Interaction of non-alcoholic fatty liver disease with other liver diseases

Increasing nonalcoholic steatohepatitis overlap in liver transplant recipients: Additive risk for de novo malignancy

BACKGROUND AND AIMS

Nonalcoholic steatohepatitis (NASH) is associated with metabolic conditions that increase the risk of de novo malignancy following transplant. Patients often have more than one underlying liver disease, which could change the risk of de novo malignancy. This study assessed the incidence of NASH overlap and its effect on de novo malignancy in liver transplant recipients.

METHODS

Data was analyzed from the United Network for Organ Sharing database for all liver transplant recipients from 1997 to 2017 for NASH alone or in combination with another liver disease.

RESULTS

There is an increasing prevalence of NASH overlap. Of the 98,679 patients included in the analysis, 1238 had a de novo malignancy identified (7.4% by 5 years post-transplant). The cumulative incidence of de novo malignancy increases in primary sclerosing cholangitis (PSC)/NASH overlap after 5 years and was increased in alcohol-related liver disease (ALD)/NASH through 10 years compared to ether disease alone. NASH overlaps with "other" diseases experience a cumulative incidence similar to NASH and not the "other" disease. An increased risk of de novo solid organ malignancy was associated with older age, male gender, previous malignancy, and multiorgan transplant.

CONCLUSION

The prevalence of liver transplant recipients with NASH overlap is increasing. These patients may experience different long-term outcomes than patients with either diagnosis alone. De novo malignancy risk can be influenced by multiple factors and metabolic comorbidities. Further study of patients with overlap diagnoses is important moving forward to guide individualized care and cancer screening programs.

Thalassemia and hepatocellular carcinoma: links and risks

The increased survival and lifespan of thalassemia patients, in the setting of better iron overload monitoring and chelation, have also however increased the incidence of diseases and complications, which were less likely to develop. Among these, one of the most worrying in recent years is hepatocellular carcinoma (HCC). Due to blood transfusions, many patients with thalassemia are or have been infected with hepatitis C virus (HCV) or hepatitis B virus (HBV), especially those born before the 1990s or in countries in which universal HBV vaccination and safe blood programs are still not completely implemented. However, HCC has also been described in nontransfused patients and in those who are HCV- and HBV-negative. Therefore, other risk factors are involved in hepatocarcinogenesis in thalassemia. The following review analyzes recent literature on the role of different risk factors in the progression of liver disease in thalassemia as well as the importance of surveillance. Treatment of HCC in thalassemia is still highly debated and requires further studies.

Nonalcoholic fatty liver disease (NAFLD): Diagnosis, pitfalls, and staging

Nonalcoholic fatty liver disease (NAFLD) is increasingly prevalent and strongly associated with obesity, diabetes and the metabolic syndrome, not only in the Western societies, but also in most regions of the world in the 21st century. The spectrum of its histopathology ranges from steatosis to nonalcoholic steatohepatitis (NASH), with risk for progressive fibrosis that may lead to cirrhosis and hepatocellular carcinoma (HCC). Benign and malignant liver tumors have also been more frequently reported with the increasing prevalence of obesity and diabetes. This review addresses the pathology of NAFLD and NASH, and their diagnostic features, diagnostic pitfalls, grading and staging, and clinical correlation.

Korean Patients Undergoing Deceased Donor Liver Transplantation for Alcoholic Liver Disease Have Non-Inferior Survival Outcomes than for Hepatitis B Virus: a Real-World Experience without Minimum Abstinence before Transplantation

Few studies have compared outcomes in patients undergoing liver transplantation (LT) for hepatitis B virus (HBV) and alcoholic liver disease (ALD) in Asian countries in which living donor LT (LDLT) is dominant, where HBV is endemic and where there are no strict regulations on pre-transplant abstinence for ALD. This study compared post-LT outcomes of deceased donor LT (DDLT) in patients with ALD and HBV. Data from 220 patients who underwent primary DDLT at Seoul National University Hospital from January 2010 to December 2014, including 107 with HBV and 38 with ALD, were retrospectively analyzed. Seventy-four patients (69.2%) in the HBV group and 30 (78.9%) in the ALD group had United Network for Organ Sharing (UNOS) status 2A (P = 0.250). There were no significant differences in their 1-year (90.7% vs. 92.1%) and 3-year (82.1% vs. 82.3%) overall survival rates (P = 1.000). Multivariate analysis showed that high serum gamma glutamyltransferase concentration (≥ 70 IU/L) was independently prognostic of 1-year post-LT overall survival. Survival outcomes following DDLT were similar in Korean patients with ALD and HBV, even in the absence of strict pre-transplant abstinence from alcohol as a selection criterion.

