Trisomy 7 in nonneoplastic focal steatosis of the liver.

Cytogenetic analysis of short-term cultures of a nonneoplastic focal steatosis of the liver showed trisomy 7 as the sole chromosomal change. This finding, especially when viewed in light of previous reports describing +7 in nonneoplastic tissues, strongly suggests that trisomy 7 cannot be considered a tumor-specific abnormality when it occurs as the only change. The cell type in which +7 is present is not yet known.     

Interleukin-17 exacerbates hepatic steatosis and inflammation in non-alcoholic fatty liver disease

Mechanisms associated with the progression of simple steatosis to non-alcoholic fatty liver disease (NAFLD) remain undefined. Regulatory T cells (T(regs)) play a critical role in regulating inflammatory processes in non-alcoholic steatohepatitis (NASH) and because T helper type 17 (Th17) functionally oppose T(reg)-mediated responses, this study focused on characterizing the role of Th17 cells using a NAFLD mouse model. C57BL/6 mice were fed either a normal diet (ND) or high fat (HF) diet for 8 weeks. Mice in the HF group had a significantly higher frequency of liver Th17 cells compared to ND-fed mice. Neutralization of interleukin (IL)-17 in HF mice ameliorated lipopolysaccharide (LPS)-induced liver injury reflected by decreased serum alanine aminotransferase (ALT) levels and reduced inflammatory cell infiltrates in the liver. In vitro, HepG2 cells cultured in the presence of free fatty acids (FFA; oleic acid and palmitic acid) for 24 h and IL-17 developed steatosis via insulin-signalling pathway interference. IL-17 and FFAs synergized to induce IL-6 production by HepG2 cells and murine primary hepatocytes which, in combination with transforming growth factor (TGF-β), expanded Th17 cells. It is likely that a similar process occurs in NASH patients, as there were significant levels of IL-17(+) cell infiltrates in NASH patient livers. The hepatic expression of Th17 cell-related genes [retinoid-related orphan receptor gamma (ROR)γt, IL-17, IL-21 and IL-23] was also increased significantly in NASH patients compared to healthy controls. Th17 cells and IL-17 were associated with hepatic steatosis and proinflammatory response in NAFLD and facilitated the transition from simple steatosis to steatohepatitis. Strategies designed to alter the balance between Th17 cells and T(regs) should be explored as a means of preventing progression to NASH and advanced liver diseases in NAFLD patients.     

Nonalcoholic fatty liver disease: molecular mechanisms for the hepatic steatosis

Liver plays a central role in the biogenesis of major metabolites including glucose, fatty acids, and cholesterol. Increased incidence of obesity in the modern society promotes insulin resistance in the peripheral tissues in humans, and could cause severe metabolic disorders by inducing accumulation of lipid in the liver, resulting in the progression of non-alcoholic fatty liver disease (NAFLD). NAFLD, which is characterized by increased fat depots in the liver, could precede more severe diseases such as non-alcoholic steatohepatitis (NASH), cirrhosis, and in some cases hepatocellular carcinoma. Accumulation of lipid in the liver can be traced by increased uptake of free fatty acids into the liver, impaired fatty acid beta oxidation, or the increased incidence of de novo lipogenesis. In this review, I would like to focus on the roles of individual pathways that contribute to the hepatic steatosis as a precursor for the NAFLD.     

Community participation in the treatment development process using community development teams.

Little literature exists about methods for adapting research-based treatments to typical practice settings. This report describes a 2-step process and associated methods used to adapt a school-based treatment program for middle-school youth with attention deficit hyperactivity disorder (ADHD) that operates in a controlled setting to one that can operate in a typical practice setting. Step 1 included a feasibility study that yielded important findings regarding potential obstacles to successful implementation. These data, along with original treatment manuals and literature on treatments for youth with ADHD, were utilized for Step 2--the Community Development Team (CDT) process. Data collected about the CDT process indicate that its strengths outweigh potential limitations. These methods are discussed in the context of successful collaborative procedures for developing and evaluating research-based treatments in practice settings.     

