Chaoling Ren

Silymarin retards the progression of alcohol-induced hepatic fibrosis in baboons.

Goal/Background Hepatoprotective effects of silymarin in patients with alcoholic liver disease are controversial. For strict control, this was assessed in non-human primates. Study Twelve baboons were fed alcohol with or without silymarin for 3 years with a nutritionally adequate diet. Results Silymarin opposed the alcohol-induced oxidative stress (assessed by plasma 4-hydroxynonenal) and the rise in liver lipids and circulating ALT. Alcohol also increased hepatic collagen type I by 50% over the 3 years with a significant rise in mRNA for &agr;1 (I) procollagen, both prevented by silymarin. There were corresponding morphologic changes: at 36 months, 2 of 6 animals fed alcohol had cirrhosis and 2 septal fibrosis, with perivenular fibrosis in 2, whereas with alcohol + silymarin, there was only 1 cirrhosis and 1 septal fibrosis, with perivenular fibrosis in 2, and virtually no lesions in the remaining 2. Conclusions Silymarin retards the development of alcohol-induced hepatic fibrosis in baboons, consistent with several positive clinical trials. The negative outcome observed in other trials possibly reflects poor compliance resulting in irregular or low silymarin intake. Thus, in view of the innocuity of silymarin, it might be advisable in future clinical studies to insure the controlled administration of sufficient amounts of silymarin.

Adipose Differentiation‐Related Protein Is a Reliable Lipid Droplet Marker in Alcoholic Fatty Liver of Rats

BACKGROUND Adipose differentiation-related protein (ADRP) is a lipid droplet-associated protein that coats cytoplasmic lipid droplets. The present study evaluated whether alcohol feeding enhances ADRP expression and whether ADRP is a lipid droplet marker in alcoholic fatty liver of rats. Because medium-chain triglycerides (MCT) reduce alcoholic hepatosteatosis, their effects on ADRP were also evaluated. METHODS Fatty liver was induced in rats by the consumption of the Lieber-DeCarli alcohol liquid diet with or without replacement of long-chain triglycerides (LCT) by MCT (32% of calories). Immunohistochemical staining for ADRP was performed in formalin-fixed, paraffin-embedded liver sections. ADRP immunostaining was quantified by image analysis. Triacylglycerol was measured chemically. ADRP mRNA and protein were analyzed by real-time polymerase chain reaction and western blot, respectively. Double staining technique was performed to distinguish ADRP from glycogen in hepatocytes. RESULTS Alcohol feeding for 21 days increased ADRP staining in the centrilobular and mid zonal regions of the liver lobules coincident with fat deposition in the liver. Replacing LCT in the alcohol diet with MCT diminished ADRP immunostaining in parallel with reduced steatosis. MCT also attenuated the up-regulation of ADRP mRNA and protein after alcohol. In steatotic hepatocytes ADRP selectively stained the surface of macrovesicular and microvesicular lipid droplets. ADRP immunostaining quantitatively correlated with hepatic triacylglycerol levels, validating ADRP as a reliable lipid droplet marker. Compared with hematoxylin and eosin stains, ADRP was more sensitive in detecting microvesicular lipid droplets. ADRP immunostaining also distinguished lipid droplets from glycogen, as demonstrated by double staining for ADRP and glycogen. CONCLUSIONS Alcohol induction of fatty liver enhances ADRP expression and MCT oppose the alcohol effects. ADRP is a reliable and sensitive marker for lipid droplets in alcoholic fatty liver. ADRP immunostaining permits quantification of fatty change in hepatocytes and can be used as an ancillary technique in assessing the efficacy of diets or drugs against hepatosteatosis.

Cytokeratin 7 staining of hepatocytes predicts progression to more severe fibrosis in alcohol-fed baboons

BACKGROUND/AIMS Not all alcoholic patients develop severe liver disease with fibrosis progressing to cirrhosis. It is of practical importance to determine whether some markers can predict progression of liver fibrosis. METHODS We used a baboon model that mimics human alcoholic liver disease. Cytokeratin 7 and 19 expression and fat deposition were investigated in serial liver biopsies of 18 animals undergoing prolonged alcohol administration (range 2-17 years) and in four controls. Fibrosis was graded histologically and was also assessed quantitatively by image analysis. RESULTS Ten animals did not show a progression of liver disease even after 17 years of alcohol administration, but eight animals fed alcohol exhibited a progression of liver disease from no fibrosis or perivenular fibrosis to septal fibrosis or cirrhosis within 7 years. In normal liver, cytokeratin 7 and cytokeratin 19 immunostaining is restricted to bile duct cells. Hepatocellular cytokeratin 7 was observed only in those animals which progressed to more severe stages of fibrosis and it anticipated this progression by 4.2 years on average. CONCLUSIONS In alcohol-fed baboons, cytokeratin 7 staining of hepatocytes (but not cytokeratin 19, nor fat deposition) predicts with a high degree of sensitivity and specificity progression to more severe liver disease.