Analysis of the intrahepatic ductular reaction and progenitor cell responses in hepatitis C virus recurrence after liver transplantation

Fibrosis in livers with hepatitis C virus (HCV) recurrence after liver transplantation (LT) can be rapidly progressive, and the mechanisms underlying this process are poorly understood. In livers with HCV infections in the non-LT setting, there is a significant relationship between the development of structures known as the ductular reaction (DR), hepatic progenitor cells (HPCs), and fibrosis. This study characterizes the DR, HPCs, and fibrosis associated with HCV recurrence after LT. Immunohistochemistry and confocal microscopy were used to characterize the DR, HPC, and fibrosis in liver biopsy specimens. Key findings were confirmed in a separate, independent cohort. The initial characterization cohort had 194 biopsy samples from 105 individuals with HCV recurrence after LT. The immunophenotype, morphology, and location of the DR were consistent with an HPC origin. The DR correlated with intrahepatic fibrosis (rs  = 0.529, P < 0.001) and the number of activated hepatic stellate cells (HSCs; rs  = 0.446, P < 0.001). There was an early occurrence of hepatocyte replicative arrest as well as increased hepatocyte proliferation that correlated with the DR (rs  = 0.295, P < 0.001). Replicative arrest preceded hepatocyte proliferation in early-stage injury. Hepatocyte proliferation decreased with advanced fibrosis; in contrast, the extent of the DR and the number of activated HSCs continued to increase. In the second cohort of 37 individuals, the DR and the number of HPCs similarly correlated with fibrosis and inflammation after LT. In conclusion, this is the first characterization of the DR in HCV-associated liver injury after LT. There was a significant correlation between the DR and the development of progressive fibrosis in HCV recurrence. These results suggest a pivotal role for both the DR and the HPC responses in the aggressive fibrosis seen with HCV recurrence after LT.

Pathological features of fatty liver disease

Alcoholic liver disease (ALD) and nonalcoholic fatty liver disease (NAFLD) are significant causes of chronic liver disease worldwide. Both are characterized by histological lesions that can include steatosis, and each can lead to cirrhosis. It might be possible for pathologists to identify lesions and patterns of ALD and NAFLD; we review these lesions and propose methods to distinguish between the disorders. Any form of ALD can lead to end-stage liver disease, according to long-term studies of biopsy specimens and patient outcomes. Although steatosis can be a significant cofactor in progression of established chronic liver disease, or even development of hepatocellular carcinoma, only steatohepatitis indicates the presence of progressive liver disease in patients with NAFLD. Pediatric and adolescent NAFLD differ from adult nonalcoholic steatohepatitis and should be recognized as distinct conditions. Benign and malignant liver tumors have been more frequently reported with the increasing prevalence of obesity and diabetes. Histological scoring systems for ALD and NAFLD have been proposed to monitor efficacy in clinical trials and serve as prognostic factors. We review what we have learned from pathological analyses about the development of these disorders and how this information might be used to detect and treat them.

Pharmacological ceramide reduction alleviates alcohol-induced steatosis and hepatomegaly in adiponectin knockout mice

Hepatosteatosis, the ectopic accumulation of lipid in the liver, is one of the earliest clinical signs of alcoholic liver disease (ALD). Alcohol-dependent deregulation of liver ceramide levels as well as inhibition of AMP-activated protein kinase (AMPK) and peroxisome proliferator-activated receptor α (PPAR-α) activity are thought to contribute to hepatosteatosis development. Adiponectin can regulate lipid handling in the liver and has been shown to reduce ceramide levels and activate AMPK and PPAR-α. However, the mechanisms by which adiponectin prevents alcoholic hepatosteatosis remain incompletely characterized. To address this question, we assessed ALD progression in wild-type (WT) and adiponectin knockout (KO) mice fed an ethanol-containing liquid diet or isocaloric control diet. Adiponectin KO mice relative to WT had increased alcohol-induced hepatosteatosis and hepatomegaly, similar modest increases in serum alanine aminotransferase, and reduced liver TNF. Restoring circulating adiponectin levels using recombinant adiponectin ameliorated alcohol-induced hepatosteatosis and hepatomegaly in adiponectin KO mice. Alcohol-fed WT and adiponectin KO animals had equivalent reductions in AMPK protein and PPAR-α DNA binding activity compared with control-fed animals. No difference in P-AMPK/AMPK ratio was detected, suggesting that alcohol-dependent deregulation of AMPK and PPAR-α in the absence of adiponectin are not primary causes of the observed increase in hepatosteatosis in these animals. By contrast, alcohol treatment increased liver ceramide levels in adiponectin KO but not WT mice. Importantly, pharmacological inhibition of de novo ceramide synthesis in adiponectin KO mice abrogated alcohol-mediated increases in liver ceramides, steatosis, and hepatomegaly. These data suggest that adiponectin reduces alcohol-induced steatosis and hepatomegaly through regulation of liver ceramides, but its absence does not exacerbate alcohol-induced liver damage.

Precision-cut liver slices from diet-induced obese rats exposed to ethanol are susceptible to oxidative stress and increased fatty acid synthesis

Oxidative stress from fat accumulation in the liver has many deleterious effects. Many believe that there is a second hit that causes relatively benign fat accumulation to transform into liver failure. Therefore, we evaluated the effects of ethanol on ex vivo precision-cut liver slice cultures (PCLS) from rats fed a high-fat diet resulting in fatty liver. Age-matched male Sprague-Dawley rats were fed either high-fat (obese) (45% calories from fat, 4.73 kcal/g) or control diet for 13 mo. PCLS were prepared, incubated with 25 mM ethanol for 24, 48, and 72 h, harvested, and evaluated for ethanol metabolism, triglyceride production, oxidative stress, and cytokine expression. Ethanol metabolism and acetaldehyde production decreased in PCLS from obese rats compared with age-matched controls (AMC). Increased triglyceride and smooth muscle actin production was observed in PCLS from obese rats compared with AMC, which further increased following ethanol incubation. Lipid peroxidation, measured by thiobarbituric acid reactive substances assay, increased in response to ethanol, whereas GSH and heme oxygenase I levels were decreased. TNF-α and IL-6 levels were increased in the PCLS from obese rats and increased further with ethanol incubation. Diet-induced fatty liver increases the susceptibility of the liver to toxins such as ethanol, possibly by the increased oxidative stress and cytokine production. These findings support the concept that the development of fatty liver sensitizes the liver to the effects of ethanol and leads to the start of liver failure, necrosis, and eventually cirrhosis.

