Proposal for a histological scoring and grading system for non-alcoholic fatty liver disease

SQSTM1/p62 and Hepatic Mallory-Denk Body Formation in Alcohol-Associated Liver Disease

Sequestosome 1 (SQSTM1/p62; hereafter p62) is an autophagy receptor protein for selective autophagy primarily due to its direct interaction with the microtubule light chain 3 protein that specifically localizes on autophagosome membranes. As a result, impaired autophagy leads to the accumulation of p62. p62 is also a common component of many human liver disease-related cellular inclusion bodies, such as Mallory-Denk bodies, intracytoplasmic hyaline bodies, α1-antitrypsin aggregates, as well as p62 bodies and condensates. p62 also acts as an intracellular signaling hub, and it involves multiple signaling pathways, including nuclear factor erythroid 2-related factor 2, NF-κB, and the mechanistic target of rapamycin, which are critical for oxidative stress, inflammation, cell survival, metabolism, and liver tumorigenesis. This review discusses the recent insights of p62 in protein quality control, including the role of p62 in the formation and degradation of p62 stress granules and protein aggregates as well as regulation of multiple signaling pathways in the pathogenesis of alcohol-associated liver disease.

An obesogenic feedforward loop involving PPARγ, acyl-CoA binding protein and GABAA receptor

Acyl-coenzyme-A-binding protein (ACBP), also known as a diazepam-binding inhibitor (DBI), is a potent stimulator of appetite and lipogenesis. Bioinformatic analyses combined with systematic screens revealed that peroxisome proliferator-activated receptor gamma (PPARγ) is the transcription factor that best explains the ACBP/DBI upregulation in metabolically active organs including the liver and adipose tissue. The PPARγ agonist rosiglitazone-induced ACBP/DBI upregulation, as well as weight gain, that could be prevented by knockout of Acbp/Dbi in mice. Moreover, liver-specific knockdown of Pparg prevented the high-fat diet (HFD)-induced upregulation of circulating ACBP/DBI levels and reduced body weight gain. Conversely, knockout of Acbp/Dbi prevented the HFD-induced upregulation of PPARγ. Notably, a single amino acid substitution (F77I) in the γ2 subunit of gamma-aminobutyric acid A receptor (GABA_AR), which abolishes ACBP/DBI binding to this receptor, prevented the HFD-induced weight gain, as well as the HFD-induced upregulation of ACBP/DBI, GABA_AR γ2, and PPARγ. Based on these results, we postulate the existence of an obesogenic feedforward loop relying on ACBP/DBI, GABA_AR, and PPARγ. Interruption of this vicious cycle, at any level, indistinguishably mitigates HFD-induced weight gain, hepatosteatosis, and hyperglycemia.

Does the FT3-to-FT4 ratio easily predict the progression of NAFLD and NASH cirrhosis?

Background

Factors causing progression from nonalcoholic fatty liver to nonalcoholic steatohepatitis (NASH) and liver cirrhosis remain relatively unknown. We aimed to evaluate the power and effectiveness of the free triiodothyronine (FT3)-to-free thyroxine (FT4) ratio to predict non-alcoholic fatty liver disease (NAFLD)/liver fibrosis and NASH cirrhosis severity.

Methods

Patients (n = 436) with NASH-associated liver cirrhosis (n = 68), patients with liver biopsy-proven NAFLD (n = 226), or healthy participants (n = 142) were enrolled between January 2010 and January 2020. The aspartate aminotransferase-to-thrombocyte ratio (APRI), NAFLD fibrosis score, albumin–bilirubin score (ALBI), aspartate aminotransferase (AST)-to-alanine aminotransferase (ALT) ratio, FT3-to-FT4 ratio, and Fibrosis-4 (FIB-4) were calculated and evaluated.

Results

All parameters were significantly higher in NASH cirrhosis than in the healthy group. Body mass index, ALT, fasting insulin, homeostatic model assessment for insulin resistance, and triglyceride levels were significantly higher in liver biopsy-proven NAFLD than in the healthy group. The APRI, NAFLD fibrosis score, ALBI, AST-to-ALT ratio, FT3-to-FT4 ratio, and FIB-4 were significantly higher in the NASH cirrhosis group than in the healthy group. In patients with biopsy-proven NAFLD, the FT3-to-FT4 ratio was significantly lower than in the healthy group.

Conclusion

The FT3-to-FT4 ratio is an effective and useful indicator to predict NAFLD/liver fibrosis and NASH cirrhosis severity.

Carminic acid mitigates fructose-triggered hepatic steatosis by inhibition of oxidative stress and inflammatory reaction

Excessive fructose (Fru) consumption has been reported to favor nonalcoholic fatty liver disease (NAFLD). However, the molecular mechanism is still elusive, lacking effective therapeutic strategies. Carminic acid (CA), a glucosylated anthraquinone found in scale insects like Dactylopius coccus, exerts anti-tumor and anti-oxidant activities. Nevertheless, its regulatory role in Fru-induced NAFLD is still obscure. Here, the effects of CA on NAFLD in Fru-challenged mice and the underlying molecular mechanisms were explored. We found that Fru intake significantly led to insulin resistance and dyslipidemia in liver of mice, which were considerably attenuated by CA treatment through repressing endoplasmic reticulum (ER) stress. Additionally, inflammatory response induced by Fru was also attenuated by CA via the blockage of nuclear factor-κB (NF-κB), mitogen-activated protein kinases (MAPKs) and tumor necrosis factor α/TNF-α receptor (TNF-α/TNFRs) signaling pathways. Moreover, Fru-provoked oxidative stress in liver tissues was remarkably attenuated by CA mainly through improving the activation of nuclear factor erythroid 2-related factor 2 (Nrf-2). These anti-dyslipidemias, anti-inflammatory and anti-oxidant activities regulated by CA were confirmed in the isolated primary hepatocytes with Fru stimulation. Importantly, the in vitro experiments demonstrated that Fru-induced lipid accumulation was closely associated with inflammatory response and reactive oxygen species (ROS) production regulated by TNF-α and Nrf-2 signaling pathways, respectively. In conclusion, these results demonstrated that CA could be considered as a potential therapeutic strategy to attenuate metabolic disorder and NAFLD in Fru-challenged mice mainly through suppressing inflammatory response and oxidative stress.

