Federico Salamone

Silibinin modulates lipid homeostasis and inhibits nuclear factor kappa B activation in experimental nonalcoholic steatohepatitis

Nonalcoholic steatohepatitis (NASH) is associated with increased liver-related mortality. Disturbances in hepatic lipid homeostasis trigger oxidative stress and inflammation (ie, lipotoxicity), leading to the progression of NASH. This study aimed at identifying whether silibinin may influence the molecular events of lipotoxicity in a mouse model of NASH. Eight-week-old db/db mice were fed a methionine-choline deficient (MCD) diet for 4 weeks and treated daily with silibinin (20 mg/kg intraperitoneally) or vehicle. Liver expression and enzyme activity of stearoyl-CoA desaturase-1 and acyl-CoA oxidase, and expression of liver fatty acid-binding protein were assessed. Hepatic levels of reactive oxygen species, thiobarbituric acid-reactive substances (TBARS), 3-nitrotyrosine (3-NT), inducible nitric oxide synthase (iNOS), and nuclear factor kappa B (NFkB) activities were also determined. Silibinin administration decreased serum alanine aminotransferase and improved liver steatosis, hepatocyte ballooning, and lobular inflammation in db/db mice fed an MCD diet. Gene expression and activity of stearoyl-CoA desaturase-1 were reduced in db/db mice fed an MCD diet compared with lean controls and were increased by silibinin; moreover, silibinin treatment induced the expression and activity of acyl-CoA oxidase and the expression of liver fatty acid-binding protein. Vehicle-treated animals displayed increased hepatic levels of reactive oxygen species and TBARS, 3-NT staining, and iNOS expression; silibinin treatment markedly decreased reactive oxygen species and TBARS and restored 3-NT and iNOS to the levels of control mice. db/db mice fed an MCD diet consistently had increased NFkB p65 and p50 binding activity; silibinin administration significantly decreased the activity of both subunits. Silibinin treatment counteracts the progression of liver injury by modulating lipid homeostasis and suppressing oxidative stress-mediated lipotoxicity and NFkB activation in experimental NASH.

Silibinin improves hepatic and myocardial injury in mice with nonalcoholic steatohepatitis

BACKGROUND Nonalcoholic fatty liver disease is a chronic metabolic disorder with significant impact on cardiovascular and liver mortality. AIMS In this study, we examined the effects of silibinin on liver and myocardium injury in an experimental model of nonalcoholic fatty liver disease. METHODS A four-week daily dose of silibinin (20 mg/kg i.p.) was administrated to db/db mice fed a methionine-choline deficient diet. Hepatic and myocardial histology, oxidative stress and inflammatory cytokines were evaluated. RESULTS Silibinin administration decreased HOMA-IR, serum ALT and markedly improved hepatic and myocardial damage. Silibinin reduced isoprostanes, 8-deoxyguanosine and nitrites/nitrates in the liver and in the heart of db/db fed the methionine-choline deficient diet, whereas glutathione levels were restored to lean mice levels in both tissues. Consistently, liver mitochondrial respiratory chain activity was significantly impaired in untreated mice and was completely restored in silibinin-treated animals. TNF-α was increased whereas IL-6 was decreased both in the liver and heart of db/db fed methionine-choline deficient diet. Silibinin reversed heart TNF-α and IL-6 expression to control mice levels. Indeed, liver JNK phosphorylation was reduced to control levels in treated animals. CONCLUSIONS This study demonstrates a combined effectiveness of silibinin on improving liver and myocardial injury in experimental nonalcoholic fatty liver disease.