Differences in gallstone structure in primary common bile duct lithiasis and gallbladder lithiasis

Summary Some differences between gallbladder lithiasis and primary common bile duct lithiasis are described. Microbiological cultures and biochemical analyses were carried out on the bile of two groups of patients: 27 suffering from gallbladder and 5 from primary common duct lithiasis. The microstructure and composition of gallstones were also examined by polarized light microscopy and X-ray diffraction. Women predominated in gallbladder lithiasis but not in primary common duct lithiasis group (P<0.05) and body weight was higher in the former group (P<0.02). Primary common duct lithiasis patients had a higher, although not significant, incidence of duodenal diverticulosis (P=0.15), and a higher incidence ofE. coli-positive cultures in bile (P<0.001). No significant difference in the biochemical composition of the bile was found between the groups. Brown pigment stones predominated in primary common duct lithiasis, while cholesterol stones did in gallbladder and secondary common duct lithiasis (P<0.0001). Stones formed in the gallbladder generally show linear, radial growths of cholesterol crystals, while those from the common duct present a polystratified, concentric deposition of microgranules composed mainly of pigmentary salts.These differences should be taken into account as additional criteria in the differential diagnosis between primary and secondary common duct lithiasis, as the classical criteria for diagnosing of the former greatly underestimate its actual incidence. The distinction between primary and secondary common duct lithiasis is of practical significance, since each entity requires different treatment.Abbreviations CBD common bile duct - CBDL common bile duct lithiasis - ERCP endoscopic retrograde cholangiopancreatography - GBL gallbladder lithiasis - HDL high density lipoproteins - PCBDL primary common bile duct lithiasis - SCBDL secondary common bile duct lithiasis - SGOT serum glutamic-oxalacetic transaminase - SGPT serum glutamic-pyruvic transaminase     

Inflammatory liver steatosis caused by IL-12 and IL-18.

Acute fatty degeneration in the liver is caused by various agents, such as aspirin, valproic acid, and ibuprofen, that directly inhibit mitochondrial beta-oxidation of fatty acid and oxidative phosphorylation. Endogenous molecules, such as cytokines and hormones, are also known to mediate microvesicular steatosis in liver failure. In this study, we examined how interleukin-12 (IL-12) and IL-18 cause steatosis in the liver. Administration of these cytokines in combination caused marked hepatosteatosis and weight loss in mice. There were marked increases in levels of interferon-gamma (IFN-gamma), nitrite (NO(2)/NO(3)), and fibrinogen in the circulation in these mice. On the other hand, the ATP concentration and blood flow in the liver were significantly reduced. These changes, except the production of IFN-gamma and NO, were partially inhibited by Z-VAD-fmk, a synthetic tripeptide inhibitor for NO-induced caspases. These results indicate that IL-12 and IL-18 may mediate inflammatory hepatosteatosis through impairment of the microcirculation, which leads to mitochondrial dysfunction in hepatocytes.     

Frequency of nonalcoholic fatty liver disease and degree of hepatic steatosis in African-American patients

BACKGROUND: This retrospective study evaluates the degree and distribution of hepatic steatosis in predominantly African-American patients who had liver biopsies over a period of five years in our institution. METHOD: A search in the pathology registry of Howard University Hospital was performed for the presence of fat in liver biopsies. Each biopsy was assessed. RESULTS: Of the 320 liver biopsies that were reviewed, 61 were found to have steatosis. Fifty-six of the 61 patients were African-American. The mean body mass index in those African-American patients was found to be 30. Grade-1 steatosis was found in 16 patients, grade 2 in 22 patients, grade 3 in 14 patients and nine patients had grade-4 steatosis. Four patients fulfilled the criteria for the diagnosis of nonalcoholic fatty liver disease (NAFLD). All four patients had simple steatosis without any inflammation. The frequency of NAFLD in our study population was found to be <2%. Nonalcoholic steatohepatitis was not found in any of our study population. Dyslipidemia was found in all four patients with steatosis. CONCLUSION: NAFLD has a low prevalence in African-American patients. Nonalcoholic steatohepatitis was not found in any of the African-American patients seen at our institution.     