Inhibition of HCV replication by oxysterol-binding protein-related protein 4 (ORP4) through interaction with HCV NS5B and alteration of lipid droplet formation

Hepatitis C virus (HCV) RNA replication involves complex interactions among the 3’x RNA element within the HCV 3’ untranslated region, viral and host proteins. However, many of the host proteins remain unknown. In this study, we devised an RNA affinity chromatography /2D/MASS proteomics strategy and identified nine putative 3’ X-associated host proteins; among them is oxysterol-binding protein-related protein 4 (ORP4), a cytoplasmic receptor for oxysterols. We determined the relationship between ORP4 expression and HCV replication. A very low level of constitutive ORP4 expression was detected in hepatocytes. Ectopically expressed ORP4 was detected in the endoplasmic reticulum and inhibited luciferase reporter gene expression in HCV subgenomic replicon cells and HCV core expression in JFH-1-infected cells. Expression of ORP4S, an ORP4 variant that lacked the N-terminal pleckstrin-homology domain but contained the C-terminal oxysterol-binding domain also inhibited HCV replication, pointing to an important role of the oxysterol-binding domain in ORP4-mediated inhibition of HCV replication. ORP4 was found to associate with HCV NS5B and its expression led to inhibition of the NS5B activity. ORP4 expression had little effect on intracellular lipid synthesis and secretion, but it induced lipid droplet formation in the context of HCV replication. Taken together, these results demonstrate that ORP4 is a negative regulator of HCV replication, likely via interaction with HCV NS5B in the replication complex and regulation of intracellular lipid homeostasis. This work supports the important role of lipids and their metabolism in HCV replication and pathogenesis.

Liver steatosis correlates with iron overload but not with HFE gene mutations in chronic hepatitis C

BACKGROUND

Liver steatosis and iron overload, which are frequently observed in chronic hepatitis C (CHC), may contribute to the progression of liver injury. This study aimed to evaluate the correlation between liver steatosis and iron overload in Polish patients with CHC compared to non-alcoholic fatty liver disease (NAFLD) and HFE-hereditary hemochromatosis (HH) patients.

METHODS

A total of 191 CHC patients were compared with 67 NAFLD and 21 HH patients. Liver function tests, serum markers of iron metabolism, cholesterol and triglycerides were assayed. The inflammatory activity, fibrosis, iron deposits and steatosis stages were assessed in liver specimens. HFE gene polymorphisms were investigated by PCR-RFLP.

RESULTS

Liver steatosis was associated with obesity and diabetes mellitus. This disease was confirmed in 76/174 (44%) CHC patients, most of whom were infected with genotype 1. The average grade of steatosis was higher in NAFLD patients. CHC patients had significantly higher iron concentrations and transferrin saturations than NAFLD patients. Compared with CHC patients, HH patients had higher values of serum iron parameters and more intensive hepatocyte iron deposits without differences in the prevalence and intensity of liver steatosis. In the CHC group, lipids accumulation in hepatocytes was significantly associated with the presence of serum markers of iron overload. No correlation between the HFE gene polymorphism and liver steatosis in CHC patients was found.

CONCLUSIONS

Liver steatosis was diagnosed in nearly half of CHC patients, most of whom were infected with genotype 1. The intensity of steatosis was lower in CHC patients than that in NAFLD patients because of a less frequent diagnosis of metabolic syndrome. Only in CHC patients were biochemical markers of iron accumulation positively correlated with liver steatosis; these findings were independent of HFE gene mutations.

Chronic viral hepatitis: the histology report

In chronic viral hepatitis, the role of liver biopsy as a diagnostic test has seen a decline, paralleled by its increasing importance for prognostic purposes. Nowadays, the main indication for liver biopsy in chronic viral hepatitis is to assess the severity of the disease, in terms of both necro-inflammation (grade) and fibrosis (stage), which is important for prognosis and therapeutic management. Several scoring systems have been proposed for grading and staging chronic viral hepatitis and there is no a general consensus on the best system to be used in the daily practice. All scoring systems have their drawbacks and all may be affected by sampling and observer variability. Whatever the system used, a histological score is a reductive approach since damage in chronic viral hepatitis is a complex biological process. Thus, scoring systems are not intended to replace the detailed, descriptive, pathology report. In fact, lesions other than those scored for grading and staging may have clinical relevance and should be assessed and reported. This paper aims to provide a systematic approach to the interpretation of liver biopsies obtained in cases of chronic viral hepatitis, with the hope of helping general pathologists in their diagnostic practice.

Restriction of calorie and iron intake results in reduction of visceral fat and serum alanine aminotransferase and ferritin levels in patients with chronic liver disease

AIM

  To clarify the impact of visceral fat on chronic liver diseases such as non-alcoholic fatty liver disease (NAFLD) and hepatitis C, we investigated the effects of lifestyle modifications on the amount of visceral fat, liver biochemistry and serum ferritin levels in patients with liver disease.

METHODS

  Eighty-two patients (NAFLD, n = 37; hepatitis C, n = 45) were advised to adopt lifestyle modifications, including dietary changes and exercise, and these were maintained for 6 months. Bodyweight, percentage of body fat, visceral fat area (VFA) and serum alanine aminotransferase (ALT) and ferritin were measured before and after intervention.