Reversion to regular diet with alternate day fasting can cure grade-I non-alcoholic fatty liver disease (NAFLD) in high-fructose-intake-associated metabolic syndrome

Background

Non-alcoholic fatty liver disease (NAFLD) is an emerging global health problem that accompanied the obesity epidemic and is considered as the hepatic component of metabolic syndrome (MetS). Modification of lifestyle of MetS patients remains the focus to reverse and prevent progression of hepatic steatosis to NAFLD and its worsening to severe forms. The present study investigates the possible curability of metabolic syndrome -associated grade-1 NAFLD merely by alternate day fasting with or without reversion to regular diet in adult male rats. The present study was performed on 66 local strain male rats aged (6–10 m.) distributed randomly into C group (n = 12), on regular rat diet; and M group (n = 54) on high fructose- intake. On the 8th week, then rats were subjected to measurement of BW, BMI, WC, FBG, IPGTT, HDL-C, TGs, and liver histopathology, to include MetS rats randomly into four experimental groups for 4 weeks as follows: MS (n = 14); MSRD (n = 12); MSF (n = 13); and MSRDF (n = 12). On the 12th week, all rats were subjected to measurements of BW, BMI, WC, LW, LW/BW, VFW, VFW/BW, FBG, IPGTT, Ins., HOMA-IR, HbA1C, TGs, TC, LDL-C, HDL-C, CRP, Alb., bilirubin, ALT, L-MDA, and liver histopathology.

Results

On the 8th week, M group developed MerS and grade-I NAFLD with score-4 hepatosteatosis (69%). On the 12th week, MS group had grade-1 NAFLD with score-4 hepatosteatosis (82%) with significantly increased Ins., HOMA-IR, HDL-C, LW, LW/BW, L-MDA, ALT, CRP, and significantly decreased Alb. than C rats. Both MSRD and MSF groups had grade-1 NAFLD with score-3 hepatosteatosis (42%) with significantly decreased Ins., HOMA-IR, TC, LDL-C, LW, LW/BW, L-MDA, ALT, CRP, and significantly increased HDL-C and Alb. than MS group. MSRDF rats showed cure of grade-1 NAFLD and significantly decreased LW than other groups and normalized HOMA-IR, HbA1C TC, LDL-C, ALT, and CRP.

Conclusion

One month of alternate-day fasting and regular rat diet could cure grade-I NAFLD associated with Mets due to high fructose intake possibly by attenuating metabolic disorders. These two interventions might be recommended in the management of MetS patients with grade 1-NAFLD disease.

A novel histological index for evaluation of environmental enteric dysfunction identifies geographic-specific features of enteropathy among children with suboptimal growth

Background

A major limitation to understanding the etiopathogenesis of environmental enteric dysfunction (EED) is the lack of a comprehensive, reproducible histologic framework for characterizing the small bowel lesions. We hypothesized that the development of such a system will identify unique histology features for EED, and that some features might correlate with clinical severity.

Methods

Duodenal endoscopic biopsies from two cohorts where EED is prevalent (Pakistan, Zambia) and North American children with and without gluten sensitive enteropathy (GSE) were processed for routine hematoxylin & eosin (H&E) staining, and scanned to produce whole slide images (WSIs) which we shared among study pathologists via a secure web browser-based platform. A semi-quantitative scoring index composed of 11 parameters encompassing tissue injury and response patterns commonly observed in routine clinical practice was constructed by three gastrointestinal pathologists, with input from EED experts. The pathologists then read the WSIs using the EED histology index, and inter-observer reliability was assessed. The histology index was further used to identify within- and between-child variations as well as features common across and unique to each cohort, and those that correlated with host phenotype.

Results

Eight of the 11 histologic scoring parameters showed useful degrees of variation. The overall concordance across all parameters was 96% weighted agreement, kappa 0.70, and Gwet’s AC 0.93. Zambian and Pakistani tissues shared some histologic features with GSE, but most features were distinct, particularly abundance of intraepithelial lymphocytes in the Pakistani cohort, and marked villous destruction and loss of secretory cell lineages in the Zambian cohort.

Conclusions

We propose the first EED histology index for interpreting duodenal biopsies. This index should be useful in future clinical and translational studies of this widespread, poorly understood, and highly consequential disorder, which might be caused by multiple contributing processes, in different regions of the world.

The study of EED has been limited by the lack of a rigorously tested, reproducible histology index that can provide insight to the pathogenesis of this entity. In this study we report the first duodenal histology index that was developed using an unbiased approach, with excellent inter-observer reproducibility, for the study of EED. The EED histology index readily identified histologic features that are common or unique to cohorts of distinct geographic locations. Incorporating the histology index into future clinical studies will provide useful insight into the pathogenesis and for intervention strategy development.

The Combination of Metformin and Valproic Acid Has a Greater Anti-tumoral Effect on Prostate Cancer Growth In Vivo than Either Drug Alone

BACKGROUND/AIM

The hypoglycemic drug metformin (MET) and the anti-epileptic drug valproic acid (VPA) have individually shown anti-tumor effects in prostate cancer in vitro. The present study intended to investigate the efficacy of the combination of MET and VPA in prostate cancer treatment in a pre-clinical xenograft model.

MATERIALS AND METHODS

Prostate cancer cell lines (LNCaP and PC-3) were inoculated under the skin of BALB/c nude mice. The mice were treated with 200 μl/ml MET and/or 0.4% (w/v) VPA diluted in drinking water, or with vehicle control, and were monitored until the tumor volume reached 2,000 mm³ Evaluation of toxicity of the drug combination was determined in liver and kidney by histology.

RESULTS

In both LNCaP and PC-3 xenografts, MET combined with VPA significantly reduced tumor growth during the first 4 weeks following treatment, and delayed the time-to-tumor volume of 2,000 mm³ by 90 days, as compared to MET or to VPA alone, and to vehicle control. There was no significant difference in total mouse weight, liver or kidney morphology in response to combination treatment (MET+VPA) compared to MET or VPA alone and vehicle control.

CONCLUSION

The combination treatment of MET with VPA is more effective at slowing prostate tumor growth in vivo compared to either drug alone, in mouse xenografts. These pre-clinical results support previous in vitro data and also demonstrate the low toxicity of the combination of these drugs, suggesting that this may be a potential new therapy to be investigated in clinical trials for prostate cancer.

A history of obesity leaves an inflammatory fingerprint in liver and adipose tissue

BACKGROUND/OBJECTIVES

Dieting is a popular yet often ineffective way to lower body weight, as the majority of people regain most of their pre-dieting weights in a relatively short time. The underlying molecular mechanisms driving weight regain and the increased risk for metabolic disease are still incompletely understood. Here we investigate the molecular alterations inherited from a history of obesity.

METHODS

In our model, male high-fat diet (HFD)-fed obese C57BL/6J mice were switched to a low caloric chow diet, resulting in a decline of body weight to that of lean mice. We measured body composition, as well as metrics of glucose, insulin and lipid homeostasis. This was accompanied by histological and gene expression analysis of adipose tissue and liver to assess adipose tissue inflammation and hepatosteatosis. Moreover, acute hypothalamic response to (re-) exposure to HFD was assessed by qPCR.