Epidermal participation in post-burn hypertrophic scar development

 The reconstruction of epidermal architecture over time in normotrophic and hypertrophic scars in untransplanted, spontaneously healed partial-thickness burns has scarcely been studied, unlike the regeneration of epidermal grafts used to cover burn wounds and the regeneration of the dermis during hypertrophic scarring. The expression of markers of epidermal proliferation, differentiation and activation in normotrophic and hypertrophic scars in spontaneously healed partial-thickness burns was assessed and compared with the expression of these markers in normal control skin of healthy persons to determine whether hypertrophic scarring is associated with abnormalities in the phenotype of keratinocytes. Punch biopsies were taken both of partial-thickness burns after re-epithelialisation and of matched unburned skin. At 4 and 7 months post-burn, biopsies were taken of normotrophic and hypertrophic scars that had developed in these wounds. The biopsies were analysed using immunostaining for markers of keratinocyte proliferation, differentiation and activation (keratins 5, 10, 16 and 17, filaggrin, transglutaminase and CD36). We observed a higher expression of markers for proliferation, differentiation and activation in the epidermis of scars at 1 month post-burn than in normal control skin of healthy persons. There was a striking difference between normotrophic and hypertrophic scars at 4 months post-burn. Keratinocytes in hypertrophic scars displayed a higher level of proliferation, differentiation and activation than did normotrophic scars. At 7 months post-burn all keratinocyte proliferation and differentiation markers showed normal expression, but the activation marker CD36 remained upregulated in both normotrophic and hypertrophic scars. Surprisingly, in matched unburned skin of burn patients, a state of hyperactivation was observed at 1 month. Our results suggest that keratinocytes may be involved in the pathogenesis of hypertrophic scarring. Received: 16 September 1998 / Accepted: 28 September 1998     

Hepatocyte proliferation is the possible mechanism for the transient decrease in liver injury during steatosis stage of alcoholic liver disease

Steatosis is a frequent pathologic stage in alcoholic liver disease (ALD). Although the mechanisms for increased susceptibility of steatotic liver to injury have been postulated, the ability of these hepatocytes to proliferate and withstand injury is unknown. There are conflicting reports on the status of hepatocyte regeneration following chronic alcohol ingestion. Hence, the objective of this study was to investigate the temporal dynamics between the pattern of liver injury and hepatocyte proliferation during the steatosis stage of ALD. Alcoholic steatosis was induced in male Sprague-Dawley rats by feeding an ethanol (EtOH)-containing Lieber-DeCarli liquid diet for a period of 5 weeks. Microvesicular steatosis was evident in H&E sections by three weeks in the EtOH-treated rats, which further developed into panlobular macrovesicular steatosis by 5 weeks. Plasma transaminase activities indicated progressive increase in liver injury peaking at 3 weeks with significant but mild decrease at 4 and 5 weeks. CYP2E1 protein and activity was significantly increased in EtOH-fed rats as measured by Western blot and pNP hydroxylation assay. PCNA analysis of liver sections indicated that EtOH-treated rats had a significantly higher number of cells in S phase of cell division at weeks 1 (3.20 +/- 0.19), 2 (7.03 +/- 0.92), and 3 (4.23 +/- 1.41) when compared to controls (1.5 +/- 0.22). NF-kappaB DNA binding and Cyclin D1 proteins increased significantly in the EtOH-treated rats corresponding with enhanced hepatic proliferation. These data suggest the transient decline in liver injury during alcoholic steatosis is due to enhanced NF-kappaB-dependent hepatocyte proliferation.     

