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Original article
Portal inflammation is associated with advanced histological changes in alcoholic and non-alcoholic fatty liver disease
  1. Emad A Rakha1,
  2. Louise Adamson2,
  3. Emily Bell2,
  4. Keith Neal2,3,
  5. Stephen D Ryder2,
  6. Philip V Kaye1,2,
  7. Guruprasad P Aithal2
  1. 1Department of Pathology, Nottingham University Hospitals NHS Trust, Nottingham, UK
  2. 2Nottingham Digestive Diseases Centre, NIHR Biomedical Research Unit, Nottingham University Hospitals NHS Trust, Nottingham, UK
  3. 3Division of Epidemiology & Public Health, Nottingham University Hospitals NHS Trust, Nottingham, UK
  1. Correspondence to Dr Guruprasad P Aithal, Nottingham Digestive Diseases Centre, NIHR Biomedical Research Unit, D Floor, South Block, Queen's Medical Centre Campus, Derby Road, Nottingham NG7 2UH, UK; guru.aithal{at}nuh.nhs.uk

Abstract

Background Fatty liver disease (FLD), of either alcoholic (AFLD) or non-alcoholic (NAFLD) aetiologies, is characterised histologically by features that are lobulocentric that typically affect zone 3, in contrast with portal-based inflammation characteristics of other forms of chronic liver disease.

Aim The authors aimed to determine the prevalence and significance of portal inflammation in a cohort of adults diagnosed as having AFLD and NAFLD.

Methods From a histology database, the authors identified 160 patients with biopsy proven AFLD and 214 with NAFLD diagnosed between 1991 and 2001. All liver biopsies were reviewed by one pathologist to evaluate various histological features.

Results More than a mild degree of portal inflammation was found in 47% of AFLD compared with 30% in NAFLD subgroup. A higher degree of portal inflammation in AFLD was associated with a higher mean corpuscular volume, gamma glutamyl transferase (GGT) and alkaline phosphatase, and a lower platelet count and albumin, whereas in NAFLD this was associated with age, presence of diabetes, hypertension, body mass index (BMI), higher fasting blood glucose, cholesterol, alanine transaminase, GGT and ferritin. On regression analysis, portal inflammation was associated with the severity of steatosis (p=0.005), presence of ballooning (p=0.030) in NAFLD and severity of fibrosis in both AFLD and NAFLD (p<0.001).

Conclusions Portal inflammation is a common component of histological spectrum of both AFLD and NAFLD. In both conditions portal inflammation is associated with clinical and histological features suggestive of advanced disease.

  • Fatty liver disease
  • alcoholic
  • non-alcoholic
  • portal inflammation
  • inflammation
  • liver

https://doi.org/10.1136/jcp.2010.079145

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    Introduction

    Fatty liver disease (FLD) can be due to alcohol excess (AFLD) or non-alcoholic aetiology (NAFLD). The term NAFLD is used to describe the liver findings in patients with FLD in the absence of excess alcohol consumption.1 NAFLD is an important complication of the metabolic syndrome, including central obesity, insulin resistance, hypertension and hyperlipidaemia. NAFLD is now a common cause of chronic liver disease.2–4 As can be expected from their description, the histologies of AFLD and NAFLD are similar, and the distinction between the two is ultimately clinically derived.5 6 However, natural histories suggest that AFLD may progress more frequently than NAFLD.7 8

