome requires, as obviously, some considerations on the natural history of the condition, on the efficacy and safety of various therapeutic options, as well as on the costs. Treatment of patients with NAFLD has typically been focused on the management of associated conditions such as obesity, diabetes mellitus and hyperlipemia. Weight loss improves insulin sensitivity, and NASH may resolve with weight reduction. Insulin resistance seems to be the common denominator in many cases of NAFLD. Two classes of drugs have been shown to correct insulin resistance: biguanides (e.g., metformin) and thiazolidinediones (e.g., rosiglitazone and pioglitazone). The last two decades have witnessed a considerable progress in the understanding of the mechanisms respon-sible for the fibrogenic progression of chronic liver diseases. Several drugs believed to be hepatoprotective or antifibrotic agent as UDCA, betaine, vitamin E, lecithin, beta-carotene and selenium have been used in patients with NASH. Silybin is the main component of silymarin that is absorbed when linked whith a phytosome. This substance reduces in rats the lipid-peroxidation and the activaction of hepatic stellate cells. In humans, some non controlled data show that silybin is able to reduce insulin resistance, liver steatosis and plasma markers of liver fibrosis.

[Effects of a new pharmacological complex (silybin + vitamin-E + phospholipids) on some markers of the metabolic syndrome and of liver fibrosis in patients with hepatic steatosis. Preliminary study]

AIM

This open preliminary pilot study was aimed to evaluate the effect of a new pharmaceutical complex (silybin+vitamin E+phospholipids - RealSIL-IBI-Lorenzini Pharmaceutical, Italy) on some parameters of metabolic syndrome and of liver fibrosis in patients with non alcoholic fatty liver disease (NAFLD) with or without the contemporaneous presence of hepatitis C virus (HCV)-related chronic hepatitis.

METHODS

Eighty five patients were consecutively enrolled in the study and divided in 2 groups; the first group was represented by 59 patients affected by NAFLD, negative for other known causes of chronic liver damage (M/F= 39/20; median age and range: 44 years, 22-76, group A); the second group was represented by 26 patients (M/F=19/7; median age and range 51 years, 20-75, group B) with HCV-related chronic hepatitis associated to NAFLD. Adverse events and drop-outs were absent in all group and compliance at the study was absolute.

RESULTS

This open preliminary study shows that the new compound silybin+vitamin E+ phospholipids is active, in vivo, and produces some therapeutic effects in patients with different forms of chronic liver damage. In particular, it improves insulin resistance and plasma levels of markers of liver fibrosis in patients in whom these parameters are particularly altered.

CONCLUSIONS

Our data have a role of suggestion to further evaluate, through a controlled trial, a possible therapeutic use of this new compound in the management of patients with NAFLD.