Effect of silibinin on endothelial dysfunction and ADMA levels in obese diabetic mice

BackgroundCardiovascular diseases (CVD) in diabetic patients have endothelial dysfunction as a key pathogenetic event. Asymmetric dimethylarginine (ADMA), an endogenous inhibitor of nitric oxide synthase (NOS), plays a pivotal role in endothelial dysfunction. Different natural polyphenols have been shown to preserve endothelial function and prevent CVD. In this study, we assessed the effect of silibinin, a widely used flavonolignan from milk thistle, on ADMA levels and endothelial dysfunction in db/db mice.MethodsEight-week-old db/db mice were administrated a 20 mg/Kg i.p. daily dose of silibinin (n = 6) or vehicle (n = 6) for four weeks. Heterozygous lean db/m mice served as control. Plasma, aorta and liver ADMA levels were determined by ELISA. Vascular reactivity to phenilephrine (PE), acetylcholine (ACh), sodium nitroprusside (SNP) and ADMA was assessed in isolated aortic segments, in wire myograph.ResultsPlasma and aorta ADMA levels were higher in db/db than in control lean mice. Silibinin administration markedly decreased plasma ADMA; consistently, aorta ADMA was reduced in silibinin-treated animals. Plasma and aorta ADMA levels exhibited a positive correlation, whereas liver ADMA was inversely correlated with both plasma and aorta ADMA concentrations. Endothelium-(NO)-dependent vasodilatation to ACh was impaired in db/db mice and was restored in the silibinin group, in accordance with the observed reduction of plasma and vascular levels of ADMA. Endothelium-independent vasodilatation to SNP was not modified by silibinin administration; contractile tone induced in isolated aorta from db/db mice by challenging with exogenous ADMA was not affected by the treatment.ConclusionsSilibinin markedly improves endothelial dysfunction in db/db mice by reducing circulating and vascular ADMA levels. Clinical studies are warranted to assess the efficacy of silibinin for cardiovascular protection.

Moro orange juice prevents fatty liver in mice

AIM To establish if the juice of Moro, an anthocyanin-rich orange, may improve liver damage in mice with diet-induced obesity. METHODS Eight-week-old mice were fed a high-fat diet (HFD) and were administrated water or Moro juice for 12 wk. Liver morphology, gene expression of lipid transcription factors, and metabolic enzymes were assessed. RESULTS Mice fed HFD displayed increased body weight, insulin resistance and dyslipidemia. Moro juice administration limited body weight gain, enhanced insulin sensitivity, and decreased serum triglycerides and total cholesterol. Mice fed HFD showed liver steatosis associated with ballooning. Dietary Moro juice markedly improved liver steatosis by inducing the expression of peroxisome proliferator-activated receptor-α and its target gene acylCoA-oxidase, a key enzyme of lipid oxidation. Consistently, Moro juice consumption suppressed the expression of liver X receptor-α and its target gene fatty acid synthase, and restored liver glycerol-3-phosphate acyltransferase 1 activity. CONCLUSION Moro juice counteracts liver steatogenesis in mice with diet-induced obesity and thus may represent a promising dietary option for the prevention of fatty liver.

Nonalcoholic fatty liver disease: the hepatic trigger of the metabolic syndrome.

Visceral adipose tissue (VAT) is an important risk factor for obesity-related metabolic disorders. Therefore, a reduction in VAT has become a key goal in obesity management. However, VAT is correlated with intrahepatic triglyceride (IHTG) content, so it is possible that IHTG, not VAT, is a better marker of metabolic diseases. We determined the independent association of IHTG and VAT to met- abolic functions, by evaluating groups of obese subjects, who differed in IHTG content (high or normal) but matched on VAT volume or dif- fered in VAT volume (high or low) but matched on IHTG content. Sta- ble isotope tracer techniques and the euglycemic-hyperinsulinemic clamp procedure were used to assess insulin sensitivity and very- low-density lipoprotein-triglyceride (VLDL-TG) secretion rate. Tissue biopsies were obtained to evaluate cellular factors involved in ecto- pic triglyceride accumulation. Hepatic, adipose tissue, and muscle insulin sensitivities were 41%, 13%, and 36% lower (p <0.01), respec- tively, whereas VLDL-triglyceride secretion rate was almost double (p <0.001), in subjects with higher than normal IHTG content, matched on VAT. No differences in insulin sensitivity or VLDL-TG secretion were observed between subjects with different VAT vol- umes, matched on IHTG content. Adipose tissue CD36 expression was lower (p <0.05), whereas skeletal muscle CD36 expression was higher (p <0.05), in subjects with higher than normal IHTG. These data demonstrate that IHTG, not VAT, is a better marker of the met- abolic derangements associated with obesity. Furthermore, altera- tions in tissue fatty acid transport could be involved in the pathogenesis of ectopic triglyceride accumulation by redirecting plasma fatty acid uptake from adipose tissue toward other tissues. 2010 European Association for the Study of the Liver. Published