    Histologically, FLD is a spectrum, with the term steatohepatitis (SH) being used to define changes which indicate more severe and potentially progressive liver disease. Although the best definition of steatohepatitis remains unsettled, it can be defined as liver disease characterised by steatosis with evidence of liver cell injury (ballooning, necrosis and apoptosis) and inflammation with or without fibrosis mainly affecting zone 3.9–11 It is recognised that the histological changes in AFLD or NAFLD are lobulocentric (typically affecting zone 3), and they are sufficiently distinct from the portal-based lesions of chronic hepatitis such as viral and autoimmune hepatitis. Portal-based chronic inflammation in FLD, although relatively common, still remains an underappreciated lesion with debatable significance.12–14 The degree of portal inflammation was considered as one of the criteria of grading of non-alcoholic steatohepatitis (NASH) by the Brunt scoring system in 1999,11 13 but it was not included in the NASH Clinical Research Network (CRN) scoring system in 2005.15 Some authors have reported that portal inflammation in NAFLD, particularly if disproportionately high, may be an indication of the possibility of another, concurrent chronic ‘portal-based’ liver disease.16–18 In a recent study by the CRN group, Brunt et al14 concluded that more than mild portal inflammation in liver biopsies of untreated NAFLD may be considered a marker of advanced disease. Moreover, data on the significance of portal inflammation in AFLD are lacking.19 20 Therefore, the aims of this study are to determine the prevalence of portal inflammation as well as its clinical and histological correlates in a large series of adults with liver biopsy evidence of fatty liver disease of both alcoholic (AFLD) and non-alcoholic (NAFLD) aetiologies, in a single institution.

    Materials and methods

    Subjects and clinical data collection

    The pathology database at Queen's Medical Centre, Nottingham University was searched for cases coded as ‘fatty liver’ from January 1991 to December 2001. Using clinical information and laboratory tests, we excluded all those cases where drug therapy could have contributed to accumulation of fat (such as methotrexate, steroids, amiodarone, tetracycline, etc) as well as those associated with other specific liver diseases such as hepatitis B and C viral infection, haemochromatosis, auto-immune liver diseases, Wilson's disease, and alpha-1 antitrypsin deficiency. We identified adult subjects who were more than 18 years of age with biopsy-proven FLD. FLD was initially defined by the minimal criteria of hepatic steatosis (>5%) with or without lobular inflammation, Mallory–Denk bodies, cytological ballooning and fibrosis.1 9 21 22

    The following clinical data were collected:

    1. Patients characteristics including patient's age, gender, body weight and height (body mass index), presenting symptoms, past medication history, presence of diabetes, hypertension (including systolic and diastolic blood pressure), and the level of alcohol consumption (units per week) and its duration were also recorded.

    2. Results of liver chemistry (serum alanine transferase (ALT), alkaline phosphatase (ALP) and gamma-glutamyltransferase (GGT) in addition to serum bilirubin and albumin).

    3. Other blood tests including platelet counts, mean corpuscular volume (MCV), lipid profile (cholesterol level, low (LDL)/high-density lipoproteins (HDL) and triglycerides), C-reactive protein, ferritin level, creatinine, fasting blood glucose and glycated haemoglobin (haemoglobin A1c).

    4. Immunological markers including immunoglobulins IgA, IgG and IgM levels, and liver-disease-related autoantibodies (such as anti-nuclear, smooth muscle, liver kidney microsomal and antimitochondrial antibodies).

    Histopathology

    In our institution, sections of liver biopsies are routinely stained with haematoxylin–eosin, periodic acid Schiff, periodic acid Schiff-digested, reticulin, Picro-sirius red and/or Masson trichrome reagents, elastic tissue stain and iron stain. In the current study, all biopsies were reviewed by a hepatopathologist (PVK) without any knowledge of the clinical information. The length and width of the biopsies were recorded. The presence and severity of histological features were determined in a standardised way and scored semiquantitively from 0 to 4 as previously described by Promrat et al,23 and have been used in clinical trial.24 The scoring system was used for the entire spectrum of FLD without prior knowledge as to whether it was AFLD or NAFLD. These included ballooning degeneration of hepatocytes, parenchymal inflammation, portal inflammation, fibrosis and Mallory–Denk bodies.11 Portal inflammation was graded as 0 (none), 1 (mild, sprinkling of lymphocytes in some or all portal tracts), 2 (mild to moderate, denser lymphocytic infiltrate in some or most portal tracts), 3 (moderate to severe, dense lymphocytic infiltrate in most or all portal tracts) or 4 (severe, dense lymphocytic infiltrate in almost all or all portal tracts). Steatosis was graded as 1 (5–25%), 2 (26–50%), 3 (51–75%) and 4 (76–100%). Fibrosis was scored as 0 (no fibrosis), 1 (sinusoidal/pericellular), 2 (periportal), 3 (bridging) and 4 (diffuse).23 In addition, perisinusoidal/pericellular and portal fibrosis were assessed and scored separately as 0–4.25 The presence of oxyphilic change in hepatocytes, which is a form of cellular injury/degeneration due to accumulation of mitochondria frequently seen in severe alcoholic liver disease,26 was scored as absent or present. The degree and extent of fibrosis were evaluated on the trichrome stained slides according to the Kleiner system.15