RESULTS & CONCLUSIONS

Within 7 weeks after diet switch, most obesity-associated phenotypes, such as body mass, glucose intolerance and blood metabolite levels were reversed. However, hepatic inflammation, hepatic steatosis as well as hypertrophy and inflammation of perigonadal, but not subcutaneous, adipocytes persisted in formerly obese mice. Transcriptional profiling of liver and perigonadal fat revealed an upregulation of pathways associated with immune function and cellularity. Thus, we show that weight reduction leaves signs of inflammation in liver and perigonadal fat, indicating that persisting proinflammatory signals in liver and adipose tissue could contribute to an increased risk of formerly obese subjects to develop the metabolic syndrome upon recurring weight gain.

Choline and Fructooligosaccharide: Non-alcoholic Fatty Liver Disease, Cardiac Fat Deposition, and Oxidative Stress Markers

This study investigates the treatment of non-alcoholic fatty liver disease (NAFLD) in rats with choline and fructooligosaccharide (FOS). The healthy control group received standard diet. The other three groups consisted of animals with NAFLD. Group E_str received standard diet; group E_cho received standard diet plus choline (3 g/100 g diet); and group E_fos received standard diet plus FOS (10 g/100 g diet). Food intake, weight, urinary nitrogen, urinary ammonia, total cholesterol, serum triacylglyceride, liver and heart weights, tissue nitrogen, tissue fat, vitamin E, TBARS, and reduced glutathione (GSH) were measured in hepatic and heart tissue. Choline and FOS treatments resulted in total mean fat reduction in liver and heart tissue of 0.2 and 1.7 g, respectively. Both treatments were equally effective in reducing hepatic and cardiac steatosis. There were no differences in the TBARS level among experimental and control groups, indicating that the proposed treatments had no added protection against free radicals. While all experimental groups had increased vitamin E and GSH levels, choline treatment led to a significant increase compared to control.

Smad3 deficiency ameliorates hepatic fibrogenesis through the expression of senescence marker protein-30, an antioxidant-related protein

Smad3 is a key mediator of the transforming growth factor (TGF)-β1 signaling pathway that plays central role in inflammation and fibrosis. In present study, we evaluated the effect of Smad3 deficiency in Smad3-/- mice with carbon tetrachloride (CCl4)-induced liver fibrosis. The animals were received CCl4 or olive oil three times a week for 4 weeks. Histopathological analyses were performed to evaluate the fibrosis development in the mice. Alteration of protein expression controlled by Smad3 was examined using a proteomic analysis. CCl4-induced liver fibrosis was rarely detected in Smad3-/- mice compared to Smad3+/+. Proteomic analysis revealed that proteins related to antioxidant activities such as senescence marker protein-30 (SMP30), selenium-binding proteins (SP56) and glutathione S-transferases (GSTs) were up-regulated in Smad3-/- mice. Western blot analysis confirmed that SMP30 protein expression was increased in Smad3-/- mice. And SMP30 levels were decreased in CCl4-treated Smad3+/+ and Smad3-/- mice. These results indicate that Smad3 deficiency influences the proteins level related to antioxidant activities during early liver fibrosis. Thus, we suggest that Smad3 deteriorate hepatic injury by inhibitor of antioxidant proteins as well as mediator of TGF-β1 signaling.

Development and validation of a new histological score for pediatric non-alcoholic fatty liver disease

BACKGROUND & AIMS

Pediatric non-alcoholic fatty liver disease (NAFLD) may present with a distinct histopathological pattern characterized by the presence of predominant portal-based injury and portal inflammation (PI). We aimed at developing a new grading score for pediatric NAFLD to be used in clinical trials that takes into account the presence of PI and the weight of histological features.

METHODS

Our training set consisted of 203 children with biopsy-proven NAFLD. The diagnosis of non-alcoholic steatohepatitis (NASH) was based on Brunt's criteria. Histological features were scored: steatosis (0-3), lobular inflammation (0-3), ballooning (0-2), and PI (0-2). Logistic regression analysis was performed to apply weight to each feature. The new score was called the Pediatric NAFLD Histological Score or PNHS. The validation set consisted of 100 children with NAFLD.

RESULTS

The mean age of the initial cohort was 12.4 ± 3.4 years and significant fibrosis (fibrosis stage ≥ 2) was present in 26 patients (12.8%). NASH was diagnosed in 135 patients with a mean NAS of 4.5 ± 1.4. The mean PNHS in the NASH group was 89 ± 20.5 compared to 21.9 ± 24.5 in the "not NASH" group, p<0.001. PNHS correlated with the presence of NASH according to the pathologist's diagnosis, better than the NAFLD activity score (NAS), p=0.011. The area under the ROC curve (AUC) for the diagnosis of NASH was 0.96 for PNHS. Similar findings were observed in the validation set with an AUC of 0.94.

CONCLUSIONS

PNHS may be used for histological grading of pediatric NAFLD with excellent correlation with the presence of NASH.

The relevance of liver histology to predicting clinically meaningful outcomes in nonalcoholic steatohepatitis

Nonalcoholic fatty liver disease (NAFLD) has emerged as the most prevalent chronic liver disease. Nonalcoholic steatohepatitis (NASH), the more severe form of NAFLD, has an increased risk for progression to cirrhosis. The available data suggest increased morbidity and mortality among those patients with advanced histologic severity such as NASH and fibrosis. Despite the lack of a universally accepted histologic definition of NAFLD and inconsistency among pathologists regarding histologic findings essential to the diagnosis of NASH, a few studies have identified specific histologic findings (particularly fibrosis regardless of stage) that are able to predict NAFLD-related mortality as being most important.

Hepcidin expression in iron overload diseases is variably modulated by circulating factors

Hepcidin is a regulatory hormone that plays a major role in controlling body iron homeostasis. Circulating factors (holotransferrin, cytokines, erythroid regulators) might variably contribute to hepcidin modulation in different pathological conditions. There are few studies analysing the relationship between hepcidin transcript and related protein expression profiles in humans. Our aims were: a. to measure hepcidin expression at either hepatic, serum and urinary level in three paradigmatic iron overload conditions (hemochromatosis, thalassemia and dysmetabolic iron overload syndrome) and in controls; b. to measure mRNA hepcidin expression in two different hepatic cell lines (HepG2 and Huh-7) exposed to patients and controls sera to assess whether circulating factors could influence hepcidin transcription in different pathological conditions. Our findings suggest that hepcidin assays reflect hepatic hepcidin production, but also indicate that correlation is not ideal, likely due to methodological limits and to several post-trascriptional events. In vitro study showed that THAL sera down-regulated, HFE-HH and C-NAFLD sera up-regulated hepcidin synthesis. HAMP mRNA expression in Huh-7 cells exposed to sera form C-Donors, HFE-HH and THAL reproduced, at lower level, the results observed in HepG2, suggesting the important but not critical role of HFE in hepcidin regulation.