Comparing morphometric, biochemical, and visual measurements of macrovesicular steatosis of liver

The degree of macrovesicular steatosis is typically evaluated in liver biopsies by visual estimation, which is subject to intraobserver and interobserver variations. Computer morphometry and biochemical measurement may provide more accurate results. Our aim was to develop a morphometry method and compare its results with visual and biochemical measurements. Twenty-six fresh frozen liver specimens were each divided into 4 aliquots. Three aliquots were processed biochemically to extract fat, and the fat content was defined as the weight percentage of fat. One aliquot was fixed in formalin, from which hematoxylin and eosin slides were made and reviewed by 3 pathologists to estimate fat content. Digital images of slides were analyzed by computer morphometry, which defined fat content as the percentage of area occupied by fat droplets. The results showed that individually, each method produced highly precise and reproducible measurements. Compared with each other, they showed very strong correlations (correlation coefficient r = 0.81-0.95). The range of fat content in all 26 specimens was 2.2% to 15% by biochemical, 0.8% to 82.5% by visual, and 0.3% to 19.6% by morphometry method. Visual estimation appeared to have a systematic bias, giving results nearly 4-fold higher than other methods. This may be because visual estimation denotes the fraction of hepatocytes containing fat droplets, instead of the true fraction of fat. Strong correlations between different methods suggest that all 3 are valid methods for measuring steatosis. Computer morphometry is easy to implement and not affected by the bias seen in visual estimation. It may serve as a potential supplemental or alternative method.     

Lactobacillus attenuates progression of nonalcoholic fatty liver disease by lowering cholesterol and steatosis

Background/AimsNonalcoholic fatty liver disease (NAFLD) is closely related to gut-microbiome. There is a paucity of research on which strains of gut microbiota affect the progression of NAFLD. This study explored the NAFLD-associated microbiome in humans and the role of Lactobacillus in the progression of NAFLD in mice.MethodsThe gut microbiome was analyzed via next-generation sequencing in healthy people (n=37) and NAFLD patients with elevated liver enzymes (n=57). Six-week-old male C57BL/6J mice were separated into six groups (n=10 per group; normal, Western, and four Western diet + strains [10⁹ colony-forming units/g for 8 weeks; L. acidophilus, L. fermentum, L. paracasei, and L. plantarum]). Liver/body weight ratio, liver pathology, serum analysis, and metagenomics in the mice were examined.ResultsCompared to healthy subjects (1.6±4.3), NAFLD patients showed an elevated Firmicutes/Bacteroidetes ratio (25.0±29.0) and a reduced composition of Akkermansia and L. murinus (P<0.05). In the animal experiment, L. acidophilus group was associated with a significant reduction in liver/body weight ratio (5.5±0.4) compared to the Western group (6.2±0.6) (P<0.05). L. acidophilus (41.0±8.6), L. fermentum (44.3±12.6), and L. plantarum (39.0±7.6) groups showed decreased cholesterol levels compared to the Western group (85.7±8.6) (P<0.05). In comparison of steatosis, L. acidophilus (1.9±0.6), L. plantarum (2.4±0.7), and L. paracasei (2.0±0.9) groups showed significant improvement of steatosis compared to the Western group (2.6±0.5) (P<0.05).ConclusionsIngestion of Lactobacillus, such as L. acidophilus, L. fermentum, and L. plantarum, ameliorates the progression of nonalcoholic steatosis by lowering cholesterol. The use of Lactobacillus can be considered as a useful strategy for the treatment of NAFLD.     