    The degree of alcohol consumption as estimated at the time of presentation to the hospital was extracted from the case notes. If the subject consumed excess alcohol (units/week >14 for females, >21 for males) then it is considered alcoholic fatty liver disease, whereas those who consumed less than that amount of alcohol were classified as non-alcoholic fatty liver disease.11 27 In this study, FLD which scored positively for cellular injury (ballooning/oncocytic/oxyphilic change/necrosis) and/or fibrosis was regarded as steatohepatitis.

    Data analysis

    Statistical analysis was performed using SPSS 15.0 statistical software (SPSS, Chicago, Illinois). The means, standard deviations, medians, ranges and percentages were reported for various demographic and clinical features. In characterising the relationships between portal inflammation and clinical and histopathological features, the Spearman rank correlation, χ2 test and Mann–Whitney U test were used. To identify relationships between the severity of portal inflammation and laboratory/histological features, the Student t test, linear regression and the Welch test for unequal variances were used. The associations between portal inflammation and other clinicopathological variables were analysed using the degree of portal inflammation scored as five categories (0–4) as well as when dichotomised (as absent (0) or mild (1) versus more than mild (2–4)).14 20 A p value <0.05 was considered significant. However, with multiple statistical comparisons, a p value <0.01 was considered significant.

    Results

    Demographic and clinical features

    Out of 418 liver biopsies coded as fatty liver, 374 cases that met the criteria for inclusion in this study were included (adults with fatty liver without other concomitant chronic liver disease). Fourteen cases were further excluded due to absent or insufficient biopsy material, and therefore, 360 cases (263 males, 97 females) were included in the final analysis. These included 154 (43%) patients with AFLD and 206 (57%) with NAFLD. The median age of patients was 49 years (range: 20–80). The most frequent presentation was abnormal liver function tests with or without other symptoms. Pain was the presenting symptom in 33 (9%) patients. The median length of biopsies was 19.5 mm (range 5–70), and the median width was 1 mm (range 0.4–1.5); 296 (82%) were regarded as steatohepatitis (SH), while 64 cases did not show any evidence of parenchymal injury or fibrosis

    Characteristics of AFLD and NAFLD

    The clinical and histological characteristics of the whole cohort and the difference between AFLD and NAFLD subgroups are detailed in tables 1 and 2. AFLD patients were more likely to be male but less likely to be diabetic than patients with NAFLD. Patients with AFLD more often presented with abnormal liver function tests (elevated GGT, ALP and total bilirubin and reduced albumin), lower platelet count, higher ferritin and IgA levels when compared with NAFLD patients.

    View this table:
    Table 1

    Clinical characteristics of patients with fatty liver disease including alcoholic and non-alcoholic aetiology

    View this table:
    Table 2

    Histopathological characteristics of patients with steatohepatitis

    All histological features of FLD apart from steatosis itself were significantly more severe in the AFLD group, and the stage was also more advanced in this group. More than a mild degree of portal inflammation was found in 47% of AFLD compared with 30% in NAFLD subgroup (p=0.001). Regression analysis showed that fibrosis stage is the most significant histological feature associated with AFLD subgroup (p<0.001) followed by oxyphilic changes (p=0.028).