Correlations between histopathological diagnosis of chemotherapy-induced hepatic injury, clinical features, and perioperative morbidity

BACKGROUND

Chemotherapy has in some series been linked with increased morbidity after a hepatectomy. Hepatic injuries may result from the treatment with chemotherapy, but can also be secondary to co-morbid diseases. The aim of the present study was to draw correlations between clinical features, treatment with chemotherapy and injury phenotypes and assess the impact of each upon perioperative morbidity.

PATIENTS AND METHODS

Retrospective samples (n= 232) were scored grading steatosis, steatohepatitis and sinusoidal injury (SI). Clinical data were retrieved from medical records. Correlations were drawn between injury, clinical features and perioperative morbidity.

RESULTS

Injury rates were 18%, 4% and 19% for steatosis, steatohepatitis and SI, respectively. High-grade steatosis was more common in patients with diabetes [odds ratio (OR) = 3.33, P= 0.01] and patients with a higher weight (OR/kg = 1.04, P= 0.02). Steatohepatitis was increased with metabolic syndrome (OR = 5.88, P= 0.02). Chemotherapy overall demonstrated a trend towards an approximately doubled risk of high-grade steatosis and steatohepatitis although not affecting SI. However, pre-operative chemotherapy was associated with an increased SI (OR = 2.18, P= 0.05). Operative morbidity was not increased with chemotherapy, but was increased with steatosis (OR = 2.38, P= 0.02).

CONCLUSIONS

Diabetes and higher weight significantly increased the risk of steatosis, whereas metabolic syndrome significantly increased risk of steatohepatitis. The presence of high-grade steatosis increases perioperative morbidity, not administration of chemotherapy per se.

mRNA gene expression correlates with histologically diagnosed chemotherapy-induced hepatic injury

INTRODUCTION

Chemotherapy-induced hepatic injuries (CIHI) are an increasing problem facing hepatic surgeons. It may be possible to predict the risk of developing CIHI by analysis of genes involved in the metabolism of chemotherapeutics, previously established as associated with other forms of toxicity.

METHODS

Quantitative reverse transcriptase-polymerase chain reaction methodology (q-RT-PCR) was employed to quantify mRNA expression of nucleotide excision repair genes ERCC1 and ERCC2, relevant in the neutralization of damage induced by oxaliplatin, and genes encoding enzymes relevant to 5-flurouracil metabolism, [thymidylate synthase (TS), thymidine phosphorylase (TP) and dihydropyrimidine dehydrogenase (DPD)] in 233 hepatic resection samples. mRNA expression was correlated with a histopathological injury scored via previously validated methods in relation to steatosis, steatohepatitis and sinusoidal obstruction syndrome.

RESULTS

Low-level DPD mRNA expression was associated with steatosis [odds ratio (OR) = 3.95, 95% confidence interval (CI) = 1.53-10.19, P < 0.003], especially when stratified by just those patients exposed to chemotherapy (OR = 4.48, 95% CI = 1.31-15.30 P < 0.02). Low expression of ERCC2 was associated with sinusoidal injury (P < 0.001). There were no further associations between injury patterns and target genes investigated.

CONCLUSIONS

Predisposition to the development of CIHI may be predictable based upon individual patient expression of genes encoding enzymes related to the metabolism of chemotherapeutics.

Experimental induction of steatosis in different tissues after the ingestion of a carbohydrate-rich diet: effect on the liver, on the heart and on indicators of oxidation

CONTEXT

The western dietary pattern is characterized by a high calorie intake with a high proportion of simple sugars. This diet is associated with comorbidities such as hepatic fat deposition and is possibly related to non-alcoholic fatty liver disease.

OBJECTIVE

To evaluate the capacity of a hyperglucidic diet to induce steatosis in adult male Wistar rats. After the administration of a carbohydrate-rich diet, we also evaluated the presence of hepatic and cardiac steatosis and the levels of intrinsic antioxidants in the liver.

METHODS

Forty-six eutrophic adult male Wistar rats were used and 10 of them were chosen, at random, to serve as controls, while the remaining ones formed the experimental group. Control animals received the standard ration offered by the animal house and the experimental group received the hyperglucidic diet. The diets were offered for 21 days and, at the end of this period, tissue samples were collected for analysis of indicators of oxidative stress (malondialdehyde, and reduced glutathione) and of vitamin E. The animals were then sacrificed by decapitation and their viscera were removed for analysis of liver and heart fat.

RESULTS

The hyperglucidic diet used induced hepatic fat deposition, with lipid vacuoles being detected in 83% of the livers analyzed by histology. No lipid vacuoles were observed in the heart. Malondialdehyde and reduced glutathione levels remained unchanged when the animals were submitted to the hyperglucidic diet, probably because there was no liver development of fibrosis or inflammation. In contrast, the levels of vitamin E (antioxidant) were reduced, as confirmed in the literature for steatotic animals.

CONCLUSION

The hyperglucidic diet induced hepatic steatosis. In the heart there was an increase in fat content, although no histological changes were observed. These alterations cannot be explained by the presence of malondialdehyde or reduced glutathione (indicators of oxidation), since the values were similar in the groups studied. However, a significant reduction of vitamin E was observed in the experimental group.

The cytoskeleton in nonalcoholic steatohepatitis: 100 years old but still youthful

The hepatocellular cytoskeleton consists of three filamentous systems: microfilaments, microtubules and keratins (Ks). While the alterations in microfilaments and microtubules during nonalcoholic steatohepatitis (NASH) are largely unexplored, K8/K18 reorganization into Mallory-Denk bodies (MDBs) represents a NASH hallmark, and serological K18 fragments constitute an established tool to monitor NASH severity. To commemorate the 100th anniversary of the first description of MDBs, this article summarizes the composition and function of the hepatocellular cytoskeleton, as well as the importance of cytoskeletal alterations in NASH. The significance of MDBs in clinical routine is illustrated, as are the findings from MDB mouse models, which shape our current view of MDB pathogenesis. Even after 100 years, the cytoskeleton represents a fascinating but greatly understudied area of NASH biology.

Sophocarpine alleviates non-alcoholic steatohepatitis in rats

BACKGROUND AND AIM

Non-alcoholic steatohepatitis (NASH) is one entity in the spectrum of non-alcoholic fatty liver disease (NAFLD). The aim of this study was to explore the prevention and therapeutic effect of sophocarpine on experimental rat NASH.

METHODS

Sophocarpine with the dosage of 20 mg/kg/day was injected into NASH rats. At the end of 12 weeks, all rats were killed to detect the degree of fatty degeneration, inflammation and fibrosis.