RESULTS

  In NAFLD, the mean VFA of 134.5 cm(2) was significantly reduced to 125.3 cm(2) after 6 months (P < 0.001). ALT levels improved significantly between the values measured before and after intervention (P = 0.039). The VFA prior to intervention was 100 cm(2) in hepatitis C patients and it was reduced significantly after 6 months to 95.6 cm(2) (P < 0.001). ALT levels also improved significantly in the hepatitis C patients (P < 0.001). The serum ferritin levels also reduced in these patients. Improvements in serum ALT and ferritin levels correlated with the amount of visceral fat reduction in both groups (P = 0.046, P = 0.008, respectively).

CONCLUSION

  These findings demonstrate that restriction of calorie and iron intake results in reduction of visceral fat, liver enzymes and ferritin in patients with chronic liver disease. Visceral fat may be a central target for future interventions, not only in NAFLD but also in hepatitis C.

Steatosis as a co-factor in chronic liver diseases

The finding of lipid accumulation in the liver, so-called hepatic steatosis or non-alcoholic fatty liver disease, is a common condition frequently found in healthy subjects. Its prevalence, in fact, has been estimated by magnetic resonance studies to be about 35% in the general population and 75% in obese persons. Nevertheless, its presence generates liver damage only in a small percentage of subjects not affected by other liver diseases. It should be defined as a “co-factor” capable of affecting severity and progression, and also therapeutic perspectives, of liver diseases to which it is associated. Herein we will evaluate the impact of hepatic steatosis and obesity on the most common liver diseases: chronic viral hepatitis C and B, and alcoholic liver disease.

Liver biopsy in alcoholic and non-alcoholic steatohepatitis patients

Alcoholic liver disease and non-alcoholic liver disease share a similar histological spectrum that starts with 'simple' steatosis, and may be accompanied by inflammation. Alcoholic steatohepatitis and non-alcoholic steatohepatitis (NASH) are progressive forms of alcoholic liver disease and non-alcoholic liver disease, respectively, and can evolve into cirrhosis. The currently accepted minimum diagnostic criteria for steatohepatitis include steatosis, lobular inflammation and hepatocellular injury, but not fibrosis. Steatosis involving more than 5% of hepatocytes is required for the diagnosis of non-alcoholic fatty liver disease, but is not necessary for the diagnosis of alcoholic liver disease. Lobular inflammation is usually mild and frequently consists of a mixed, acute and chronic, inflammatory cell infiltrate composed of neutrophils and mononuclear cells. The presence of large numbers of neutrophils favors an alcoholic etiology. Hepatocellular injury in fatty liver disease usually occurs in the form of ballooning, but it can also present as apoptotic (acidophilic) bodies and lytic necrosis. The characteristic pattern of fibrosis in non-cirrhotic steatohepatitis is pericellular/perisinusoidal and is the result of deposition of collagen in the space of Disse. In both alcoholic steatohepatitis and NASH, sinusoidal collagen formation is the result of hepatic stellate cell activation that, in NASH, has been correlated with the grade of steatosis and fibrosis.

Clinical expression of insulin resistance in hepatitis C and B virus-related chronic hepatitis: differences and similarities

AIM

To investigate the prevalence of the clinical parameters of insulin resistance and diabetes in patients affected by chronic hepatitis C (CHC) or chronic hepatitis B (CHB).

METHODS

We retrospectively evaluated 852 consecutive patients (726 CHC and 126 CHB) who had undergone liver biopsy. We recorded age, sex, ALT, type 2 diabetes and/or metabolic syndrome (MS), body mass index (BMI), and apparent disease duration (ADD).

RESULTS

Age, ADD, BMI, prevalence of MS and diabetes in patients with mild/moderate liver fibrosis were significantly higher in CHC. However, the degree of steatosis and liver fibrosis evaluated in liver biopsies did not differ between CHC and CHB patients. At multivariate analysis, age, sex, BMI, ALT and diabetes were independent risk factors for liver fibrosis in CHC, whereas only age was related to liver fibrosis in CHB. We also evaluated the association between significant steatosis (>30%) and age, sex, BMI, diabetes, MS and liver fibrosis. Diabetes, BMI and liver fibrosis were associated with steatosis >30% in CHC, whereas only age and BMI were related to steatosis in CHB.

CONCLUSION

These data may indicate that hepatitis C virus infection is a risk factor for insulin resistance.

Diagnostic value of a computerized hepatorenal index for sonographic quantification of liver steatosis

OBJECTIVE

Quantification of liver steatosis is clinically relevant in various liver diseases but cannot be done by conventional sonography, which only provides a qualitative assessment with significant observer variability. The aim of this study was to assess sonography as an objective tool for the quantification of liver steatosis.

MATERIALS AND METHODS

Files of 111 patients with chronic liver disease who were referred for sonographically guided liver biopsy were collected. A hepatorenal sonographic index was calculated on the basis of the ratio between the echogenicity of the liver and that of the right kidney cortex using histogram echo intensity. Liver steatosis was graded by histology.