    Correlation between portal inflammation and other clinicopathological variables

    NAFLD subgroup

    Patients with more than mild portal inflammation were older, more likely to be diabetic and more likely to have high ALT and ferritin levels and LDL levels. There was no association between portal inflammation and levels of albumin, alkaline phosphatase and immunoglobulins, or autoantibody positivity (table 3).

    View this table:
    Table 3

    Correlation between portal inflammation and clinical characteristics of patients with alcoholic fatty liver disease or non-alcoholic fatty liver disease groups (p values)

    An increasing degree of portal inflammation was associated with other features which indicate the severity of the disease including advanced grade of steatosis, lobular inflammation, liver cell injury (ballooning degeneration) and the presence and extent of fibrosis including pericellular and portal fibrosis (p<0.001) and the presence of SH (table 4). Regression analysis showed an association between portal inflammation and severity of fibrosis (p<0.001), degree of steatosis (p=0.005) and the presence of ballooning degeneration (p=0.030) while lobular inflammation, Mallory hyaline and iron deposition were not significant (p>0.05).

    View this table:
    Table 4

    Correlation between portal inflammation* and histopathological characteristics in both alcoholic steatohepatitis and non-alcoholic steatohepatitis groups

    AFLD subgroup

    More than mild portal inflammation was more frequently associated with high alkaline phosphatase and ferritin, and low albumin and high-density lipoprotein levels. Similar to the NAFLD subgroup, there were associations between increasing degree of portal inflammation and other features which indicate the severity of the disease including advanced stage of lobular inflammation, ballooning degeneration, steatosis, oxyphilic changes, fibrosis, including portal fibrosis (p<0.001) and the presence of SH (table 4). Regression analysis showed an association between portal inflammation and severity of fibrosis (p<0.001) while other histological features were not significant (p>0.05).

    Similar associations were found when portal inflammation was analysed as categories (0–4) in both NAFLD and AFLD. There was a correlation between the length of the biopsy and portal inflammation in NAFLD (p<0.001) but not in AFLD (p=0.21). Similar correlations were also found between the length of the biopsy and both lobular inflammation and fibrosis but not with other variables. No association was found between immunoglobulins (IgA, IgG or IgM) or autoantibody positivity and other histological findings apart from association between IgA and degree of steatosis and stage of fibrosis in NAFLD (p<0.001). Autoantibody positivity was associated with female sex (χ2=7.3, p=0.007) in the whole series. However, when analysed separately, this association with female sex was found in NAFLD (χ2=9.2, p=0.002) but not in the AFLD subgroup (χ2=0.01, p=0.983).

    Discussion

    The histological spectrum of FLD includes steatosis, hepatocellular injury (ballooning degeneration, apoptosis or Mallory bodies), inflammation and fibrosis of varying degree. As AFLD and NAFLD share a similar histological spectrum, the distinction between the two conditions remains clinically based, almost entirely on a history of alcohol intake. Key characteristic histological features in AFLD and NAFLD have been noted in centrilobular location which may be consistent with the metabolic zonation within the liver acinus,28 and periportal changes have received relatively less attention. Our study shows that portal inflammation is seen in the majority of subjects with AFLD (71%) as well as NAFLD (63%). Our findings are consistent with two recent studies; one found portal inflammation in 83% of 728 adults and 90% of 205 children with NAFLD,14 and another found portal inflammation in 40% of 200 adults AFLD.20

    In NAFLD, portal inflammation has previously been noted in certain clinical settings such as in children,29 those with concurrent chronic liver disease30 or following treatment of NAFLD especially with glitazones.31 Portal-based pathology has also been described as distinct pathological entities in paediatric subjects such as type 2 NASH without ballooning and perisinusoidal changes29 and isolated portal fibrosis seen in morbidly obese subjects.32 Our cohort included well-characterised patients with FLD from which other causes of chronic liver disease and drug-induced fatty liver disease had been excluded; hence, our findings confirm with another recent retrospective series33 that portal inflammation is a common component of histological spectrum of both AFLD and NAFLD.