RESULTS

Sophocarpine intervention (in the pro-treated and treated groups) resulted in a significant decrease of liver weight, liver index, serum transaminase and serum lipids. Messenger RNA expressions of leptin, interleukin (IL)-6, tumor necrosis factor (TNF)-α, transforming growth factor (TGF)-β1, procollagen-I and α-smooth muscle actin (SMA) and deposition of IL-6, TNF-α and TGF-β1 in liver decreased, whereas the messenger RNA expression of adiponectin increased significantly compared with that in the model group. Moreover, histological improvement was also observed in the sophocarpine intervention group. In addition, there was no significant difference in any detected indicator between the pro-treated and treated group.

CONCLUSIONS

Sophocarpine could decrease the level of serum transaminase, improve lipid metabolism, reduce synthesis of inflammatory cytokines TNF-α, TGF-β1 and IL-6, activate protective adipocytokine adiponectin, and might be selected as a promising agent for the clinical prevention and therapy of NASH.

Etiology-related determinants of liver stiffness values in chronic viral hepatitis B or C

BACKGROUND & AIMS

Transient elastography (TE) has gained popularity for the non-invasive assessment of severity of chronic viral hepatitis, but a comprehensive evaluation of the factors that might account for discrepancy in diagnostic accuracy between TE and the standard of care liver biopsy (LB) is still needed.

METHODS

Patients with chronic hepatitis-B (HBV, n=104) or -C (HCV, n=453) underwent percutaneous LB concomitantly with TE (FibroScan®; Echosens, Paris, France). Liver cell necroinflammatory activity (A) and fibrosis (F) were assessed by METAVIR. Perisinusoidal fibrosis was rated with a 0-3 score. Determinants of TE results were investigated by a linear regression model whereas discordance between TE and LB results was assessed by logistic regression.

RESULTS

Fibrosis (p<0.0001) and liver cell necroinflammatory activity (p<0.0001) were independently associated with TE results in both HBV and HCV patients, whereas steatosis (p<0.0001) was independently associated with TE in HCV only. Fibrosis overestimation was predicted by severe/moderate necroinflammatory activity in HBV and by older age (41-60 or>60years vs.<40), >2 UNL AST and>2 UNL GGT, as well as severe/moderate necroinflammatory activity and severe/moderate steatosis in HCV. In the latter patients, however, moderate/severe necroinflammatory activity and steatosis were the only independent predictors of fibrosis overestimation.

CONCLUSIONS

Fibrosis and necroinflammatory activity are the main determinants of TE in chronic viral hepatitis. Since TE staging of fibrosis is influenced by necroinflammatory activity and steatosis, a diagnostic LB is deemed necessary for a reliable intra-patient TE monitoring of the course of viral hepatitis.

Histopathological diagnosis of non-alcoholic and alcoholic fatty liver disease

The diagnostic procedures in patients with suspected fatty liver disease-with or without known alcohol consumption-should be standardized and generally accepted. We therefore present a guideline, summarizing the current concepts of etiology, diagnostic as well as differential diagnostic of patients with fatty liver disease. Alcoholic as well as and non-alcoholic fatty liver are characterised by lipid deposition in hepatocytes. The diagnosis of steatosis is made when lipid deposition exceeds 5% of hepatocytes, while involvement of more than 50% is called "fatty liver". An additional inflammatory reaction leads to alcoholic (ASH) or non-alcoholic steatohepatitis (NASH). Steatohepatitis is present when both inflammatory infiltrates of mixed cells in the small liver lobules as well as liver cell injury in terms of ballooning can be detected. Liver biopsy represents the "golden standard" for confirming diagnosis and determining inflammatory activity and potential fibrosis of fatty liver disease. The differential diagnosis of ASH vs. NASH cannot be made on the basis of histological criteria alone. Steatosis, inflammatory changes and hepatocytic injury can be semiquantified as a "Brunt Score" or "NAS" (NAFLD activity score), providing the basis on which to decide whether or not steatohepatitis is present. People at increased risk of developing a fatty liver possess an increased risk of developing chemotherapy-associated steatohepatitis. Histologically, pediatric NASH differs from adult NASH and is often only clinically manifest through a mild if persistent elevation in transaminases.

Histopathological diagnosis of non-alcoholic and alcoholic fatty liver disease

The diagnostic procedures in patients with suspected fatty liver disease-with or without known alcohol consumption-should be standardized and generally accepted. We therefore present a guideline, summarizing the current concepts of etiology, diagnostic as well as differential diagnostic of patients with fatty liver disease. Alcoholic as well as and non-alcoholic fatty liver are characterised by lipid deposition in hepatocytes. The diagnosis of steatosis is made when lipid deposition exceeds 5% of hepatocytes, while involvement of more than 50% is called "fatty liver". An additional inflammatory reaction leads to alcoholic (ASH) or non-alcoholic steatohepatitis (NASH). Steatohepatitis is present when both inflammatory infiltrates of mixed cells in the small liver lobules as well as liver cell injury in terms of ballooning can be detected. Liver biopsy represents the "golden standard" for confirming diagnosis and determining inflammatory activity and potential fibrosis of fatty liver disease. The differential diagnosis of ASH vs. NASH cannot be made on the basis of histological criteria alone. Steatosis, inflammatory changes and hepatocytic injury can be semiquantified as a "Brunt Score" or "NAS" (NAFLD activity score), providing the basis on which to decide whether or not steatohepatitis is present. People at increased risk of developing a fatty liver possess an increased risk of developing chemotherapy-associated steatohepatitis. Histologically, pediatric NASH differs from adult NASH and is often only clinically manifest through a mild if persistent elevation in transaminases.

Histopathological diagnosis of non-alcoholic and alcoholic fatty liver disease

The diagnostic procedures in patients with suspected fatty liver disease-with or without known alcohol consumption-should be standardized and generally accepted. We therefore present a guideline, summarizing the current concepts of etiology, diagnostic as well as differential diagnostic of patients with fatty liver disease. Alcoholic as well as and non-alcoholic fatty liver are characterised by lipid deposition in hepatocytes. The diagnosis of steatosis is made when lipid deposition exceeds 5% of hepatocytes, while involvement of more than 50% is called "fatty liver". An additional inflammatory reaction leads to alcoholic (ASH) or non-alcoholic steatohepatitis (NASH). Steatohepatitis is present when both inflammatory infiltrates of mixed cells in the small liver lobules as well as liver cell injury in terms of ballooning can be detected. Liver biopsy represents the "golden standard" for confirming diagnosis and determining inflammatory activity and potential fibrosis of fatty liver disease. The differential diagnosis of ASH vs. NASH cannot be made on the basis of histological criteria alone. Steatosis, inflammatory changes and hepatocytic injury can be semiquantified as a "Brunt Score" or "NAS" (NAFLD activity score), providing the basis on which to decide whether or not steatohepatitis is present. People at increased risk of developing a fatty liver possess an increased risk of developing chemotherapy-associated steatohepatitis. Histologically, pediatric NASH differs from adult NASH and is often only clinically manifest through a mild if persistent elevation in transaminases.