RESULTS

A significant correlation was found between histologic steatosis and the hepatorenal sonographic index (r = 0.82, p < 0.001). The validity of the hepatorenal sonographic index for the diagnosis of fatty liver was compared with liver biopsies with a steatosis level > 5%. The area under the receiver operating characteristic curve was 99.2% (95% CI, 98-100%). The optimal hepatorenal sonographic index cutoff point for the prediction of steatosis > 5% was 1.49, with sensitivity of 100% and specificity of 91%. The optimal hepatorenal sonographic index cutoff point for the prediction of steatosis >/= 25% was 1.86, with sensitivity of 90% and specificity of 90%. The optimal hepatorenal sonographic index cutoff point for the prediction of steatosis >/= 60% was 2.23, with sensitivity of 90% and specificity of 93%.

CONCLUSION

The hepatorenal sonographic index is a sensitive noninvasive method for steatosis quantification. It can diagnose small amounts of liver fat that would be missed by conventional sonography. It is reproducible and operator independent and can serve as an efficient tool to follow patients with steatosis and evaluate the efficacy of new treatment techniques.

Clinical expression of insulin resistance in hepatitis C and B virus-related chronic hepatitis: Differences and similarities

AIM: To investigate the prevalence of the clinical parameters of insulin resistance and diabetes in patients affected by chronic hepatitis C (CHC) or chronic hepatitis B (CHB).

METHODS: We retrospectively evaluated 852 consecutive patients (726 CHC and 126 CHB) who had undergone liver biopsy. We recorded age, sex, ALT, type 2 diabetes and/or metabolic syndrome (MS), body mass index (BMI), and apparent disease duration (ADD).

RESULTS: Age, ADD, BMI, prevalence of MS and diabetes in patients with mild/moderate liver fibrosis were significantly higher in CHC. However, the degree of steatosis and liver fibrosis evaluated in liver biopsies did not differ between CHC and CHB patients. At multivariate analysis, age, sex, BMI, ALT and diabetes were independent risk factors for liver fibrosis in CHC, whereas only age was related to liver fibrosis in CHB. We also evaluated the association between significant steatosis (> 30%) and age, sex, BMI, diabetes, MS and liver fibrosis. Diabetes, BMI and liver fibrosis were associated with steatosis > 30% in CHC, whereas only age and BMI were related to steatosis in CHB.

CONCLUSION: These data may indicate that hepatitis C virus infection is a risk factor for insulin resistance.

"Infectobesity: viral infections (especially with human adenovirus-36: Ad-36) may be a cause of obesity

In recent years viral infections have been recognized as possible cause of obesity, alongside the traditionally recognized causes (genetic inheritance, and behaviour/environmental causes such as diet exercise, cultural practices and stress). Although four viruses have been reported to induce obesity (infectoobesity) in animal models (chickens, mice, sheep, goat, dogs, rats and hamsters), until recently the viral etiology of human obesity has not received sufficient attention, possibly because the four viruses are not able to infect humans. In a series of papers over the last ten years, however, the group of Prof. Dhurandhar (Pennington Biomedical Research Center, LA, USA) demonstrated that a human adenovirus, adenovirus-36 (Ad-36), is capable of inducing adiposity in experimentally infected chickens, mice and non-human primates (marmosets). Ad-36 is known to increase the replication, differentiation, lipid accumulation and insulin sensitivity in fat cells and reduces those cells' leptin secretion and expression. It also affects human primary preadipocytes. In rats increased adiposity was observed due to Ad-36 infection. Recent studies have shown that, in the USA, antibodies to Ad-36 were more prevalent in obese subjects (30%) than in non-obese subjects (11%). We postulate that Ad-36 may be a contributing factor to the worldwide rising problem of obesity. We suggest the extension of comparative virological studies between North America and Europe, and studies between discordant twins (both dizygous and monozygous).

Nonalcoholic fatty liver disease: from clinical recognition to treatment

Nonalcoholic fatty liver disease (NAFLD) is probably the most common spectrum of metabolic liver disease in the world, encompassing simple steatosis to steatohepatitis, advanced fibrosis, cirrhosis and hepatocellular carcinoma. NAFLD affects a significant part of the general population worldwide. The existing correlation between obesity and NAFLD in combination with the increase in the frequency of obesity in the developed world implies that the incidence and severity of NAFLD will increase in the near future. Newer data support the idea that NAFLD constitutes the more important cause of cryptogenic cirrhosis of the liver and a ground for the development of hepatocellular carcinoma. Liver biopsy remains the most specific and sensitive method to differentiate NAFLD, providing important information on the long-term prognosis of the patients. The 'two hit' hypothesis constitutes the currently prevailing theory for the development of NAFLD and nonalcoholic steatohepatitis. The first 'hit' is purported to be the increase of free fatty acids in hepatocytes, which results in a decrease of beta-oxidation. The second step includes all mechanisms contributing to the development of necroinflammation and fibrosis. Currently, an effective treatment for patients with NAFLD does not exist. Improvement in liver histology remains the primary goal of any therapeutic approach in patients with NAFLD. Viewing NAFLD in the frame of the metabolic syndrome opens the possibility that both the onset of the disease and disease progression could be prevented by changes in lifestyle. Physical exercise and a low calorie diet in combination with the gradual loss of body weight represent the cornerstone for the management of NAFLD patients.