    In patients with NAFLD, more than mild portal inflammation correlated with several clinical parameters such as age, diabetes, hypertension, BMI as well as laboratory parameters such as fasting blood glucose, ALT, total cholesterol, LDL and ferritin levels. Previous reports have described the association between advanced histological changes such as fibrosis in NAFLD and many of these clinical parameters such as age, BMI,34–36 presence of diabetes,34 35 37 hypertension,37 ALT and triglyceride levels36 in different cohorts of NAFLD patients. Our findings are also in agreement with a recent report from the USA,14 which found more than mild portal inflammation to be associated with age, female gender, BMI, diabetes and hypertension, although, unlike our study, no association between portal inflammation and ALT levels was found. In contrast to NAFLD, none of the factors such as age, presence of diabetes, obesity and hypertension was associated with more than mild portal inflammation in AFLD cases. Instead, in AFLD, lower albumin levels, lower platelet counts, higher MCV and ferritin levels were associated with significant portal inflammation. All these factors are surrogate markers of advanced AFLD; hence similar to NAFLD more than mild portal inflammation in AFLD implies advanced histological changes. However, although we found ferritin levels to be associated with portal inflammation in both AFLD and NAFLD, there are conflicting reports regarding association of hepatic fibrosis with serum ferritin levels in NAFLD with data both confirming38 and denying the association.39

    In this study, portal inflammation was associated with features of advanced histological changes including the extent of steatosis, presence and extent of lobular inflammation, liver cell injury, fibrosis and the presence of SH. However, we cannot confirm whether portal inflammation is simply a marker of severity in AFLD/NAFLD or contributes to pathogenesis of this progressive disease. Previous studies have suggested that small intestinal bacterial overgrowth, intestinal permeability and gut-derived endotoxaemia may play a role in the pathogenesis of AFLD40 and NAFLD.41 42 Consistent with such a hypothesis, we found that raised IgA levels were associated with the higher degree of steatosis and stage of fibrosis (p<0.001). Alternatively, it can be hypothesised that activation of the innate immune system and increased release of pro-inflammatory cytokines from portal tract inflammatory cells may lead to perpetuation of inflammation, hepatocyte damage and hence advanced disease in both AFLD and NAFLD.43–45 In our study, autoantibody positivity was strongly associated with female gender in the NAFLD cohort, thus supporting the view that activation of immune system may contribute in pathogenesis. However, there was no association between portal inflammation and autoantibodies or immunoglobulins in AFLD or NAFLD as a group. A previous study investigating the determinants of progressive fibrosis in NAFLD showed that portal inflammation was independently and strongly (odds ratio of 3) associated with fibrosis.12 These authors hypothesised that as the primary pathway of replacement of necrotic and apoptotic hepatocytes through replication of adjacent hepatocytes is impaired in NAFLD, a secondary proliferative pathway, the so-called ‘ductular reaction’, is activated, hence explaining the association of portal inflammation with progressive fibrosis.12 A similar association between portal inflammation and fibrosis has also been reported in AFLD.20 In a recent study, Argo et al46 identified portal inflammation as a predictor of fibrosis progression as well as a marker of disease severity in NAFLD. However, only long-term natural history studies including a large cohort of subjects with repeat biopsies at follow-up will be able to confirm the significance of portal inflammation in NAFLD.