Histopathology of nonalcoholic fatty liver disease

Histological analysis of liver biopsies remains a standard against which other methods of assessment for the presence and amount of hepatic injury due to nonalcoholic fatty liver disease (NAFLD) are measured. Histological evaluation remains the sole method of distinguishing steatosis from advanced forms of NAFLD, i.e. nonalcoholic steatohepatitis (NASH) and fibrosis. Included in the lesions of NAFLD are steatosis, lobular and portal inflammation, hepatocyte injury in the forms of ballooning and apoptosis, and fibrosis. However, patterns of these lesions are as distinguishing as the lesions themselves. Liver injury in adults and children due to NAFLD may have different histological patterns. In this review, the rationale for liver biopsy, as well as the histopathological lesions, the microscopically observable patterns of injury, and the differential diagnoses of NAFLD and NASH are discussed.

[Histopathological diagnosis of non-alcoholic and alcoholic fatty liver disease. Grade 2 consensus-based guidelines]

Both alcoholic (AFL) and non-alcoholic fatty liver (NAFL) are characterized by lipid deposition in hepatocytes. The diagnosis of steatosis is made when lipid deposition exceeds 5% of hepatocytes, while involvement of more than 50% is called "fatty liver ". An additional inflammatory reaction leads to alcoholic (ASH) or non-alcoholic steatohepatitis (NASH). Steatohepatitis is present when both inflammatory infiltrates of mixed cells in the small liver lobules as well as liver cell injury in terms of ballooning can be detected.Liver biopsy represents the "gold standard" for confirming diagnosis and determining inflammatory activity and potential fibrosis of fatty liver disease.The differential diagnosis of ASH-NASH cannot be made on the basis of histological criteria alone. Steatosis, inflammatory changes and hepatocytic injury can be semiquantified as a "Brunt Score" or "NAS" (NAFLD activity score), providing the basis on which to decide whether or not steatohepatitis is present.People at increased risk of developing a fatty liver possess an increased risk of developing chemotherapy-associated steatohepatitis (CASH).Histologically, pediatric NASH differs from adult NASH and is often only clinically manifest through a mild if persistent elevation in transaminases.

Histopathological and ultrastructural studies on the effects of electromagnetic fields on the liver of preincubated white Leghorn chicken embryo

There are several reports indicating a linkage between exposures to 50-60 Hz electromagnetic fields and abnormalities in the early stages of embryonic development of chicken embryos. The present study was designed to demonstrate whether electromagnetic fields could be an environmental factor invoking histopathological and ultra-structural changes in livers of preincubated chicken embryos exposed to EMFs. Following other researchers and our previous results from different groups of Developmental Biology at the Animal Sciences, Faculty of Biological Sciences, Shahid-Beheshti University, effects of most effective intensities (1.33, 2.66, 5.52, and 7.32 mT) of electromagnetic fields (EMFs, 50 Hz ) on livers of pre-incubated white leghorn chicken embryos were investigated . 150 healthy, fresh, and fertilized eggs (55-65 gr) were divided into 6 groups of experimental(1-4, n = 30), control (n = 60), and sham (n = 50). Experimental eggs (inside coil) were exposed to 4 different intensities (1.33, 2.66, 5.52, and 7.32 mT). Sham groups were located inside same coil, with no exposure, for 24 h before incubation. Control, sham, and experimental groups (1-4) were then incubated in an incubator (38 +/- 0.5 degrees C, 60% humidity) for 17 days. At the end of this period, livers of experimental, sham, and control groups were processed for light and transmission electrom microscopes (TEM and SEM) studies. So, livers of 17-day old chicken embryos were removed by C-sections, fixed in formalin 10%, stained with H&E and reticulin, and studied under light microscope. Others were prepared for electron microscopes (TEM and SEM) investigations. Morphological observations indicated exencephalic embryos, embryos with asymmetrical faces, crossed beak, shorter upper beak, deformed hind limbs, gastroschesis, anophthalmia, and microphthalmia. H&E and reticulin stainings, TEMS, and SEMs studies indicated EMFs would create hepato-cytes with fibrotic bands, severe steatohepatitis, vacuolizations, swollen and extremely electron-dense mitochondria, reduced invisible cristae, crystalized mitochondria with degenerated cristae, myelin-like figures, macrophages engulfing adjacent cells, dentated nuclei, nuclei with irregular envelopes, degenerated hepatocytes, abnormal lipid accumulations, lipid droplets pushing hepatocytes' nuclei to the corner of the cells, abundant cellular infiltrations cellular infiltrations inside sinusoid and around central veins, disrupted reticulin plexus, and release of chromatin into cytosol,, with partially regular water layers. An elevated oxyradical generation and, subsequently, cell membrane disruptions were the reasons for electromagnetic fields inducing cell damages.

[Validity and reliability of the nonalcoholic fatty liver diseases activity score (NAS) in Korean NAFLD patients and its correlation with clinical factors]

BACKGROUND/AIMS

Nonalcoholic steatohepatitis (NASH) is commonly diagnosed using the semi-quantitative grading and staging system proposed by Brunt et al. in 1999. The Pathology Committee of the NASH established the nonalcoholic fatty liver diseases (NAFLD) activity score (NAS) in 2005. The aim of this study was to elucidate the validity and reliability of the NAS in Korean NAFLD patients.

METHODS

Fifty-six patients on whom sonography-guided liver biopsy for well-defined NAFLD was performed between 1999 and 2007 were identified retrospectively. Two pathologists evaluated each biopsy sample. NAFLD was evaluated using both the grading system developed by Brunt et al. and the NAS. Each pathologist was blinded to the patients' clinical data and scored independently. We evaluated the body mass index (BMI), liver enzymes, lipid profile, peripheral insulin resistance, leptin, insulin/c-peptide ratio, ferritin, and fasting blood glucose.

RESULTS

The patients were aged 32.1+/-12.5 years (mean+/-SD) and comprised 44 males (78.6%). Patients with different grades at the two grading systems had mild steatosis or ballooning changes with fibrosis, and 36.6% of them were borderline cases (NAS of 3 or 4). The interobserver agreement on diagnostic category was 0.748 (P<0.001) for the NAS (using weighted kappa statistics). Elevated fasting glucose, ALT, and triglyceride were associated with the NAS.

CONCLUSIONS

The simple and reproducible NAS was found to be a useful pathologic grading system in Korean NAFLD patients. However, the proportion of borderline cases based on the NAS was high. The "wait and see" strategy is necessary for evaluating the long-term prognosis.