HCV core protein induces hepatic lipid accumulation by activating SREBP1 and PPARgamma

Hepatic steatosis is a common feature in patients with chronic hepatitis C virus (HCV) infection. HCV core protein plays an important role in the development of hepatic steatosis in HCV infection. Because SREBP1 (sterol regulatory element binding protein 1) and PPARgamma (peroxisome proliferators-activated receptor gamma) are involved in the regulation of lipid metabolism of hepatocyte, we sought to determine whether HCV core protein may impair the expression and activity of SREBP1 and PPARgamma. In this study, it was demonstrated that HCV core protein increases the gene expression of SREBP1 not only in Chang liver, Huh7, and HepG2 cells transiently transfected with HCV core protein expression plasmid, but also in Chang liver-core stable cells. Furthermore, HCV core protein enhanced the transcriptional activity of SREBP1. In addition, HCV core protein elevated PPARgamma transcriptional activity. However, HCV core protein had no effect on PPARgamma gene expression. Finally, we showed that HCV core protein stimulates the genes expression of lipogenic enzyme and fatty acid uptake associated protein. Therefore, our finding provides a new insight into the mechanism of hepatic steatosis by HCV infection.

Steatosis as a cofactor in other liver diseases: hepatitis C virus, alcohol, hemochromatosis, and others

As obesity prevalence rises, there is evidence that fatty liver disease can act synergistically with other chronic liver diseases to aggravate parenchymal injury. This is characterized best in chronic hepatitis C, where steatosis is caused by viral and metabolic effects. There is evidence that steatosis and its metabolic abnormalities also exacerbate other diseases, such as alcoholic liver disease, hemochromatosis, and, possibly, drug-induced liver disease. The pathogenesis seems related to increased susceptibility of steatotic hepatocytes to apoptosis, enhanced oxidative injury, and altered hepatocytic regeneration. Data suggest that active management of obesity may improve liver injury and decrease the progression of fibrosis in patients who have other chronic 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.

Impact of liver steatosis on the antiviral response in the hepatitis C virus-associated chronic hepatitis

BACKGROUND/AIM

Liver steatosis (LS) has been variably associated with chronic hepatitis C (CHC) but whether it affects sustained virological response to antiviral treatment and by what mechanisms is a question still under debate, at least for some genotypes. The aim of this work was to assess the frequency of LS, its relationship with host and viral factors and to what extent it can influence the response to antiviral combination therapy with pegylated interferon (INF)+ribavirin in a group of patients with CHC from a single center.

PATIENTS

One hundred and twelve patients with histologically proven CHC were treated with Peg INF-alpha 2a 180 microg a week subcutaneously for 48 weeks plus ribavirin 1000 or 1200 mg/day, according to the patient's body weight. Steatosis was graded according to Brunt et al.

RESULTS

Forty-six out of 112 patients (41.1%) were sustained virological responders (SVR). Seventy-two out of 112 (64.3%) presented with LS at histology; in this group, there were 24 patients (33.3%) with SVR compared with 22 (55%) of the non-steatosis group (chi(2)=6.5, P<0.02). Variables associated with the steatosis group were: higher serum levels of AST (P<0.04), alanine aminotransferase (P<0.02), gamma-GT (P<0.004), genotype 3a (P<0.03) and severity of histology (staging P<0.05) but at multiple linear regression analysis only genotype 3a and staging were significantly associated with LS. In the SVR group, age and body mass index (BMI) were significantly lower (P<0001 and P<0.03, respectively) compared with non-responders; moreover, genotype 1 was more frequent in the NR group, while genotype 3 was more frequent in the SVR group. At histology, grading and staging were also lower in the SVR group. Multiple logistic regression showed that only the grade of steatosis and genotype 3a were the variables independently associated with SVR.

CONCLUSIONS

This study showed a frequency of LS on the higher side of the range so far reported in the literature and confirmed that it negatively influences response to therapy. Genotype1 was confirmed to be the most frequent type in our area. It is more frequent in patients with mild-moderate steatosis and seems to condition therapeutic response negatively, together with BMI and age. In contrast, genotype 3a is more frequent in patients with severe steatosis, but is a favorable predictor of successful therapy.

Biliary wound healing, ductular reactions, and IL-6/gp130 signaling in the development of liver disease

Basic and translational wound healing research in the biliary tree lag significantly behind similar studies on the skin and gastrointestinal tract. This is at least partly attributable to lack of easy access to the biliary tract for study. But clinical relevance, more interest in biliary epithelial cell (BEC) pathophysiology, and widespread availability of BEC cultures are factors reversing this trend. In the extra-hepatic biliary tree, ineffectual wound healing, scarring and stricture development are pressing issues. In the smallest intra-hepatic bile ducts either impaired BEC proliferation or an exuberant response can contribute to liver disease. Chronic inflammation and persistent wound healing reactions in large and small bile ducts often lead to liver cancer. General concepts of wound healing as they apply to the biliary tract, importance of cellular processes dependent on IL-6/gp130/STAT3 signaling pathways, unanswered questions, and future directions are discussed.

The effect of the metabolic syndrome, hepatic steatosis and steatohepatitis on liver fibrosis in hereditary hemochromatosis

OBJECTIVES

The variability in phenotypic expression of hereditary hemochromatosis (HH) is not fully understood. We sought to examine whether the metabolic syndrome, hepatic steatosis or steatohepatitis influenced hepatic fibrosis among patients with HH and iron overload.

METHODS

We identified 86 patients with C282Y/C282Y or C282Y/H63D HH and iron overload (hepatic iron concentration (HIC) >2,200 microg/g for males, >1,600 microg/g for females). Features of the metabolic syndrome were assessed at the time of liver biopsy. Biopsies were scored by a blinded pathologist. Significant fibrosis was defined as peri-portal fibrosis or greater.