Exploration of global gene expression in human liver steatosis by high-density oligonucleotide microarray

Understanding the molecular mechanisms underlying fatty liver disease (FLD) in humans is of major importance. We used high-density oligonucleotide microarrays (22.3 K) to assess the mechanisms responsible for the development of human liver steatosis. We compared global gene expression in normal (n=9) and steatotic (n=9) livers without histological signs of inflammation or fibrosis. A total of 34 additional human samples including normal (n=11), steatosis (n=11), HCV-related steatosis (n=4) or steatohepatitis associated with alcohol consumption (n=4) or obesity (n=4) were used for immunohistochemistry or quantitative real-time PCR studies. With unsupervised classification (no gene selection), all steatotic liver samples clustered together. Using step-down maxT multiple testing procedure for controlling the Family-Wise Error-Rate at level 5%, 110 cDNAs (100 over- and 10 underexpressed) were found to be differentially expressed in steatotic and normal livers. Of them were genes involved in mitochondrial phosphorylative and oxidative metabolism. The mean ratio of mitochondrial DNA to nuclear DNA content was higher in liver steatosis compared to normal liver biopsies (1.12+/-0.14 vs 0.67+/-0.10; P=0.01). An increased expression of genes involved in inflammation (IL-1R family, TGFB) was also observed and confirmed by quantitative RT-PCR or immunochemistry. In steatohepatitis, an increase of the protein expression of mitochondrial antigens, IL-1R1, IGF2 and TGFB1 was also observed, interleukin 1 receptor being always strongly expressed in steatohepatitis linked to alcohol or obesity. In conclusion, mitochondrial alterations play a major role in the development of steatosis per se. Activation of inflammatory pathways is present at a very early stage of steatosis, even if no morphological sign of inflammation is observed.     

Quantitative assessment of fibrosis and steatosis in liver biopsies from patients with chronic hepatitis C

BACKGROUNDS: Hepatic fibrosis is one of the main consequences of liver disease. Both fibrosis and steatosis may be seen in some patients with chronic hepatitis C and alcoholic liver disease (ALD). AIMS: To quantitate fibrosis and steatosis by stereological and morphometric techniques in patients with chronic hepatitis C and compare the results with a control group of patients with ALD. In addition, to correlate the quantitative features of fibrosis with the Ishak modified histological score. MATERIALS AND METHODS: Needle liver biopsies from 86 patients with chronic hepatitis C and from 32 patients with alcoholic liver disease (disease controls) were analysed by stereological and morphometric analyses using the Prodit 5.2 system. Haematoxylin and eosin and Picro-Mallory stained sections were used. The area fractions (A(A)) of fibrosis, steatosis, parenchyma, and other structures (bile duct and central vein areas) were assessed by stereological method. The mean diameters of fat globules were determined by morphometric analysis. RESULTS: Significant differences were found in the A(A) of fibrosis, including fibrosis within portal tract areas, between chronic hepatitis C patients and those with ALD (mean (SD): 19.14 (10.59) v 15.97 (12.51)). Portal and periportal (zone 1) fibrosis was significantly higher (p = 0.00004) in patients with chronic hepatitis C compared with the control group (mean (SD): 9.04 (6.37) v 3.59 (3.16)). Pericentral fibrosis (zone 3) occurred in both groups but was significantly more pronounced in patients with ALD. These results correlate well with the modified Ishak scoring system. However, in patients with cirrhosis (stage 6) with chronic hepatitis C the A(A) of fibrosis varied between 20% and 74%. The diameter of fat globules was significantly lower in patients with hepatitis C (p = 0.00002) than the ALD group (mean (SD): 14.44 (3.45) v 18.4 (3.32)). Microglobules were more frequent in patients with chronic hepatitis C than in patients with ALD. In patients with chronic hepatitis C, the fat globules had a zonal distribution in comparison with pan steatosis in ALD. CONCLUSION: Quantitative, stereological techniques are simple and reliable for evaluating hepatic fibrosis and steatosis in chronic hepatitis C. They are most useful for assessing the origin, location, and the stage of fibrosis. Stereology and morphometry are recommended for the quantitation of fibrosis and steatosis, particularly for the evaluation of new treatment strategies in patients with chronic hepatitis C.