Anthocyanins-based drugs for colon cancer treatment: the nutritionist’s point of view

1. “Protocatechuic acid…has recently been measured in human plasma at concentrations far in excess of the anthocyanin consumed”. In the work, they cite [2], it was reported that protocatechuic acid (PCA) is the main human metabolite of cyanidin-3-glucoside (CyG) following to administration of blood orange juice containing mainly cyanidin-3-glucoside and cyanidin-3(6-malonyl) glucoside among anthocyanins and no trace of PCA. Anyway measured PCA was never far in excess of the anthocyanin consumed, as it accounted

Molecular Aspects of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors worldwide. The major risk factors for HCC development are now well defined and some of the multiple steps involved in hepatocarcinogenesis have been elucidated in recent years. However, no clear picture of how and in what sequence these factors interact at the molecular level has emerged yet. Malignant transformation of hepatocytes may occur as a consequence of various etiologies, such as chronic viral hepatitis, alcohol, and metabolic disorders, in the context of increased cellular turnover induced by chronic liver injury, regeneration and cirrhosis. Activation of cellular oncogenes, inactivation of tumor suppressor genes, overexpression of certain growth factors, and possibly telomerase activation and DNA mismatch repair defects may contribute to the development of HCC. Finally, aflatoxins have been shown to induce specific mutations of the p53 tumor suppressor gene, thus pointing to the contribution of environmental factors to tumor development at the molecular level.

Silybin enhances mitochondrial function and inhibits NFkB activation in murine nonalcoholic fatty liver disease

background & Aims Non Alcoholic Fatty Liver Disease (NAFLD) is a chronic liver disease with possible cirrhotic and tumorigenic evolution. Despite a number of treatment has been proposed for NAFLD, none of these is really satisfying. Silybin, a flavonolignan extracted from milk thistle, showed marked liver protecting action in a variety of liver injury and is used as hepatoprotectant. We aimed to clarify the putative therapeutic significance of silybin and to identify the molecular pathways of silybinmediated hepatoprotection in a murine model of NAFLD. Methods We explored the effect of a 4-week daily (20mg/kg i.p.) administration of silybin in 6-week-old db/db mice feeding a methionine-choline deficient (MCD) diet. We examined liver histology, hepatic lipid homeostasis, mitochondrial function, oxidative-nitrosative stress and NFkB activation in silybin-treated mice compared with untreated animals. Results Silybin markedly decreased serum ALT and liver triglycerides content. Steatosis was less severe in grade and distribution, and lobular inflammation was almost absent in silybin-treated mice. At the molecular level, silybin promoted the gene expression of key enzymes involved in free fatty acids elongation and β-oxidation and completely restores mitochondrial respiratory chain activity. Furthermore, silybin markedly decreased oxidative-nitrosative stress and inhibited NFkB p65 and p50 subunits binding activity. Conclusions In the current study we showed that silybin displayed a marked antisteatotic and anti-inflammatory effect in the db/db + MCD murine model of NAFLD. In our opinion, these findings provide the rationale for the use of silybin in the clinical management of patients with NAFLD, which will require well-designed clinical trials.