RESULTS

The mean (+/-SD) age of the study population was 53+/-12 years and 68 (79%) were male. The median (range) values of ferritin and HIC were 1,125 (253-9,530) microg/l and 9963 (1926-50 887) microg/g, respectively. The metabolic syndrome was present in 23 (27%), hepatic steatosis in 43 (50%), steatohepatitis in 18 (21%) and significant fibrosis in 38 (44%). Overall, neither the metabolic syndrome nor any of its components were associated with significant fibrosis or a higher mean fibrosis stage. Hepatic steatosis but not steatohepatitis was associated with a lower fibrosis stage. C282Y/H63D compound heterozygous individuals who had glucose intolerance had more severe fibrosis compared with those without glucose intolerance (1.0+/-1.0 vs. 0.1+/-0.3, P=0.01).

CONCLUSIONS

Overall, the metabolic syndrome and fatty liver were not associated with hepatic fibrosis among individuals with HH and iron overload. However, glucose intolerance may be important risk factor for the development of hepatic fibrosis in subjects with the C282Y/H63D HFE genotype.

Joint effects of body weight and alcohol on elevated serum alanine aminotransferase in the United States population

BACKGROUND & AIMS

Both alcohol and obesity are associated with hepatic steatosis. However, little is known about whether the toxicity of alcohol to the liver is influenced by adiposity. We examined the relationship of alcohol drinking and binge drinking with abnormal serum aminotransferase activity in normal weight, overweight, and obese persons in a national, population-based study.

METHODS

Data were analyzed from 13,580 adult participants in the third US National Health and Nutrition Examination Survey, 1988-1994, after excluding participants with hepatitis B or C or iron overload. Abnormal aminotransferase levels were defined by using sex-specific cutoffs for ALT and AST. Analyses were adjusted for other liver injury risk factors.

RESULTS

The prevalence of abnormal aminotransferase activity was elevated with consumption of >2 drinks per day or with overweight and obesity. In multivariate analysis, there was no association of alcohol intake with a higher prevalence of elevated aminotransferase levels among normal weight persons. In contrast, among overweight persons, consumption of >2 drinks per day increased the risk of elevated aminotransferase levels, and among the obese, > or = 1 drink per day was associated with a higher risk. Results were similar with elevated ALT alone as the outcome. With elevated AST alone as the outcome, intake of >2 drinks per day increased the risk, even among normal weight persons. Binge drinking was associated with aminotransferase elevation among obese consumers of 1-2 drinks per day.

CONCLUSIONS

In this large, national, population-based study, overweight and obesity increased the risk of alcohol-related abnormal aminotransferase activity.

Nonalcoholic steatohepatitis: pathologic features and differential diagnosis

The worldwide epidemic of obesity has raised the awareness of nonalcoholic fatty liver disease (NAFLD) from that of a curiosity to one of a potentially progressive liver disease with risk for cirrhosis and hepatocellular carcinoma. This overview is focused on the histopathology of the spectrum of fatty liver disease, and discusses the role of liver biopsy, differential diagnoses, and new techniques in development. When pertinent, pathophysiology of this metabolic liver disease and recent treatment considerations have been mentioned as well.

Steatosis: co-factor in other liver diseases

The prevalence of fatty liver is rising in association with the global increase in obesity and type 2 diabetes. In the past, simple steatosis was regarded as benign, but the presence of another liver disease may provide a synergistic combination of steatosis, cellular adaptation, and oxidative damage that aggravates liver injury. In this review, a major focus is on the role of steatosis as a co-factor in chronic hepatitis C (HCV), where the mechanisms promoting fibrosis and the effect of weight reduction in minimizing liver injury have been most widely studied. Steatosis, obesity, and associated metabolic factors may also modulate the response to alcohol- and drug-induced liver disease and may be risk factors for the development of hepatocellular cancer. The pathogenesis of injury in obesity-related fatty liver disease involves a number of pathways, which are currently under investigation. Enhanced oxidative stress, increased susceptibility to apoptosis, and a dysregulated response to cellular injury have been implicated, and other components of the metabolic syndrome such as hyperinsulinemia and hyperglycemia are likely to have a role. Fibrosis also may be increased as a by-product of altered hepatocyte regeneration and activation of bipotential hepatic progenitor cells. In conclusion, active management of obesity and a reduction in steatosis may improve liver injury and decrease the progression of fibrosis.

Role of liver biopsy in the assessment of non-alcoholic fatty liver disease

Assessments of liver biopsies are important in the diagnosis and management of non-alcoholic fatty liver disease. Histology remains the 'gold standard' for making the important distinction between simple steatosis, which is generally non-progressive and readily reversible, and steatohepatitis, which has the potential to progress to severe fibrosis or cirrhosis. Liver biopsy may also identify other causes of liver disease in patients thought to have fatty liver disease and vice versa. Histological grading and staging of fatty liver disease require further study but these are potentially important approaches for studying disease severity and progression, particularly in the context of clinical trials to assess novel therapeutic approaches.