Preventive effect of a melon extract rich in superoxide scavenging activity on abdominal and liver fat and adipokine imbalance in high-fat-fed hamsters

Studies showed that dietary antioxidants could be a therapy against obesity that is associated with a state of oxidative stress. Thus, this paper investigates whether a dietary ingredient, a melon juice extract rich in superoxide dismutase, would prevent the development of such obesity in hamsters. Five groups received a standard diet or a high-fat diet (HF) plus a daily gavage with water (control) or extract at 0.7, 2.8, or 5.6 mg/day. After 84 days, the higher dose lowered triglyceridemia (68%), production of liver superoxide anion (12%), mitochondrial cytochrome c oxidase activity (40%), lipid and protein oxidation products (35 and 35%, respectively), and leptinemia (99%) and increased adiponectinemia (29%), leading to a concomitant reduction in insulinemia (39%), insulin resistance (41%), and abdominal lipids (25%). The extract triggered a remarkable decrease of liver lipids (73%) and fully prevented the steatohepatitis induced by the HF diet. Chronic consumption of this melon extract may represent a new alternative to reduce obesity induced by a high-fat diet.

High fat diet induced hepatic steatosis establishes a permissive microenvironment for colorectal metastases and promotes primary dysplasia in a murine model

Non-alcoholic fatty liver disease (NAFLD), which includes steatosis and its progression to non-alcoholic steatohepatitis, is a liver disorder of increasing clinical significance. Here we characterize a murine model of high fat diet-induced NAFLD with progression from liver steatosis to histological features compatible with steatohepatitis and more advanced stages of NAFLD in humans, including chronic portal inflammation, pericellular and bridging fibrosis, Mallory body formation, and bile ductular reaction. Chronic changes induced by the prolonged consumption of a high-fat diet alone culminate in the development of primary liver dysplasias. Importantly, we extend these studies to demonstrate that even the early stages of uncomplicated steatosis provide a permissive microenvironment for the growth of colon cancer cells that are metastatic to the liver. High fat diet-induced steatosis, coupled with a splenic injection model of experimental liver metastasis using syngeneic MC38 colon cancer cells, resulted in an increased number of secondary tumor nodules and metastatic burden in steatotic livers. Metastatic nodules were associated with focal peritumoral areas of infiltrating inflammatory cells and associated apoptotic cell populations. These results suggest that the modulation of specific host factors in the steatotic liver contributes to tumor progression in the microenvironment of NAFLD.

Ballooned hepatocytes in steatohepatitis: the value of keratin immunohistochemistry for diagnosis

BACKGROUND/AIMS

Hepatocyte "ballooning" is an often used but ill defined term in liver pathology to designate a special form of liver cell degeneration associated with cell swelling and enlargement found particularly in steatohepatitis. Alterations of the intermediate filament cytoskeleton of the hepatocyte may contribute to the pathogenesis of this microscopic change. Ballooning degeneration is considered a hallmark of steatohepatitis, but enlarged hepatocytes may also be observed in a variety of other acute and chronic liver diseases.

METHODS

The intermediate filament cytoskeleton was investigated using keratin 8 and 18 immunohistochemistry in liver diseases associated with enlarged or ballooned hepatocytes.

RESULTS

Keratin 8/18 immunostaining was drastically reduced or lost in the cytoplasm of ballooned hepatocytes in alcoholic and non-alcoholic steatohepatitis, chronic cholestatic conditions, ischemia/reperfusion injury and in ballooned hepatocytes in chronic hepatitis C cases with concurrent steatohepatitis. In contrast, substantial decrease or loss of keratin 8/18 immunostaining was not noted in cases of acute hepatitis, giant cell hepatitis, chronic hepatitis B, or autoimmune hepatitis.

CONCLUSIONS

Loss of keratin 8/18 immunostaining can serve as an objective marker of a specific type of ballooning degeneration of hepatocytes. Oxidative stress may be a common denominator in the pathogenesis of keratin filament alterations in these conditions.

Intermediate filament cytoskeleton of the liver in health and disease

Intermediate filaments (IFs) represent the largest cytoskeletal gene family comprising approximately 70 genes expressed in tissue specific manner. In addition to scaffolding function, they form complex signaling platforms and interact with various kinases, adaptor, and apoptotic proteins. IFs are established cytoprotectants and IF variants are associated with >30 human diseases. Furthermore, IF-containing inclusion bodies are characteristic features of several neurodegenerative, muscular, and other disorders. Acidic (type I) and basic keratins (type II) build obligatory type I and type II heteropolymers and are expressed in epithelial cells. Adult hepatocytes contain K8 and K18 as their only cytoplasmic IF pair, whereas cholangiocytes express K7 and K19 in addition. K8/K18-deficient animals exhibit a marked susceptibility to various toxic agents and Fas-induced apoptosis. In humans, K8/K18 variants predispose to development of end-stage liver disease and acute liver failure (ALF). K8/K18 variants also associate with development of liver fibrosis in patients with chronic hepatitis C. Mallory-Denk bodies (MDBs) are protein aggregates consisting of ubiquitinated K8/K18, chaperones and sequestosome1/p62 (p62) as their major constituents. MDBs are found in various liver diseases including alcoholic and non-alcoholic steatohepatitis and can be formed in mice by feeding hepatotoxic substances griseofulvin and 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC). MDBs also arise in cell culture after transfection with K8/K18, ubiquitin, and p62. Major factors that determine MDB formation in vivo are the type of stress (with oxidative stress as a major player), the extent of stress-induced protein misfolding and resulting chaperone, proteasome and autophagy overload, keratin 8 excess, transglutaminase activation with transamidation of keratin 8 and p62 upregulation.

Pathological study of 130 cases of nonalcoholic fatty liver disease based on NASH-CRN system

To summarize the pathological features of nonalcoholic liver disease (NAFLD) in China based on a histological scoring system for NAFLD designed by the Pathology Committee of NASH Clinical Research Network (NASH-CRN), the specimens of liver needle biopsies from 130 patients with NAFLD were histopathologically analyzed by haematoxylin eosin, reticular fiber and Masson trichrome stain. Immunohistochemistry staining was used to exclude non-NAFLD cases combined with clinical data. Hepatic steatosis, lobular inflammation, hepatocytic ballooning and fibrosis were presented widespread in NAFLD liver tissues. Furthermore, macrovesicular steatosis predominantly located in acinar zone 3 was the main histologic feature of NAFLD and lobular inflammation was usually presented mildly. Hepatocyte ballooning was observed in 94.6% of all 130 cases. Mild perisinusoidal fibrosis and periportal fibrosis were often observed in stage 1 cases. According to the statistic analysis, hepatic steatosis was positively correlated with lobular inflammation, hepatocytic ballooning and fibrosis (r = 0.587, 0.488, 0.374, respectively, all P value < 0.01). The number of microgranulomas, lipogranulomas and apoptotic bodies increased following severity of steatosis, lobular inflammation and fibrosis. Meanwhile, the number of megamitochondria and glycogen nuclei was paralleveled to the degree of hepatocytic ballooning (P value all < 0.01). We suggest that the role of portal inflammation should be emphasized besides hepatic steatosis, lobular inflammation, hepatocyte ballooning and fibrosis in diagnosis and evaluation of NAFLD. It needs to be further verified whether microgranulomas, lipogranulomas and apoptosis bodies could be used as histopathological markers of development of NAFLD. The number of megamitochondria is more frequently be found in NAFLD, while in alcoholic liver diseases was Mallory bodies.