Nonalcoholic steatohepatitis: histologic features and clinical correlations with 30 blinded biopsy specimens

Thirty overweight patients with clinically characterized and biopsy proven nonalcoholic steatohepatitis (NASH) were enrolled in a 48-week treatment trial with rosiglitazone, a peroxisome proliferator-activator receptor (PPAR)-gamma agonist that enhances insulin sensitivity. Improvement in laboratory liver tests, insulin resistance and liver fat content were documented; blinded biopsy review demonstrated decreases in necroinflammatory activity or grade and in individual components of grade, and changes in the relationship of lobular and portal inflammation as well as in the nature of perisinusoidal fibrosis. The current study identified correlations of histological features of the protocol entry biopsy specimens with contemporaneous laboratory and imaging tests. Significant correlations with histologically assessed steatosis were liver fat, evaluated by computed tomography (P = 0.001); mean HbA1C, a measure of glycemic control (P = 0.004); and QUICKI, a measure of insulin sensitivity (P = 0.05). Histologically determined grades of steatohepatitis (SH) correlated with HbA1C (P = 0.01), and a trend toward elevated fasting glucose levels was seen. No subject in the study was cirrhotic at entry; fibrosis scores of the 30 subjects did not significantly correlate with age, gender, body mass index, or clinical tests. All subjects underwent 3 biopsies (prior, entry, and posttreatment), and all had undergone a prior biopsy with diagnostic SH. By blinded analysis, 7 study entry biopsy specimens did not fulfill published strict criteria for SH. Laboratory results from these subjects included normal fasting glucose level and, compared with the 23 subjects with criteria for SH, lower mean alanine aminotransferase and aspartate aminotransferase levels (P = 0.02 for both), less insulin resistance (P = 0.03), and lower mean HbA1C (P = 0.001). We conclude that biopsy findings determined by blinded analysis correlated with image-detected steatosis, laboratory markers of hepatic inflammation, insulin resistance, and long-term glycemia; the findings confirm the usefulness of strict histological criteria in the evaluation of NASH.

The wide spectrum of steatohepatitis: a report of four cases and a review of the literature

We report on four cases displaying the wide range of aetiological risk factors (presence or absence of family history of dyslipidaemia and cryptogenic cirrhosis, from subnormal body mass index through morbid obesity, from absent through hepatotoxic alcohol consumption), laboratory test results (from subnormal through elevated uric acid and ferritin values), ultrasonographic changes (from normal findings through 'bright liver' with or without attenuation of ultrasound beam and absence/presence of focal lesions), and histological severity of steatohepatitis (fibrosis appearing to be inversely related to the amount of liver fat but zone 3 accentuation of lesions and ballooning being observed in all cases). Cases illustrate the concepts of overlapping aetiologies of steatohepatitis (hepatitis C, diabetes and lipodystrophy); the relationships between cryptogenic cirrhosis, familial cirrhosis, non-alcoholic fatty liver disease and hepatocellular carcinoma; familial hypobetalipoproteinaemia as an aetiology of steatohepatitis; and alcoholic liver disease in the obese. These issues, which are worthy of future investigation, are reviewed.

Nonalcoholic fatty liver disease: is all the fat bad?

Nonalcoholic fatty liver disease is now a major cause of liver disease in developed countries, largely as a result of an epidemic of obesity, diabetes and sedentary lifestyles. This has resulted in raised clinical awareness and diagnostic refinement. The entity encompasses several histologic patterns from benign steatosis to nonalcoholic steatohepatitis, the latter having a significant risk of progressive fibrosis and the development of cirrhosis. Laboratory tests and imaging are not able to distinguish steatosis from steatohepatitis, which requires liver biopsy. However following an assessment of several risk factors, patients can be stratified for the potential risk of fibrosis, allowing the rational use of liver biopsy. This review will describe the various patterns of nonalcoholic fatty liver disease and relate this to disease pathogenesis and progression. Strategies for management, including experimental interventions, will be discussed.

Risk factors for alcoholic liver disease in China

AIM: To examine the association of daily alcohol intake, types of alcoholic beverage consumed, drinking patterns and obesity with alcoholic liver disease in China.

METHODS: By random cluster sampling and a 3-year follow-up study, 1 270 alcohol drinkers were recruited from different occupations in the urban and suburban areas of Xi’an City. They were examined by specialists and inquired for information on: Medical history and family medical history, alcohol intake, types of alcoholic beverage consumed, drinking patterns by detailed dietary questionnaires. Routine blood tests and ultrasonography were done.

RESULTS: Multivariate analysis showed that: (1) The risk threshold for developing alcoholic liver disease was ingestion of more than 20 g alcohol per day, keeping on drinking for over 5 years in men. The highest OR was at the daily alcohol consumption > / = 160 g, the occurrence rate of ALD amounted to 18.7% (P < 0.01). No ALD occurred when ingestion of alcohol was less than 20 g per day. (2) 87.9% of all drank only at mealtimes. The cumulative risk of developing ALD was significantly higher in those individuals who regularly drank alcohol without food than in those who drank only at mealtimes, especially for those who regularly drank hard liquors only and multiple drinks (P < 0.05). (3) The alcohol consumption in those with BMI > / = 25 was lower than in those with BMI < 25, but the risk increased to 11.5%, significantly higher than that of general population, 6.5% (P < 0.01). (4) Abstinence and weight reduction could benefit the liver function recovery.

CONCLUSION: In the Chinese population the ethanol risk threshold for developing ALD is 20 g per day, and this risk increases with increased daily intake. Drinking 20 g of ethanol per day and for less than 5 years are safe from ALD. Drinking alcohol outside mealtimes and drinking hard liquors only and multiple different alcohol beverages both increase the risk of developing ALD. Obesity also increases the risk. Abstinence and weight reduction will directly affect the prognosis of ALD. Doctor’s strong advice might influence the prognosis indirectly.