From Mallory to Mallory–Denk bodies: What, how and why?

Frank B. Mallory described cytoplasmic hyaline inclusions in hepatocytes of patients with alcoholic hepatitis in 1911. These inclusions became known as Mallory bodies (MBs) and have since been associated with a variety of other liver diseases including non-alcoholic fatty liver disease. Helmut Denk and colleagues described the first animal model of MBs in 1975 that involves feeding mice griseofulvin. Since then, mouse models have been instrumental in helping understand the pathogenesis of MBs. Given the tremendous contributions made by Denk to the field, we propose renaming MBs as Mallory-Denk bodies (MDBs). The major constituents of MDBs include keratins 8 and 18 (K8/18), ubiquitin, and p62. The relevant proteins and cellular processes that contribute to MDB formation and accumulation include the type of chronic stress, the extent of stress-induced protein misfolding and consequent proteasome overload, a K8-greater-than-K18 ratio, transamidation of K8 and other proteins, presence of p62 and autophagy. Although it remains unclear whether MDBs serve a bystander, protective or injury promoting function, they do serve an important role as histological and potential progression markers in several liver diseases.

Pathology of fatty liver disease

Fatty liver disease is currently recognized as a common cause of liver test elevation, paralleling the worldwide 'epidemic' of obesity in adults and children. In many clinical practices, there is recognition that liver biopsy evaluation is the only means of diagnosis (or exclusion) of fatty liver disease, as neither laboratory tests nor imaging studies to date can provide complete data related to amount of steatosis, inflammation, liver cell injury, fibrosis, and architectural remodeling. Liver biopsy evaluation also provides a means of 'grading and staging' the lesions of fatty liver disease and of detecting clinically unsuspected processes. Liver biopsy evaluation is often the primary end point in clinical trials of treatment, thus, standardization of diagnosis and methods of grading and staging have become important. In this review, these concepts as well as the pathophysiologic bases for them are discussed.

Histological assessment of non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is an important complication of the metabolic syndrome, which is becoming an increasingly common cause of chronic liver disease. Histological changes typically mainly affect perivenular regions of the liver parenchyma and include an overlapping spectrum of steatosis, steatohepatitis and persinusoidal or pericellular fibrosis, in some cases leading to cirrhosis. Once cirrhosis has developed, typical hepatocellular changes are often no longer conspicuous, leading to such cases being mistakenly diagnosed as 'cryptogenic'. Portal inflammation, ductular reaction and periportal fibrosis can also be seen as part of the morphological spectrum of NAFLD, particularly in the paediatric population. Hepatocellular carcinoma has also been described as a complication of NAFLD-associated cirrhosis. NAFLD is also an important cofactor in other chronic liver diseases, especially hepatitis C. Histological assessments have an important role to play in the diagnosis and management of NAFLD. These include making the potentially important distinction between simple steatosis and steatohepatitis and providing pointers to the aetiology, including cases where a dual pathology exists. A number of systems have been devised for grading and staging the severity of fatty liver disease. These require further evaluation, but have a potentially important role to play in determining prognosis and monitoring therapeutic responses.

Hepatobiliary pathology

PURPOSE OF REVIEW

Publications concerning liver histopathology in fatty liver disease and chronic hepatitis C, iron and copper overload, and liver transplantation from the past year have been surveyed to highlight useful concepts and diagnostic information.

RECENT FINDINGS

Two microscopic forms of pediatric nonalcoholic steatohepatitis have been described: type 1 in which hepatocyte ballooning and/or pericellular fibrosis accompany the steatosis; and type 2 which has portal tract inflammation and/or fibrosis as the salient accompanying feature. In chronic hepatitis C, the ductular reaction appears to be a major factor associated with fibrosis. In patients transplanted for hepatitis C virus-related cirrhosis, immunostaining of post-transplant liver biopsies for alpha-smooth muscle actin (i.e. in activated hepatic stellate cells) may identify those individuals at risk for severe recurrence. Clinicopathological papers on several forms of non-HFE hemochromatosis were published and Wilson's disease was described in individuals of 60 years or more in age. Cholestasis in childhood was expertly reviewed and histopathologic precursor lesions of hepatocellular carcinoma were also examined in a comprehensive article.

SUMMARY

Recent publications with impact on liver biopsy interpretation include a morphologic classification of nonalcoholic steatohepatitis in childhood, the differential diagnosis of childhood cholestasis and pathogenetic factors involved in fibrogenesis in chronic hepatitis C.

Nonalcoholic fatty liver disease: from steatosis to cirrhosis

Nonalcoholic steatohepatitis (NASH), the lynchpin between steatosis and cirrhosis in the spectrum of nonalcoholic fatty liver disorders (NAFLD), was barely recognized in 1981. NAFLD is now present in 17% to 33% of Americans, has a worldwide distribution, and parallels the frequency of central adiposity, obesity, insulin resistance, metabolic syndrome and type 2 diabetes. NASH could be present in one third of NAFLD cases. Age, activity of steatohepatitis, and established fibrosis predispose to cirrhosis, which has a 7- to 10-year liver-related mortality of 12% to 25%. Many cases of cryptogenic cirrhosis are likely endstage NASH. While endstage NAFLD currently accounts for 4% to 10% of liver transplants, this may soon rise. Pathogenic concepts for NAFLD/NASH must account for the strong links with overnutrition and underactivity, insulin resistance, and genetic factors. Lipotoxicity, oxidative stress, cytokines, and other proinflammatory mediators may each play a role in transition of steatosis to NASH. The present "gold standard" management of NASH is modest weight reduction, particularly correction of central obesity achieved by combining dietary measures with increased physical activity. Whether achieved by "lifestyle adjustment" or anti-obesity surgery, this improves insulin resistance and reverses steatosis, hepatocellular injury, inflammation, and fibrosis. The same potential for "unwinding" fibrotic NASH is indicated by studies of the peroxisome proliferation activator receptor (PPAR)-gamma agonist "glitazones," but these agents may improve liver disease at the expense of worsening obesity. Future challenges are to approach NAFLD as a preventive public health initiative and to motivate affected persons to adopt a healthier lifestyle.