    Overall, in our study, AFLD patients as a group had more advanced histological features compared with those with NAFLD at the time of biopsy. Both frequency and degree of inflammation (lobular and portal), evidence of hepatocellur injury (ballooning and Mallory–Denk bodies) and fibrosis (presence/extent of pericellular fibrosis and the overall fibrosis stage) were significantly higher in the AFLD group. Consistent with these, AFLD group had clinical evidence of more advanced disease as shown by higher bilirubin, lower albumin and lower platelet counts, despite the fact that there was no difference in the mean age between the two groups. Although AFLD and NAFLD both have a similar histological spectrum and hence are inseparable based on histopathology alone, the two conditions have a different natural history. This was demonstrated by two landmark studies of natural history of fatty liver.7 8 In these studies, two retrospective cohorts of pure fatty liver were followed up for a period of 10 years. While 2.5% (1/40) of NAFLD developed mild fibrosis on follow-up biopsy,7 18% of those with AFLD developed fibrosis; including 10% with cirrhosis.8 This points to a more rapid progression of AFLD when compared with NAFLD under the circumstances where there is persistent exposure to risk factors. Therefore, it is unsurprising that the cohort with AFLD have more advanced liver disease compared with the NAFLD cohort. We acknowledge that our study design has some inherent limitations. Patients forming these cohorts were identified from the liver biopsy database, and biopsies were performed based on clinical indications rather than any predetermined criteria. Therefore, the threshold for biopsy may have varied depending on clinical circumstances and the clinicians requesting liver biopsy. It is often difficult to draw a line between AFLD and NAFLD. Alcoholic history may be difficult to obtain and quantify. Alcohol consumption may coexist with factors of metabolic syndrome.

    We conclude that portal inflammation is a common component of the histological spectrum of both AFLD and NAFLD. In both conditions, portal inflammation is associated with clinical and histological features suggestive of advanced disease.

    Take-home messages

    • Alcoholic (AFLD) and non-alcoholic (NAFLD) fatty liver disease share a similar histological spectrum, and the distinction between the two conditions remains clinically based.

    • Histological features of advanced liver disease such as hepatocellular injury, inflammation and fibrosis were significantly more severe in AFLD than in NAFLD.

    • Although the key characteristic histological features in AFLD and NAFLD have been noted in centrilobular location, this study demonstrates that portal inflammation is a common component of the histological spectrum of both AFLD and NAFLD.

    • More than mild degree of portal inflammation is found in approximately half of AFLD compared with a third in NAFLD subgroup.

    • In both conditions, portal inflammation is associated with clinical and histological features suggestive of advanced disease including severity of fibrosis.

    • No significant association is found between level of immunoglobulins or autoantibody positivity and histological findings in FLD.

    References

    1. ↵
      1. Ludwig J,
      2. Viggiano TR,
      3. McGill DB,
      4. et al
      . Nonalcoholic steatohepatitis: Mayo Clinic experiences with a hitherto unnamed disease. Mayo Clin Proc 1980;55:434–8.
      OpenUrlCrossRefPubMedWeb of Science
    2. ↵
      1. Kumar KS,
      2. Malet PF
      . Nonalcoholic steatohepatitis. Mayo Clin Proc 2000;75:733–9.
      OpenUrlCrossRefPubMedWeb of Science
    3. ↵
      1. James O,
      2. Day C
      . Non-alcoholic steatohepatitis: another disease of affluence. Lancet 1999;353:1634–6.
      OpenUrlCrossRefPubMedWeb of Science
    4. ↵
      1. Wanless IR,
      2. Lentz JS
      . Fatty liver hepatitis (steatohepatitis) and obesity: an autopsy study with analysis of risk factors. Hepatology 1990;12:1106–10.
      OpenUrlCrossRefPubMedWeb of Science
    5. ↵
      1. Brunt EM
      . Alcoholic and nonalcoholic steatohepatitis. Clin Liver Dis 2002;6:399–420.
      OpenUrlCrossRefPubMed
    6. ↵
      1. Diehl AM,
      2. Goodman Z,
      3. Ishak KG
      . Alcohol like liver disease in nonalcoholics. A clinical and histologic comparison with alcohol-induced liver injury. Gastroenterology 1988;95:1056–62.
      OpenUrlPubMedWeb of Science
    7. ↵
      1. Teli MR,
      2. James OF,
      3. Burt AD,
      4. et al
      . The natural history of nonalcoholic fatty liver: a follow-up study. Hepatology 1995;22:1714–19.
      OpenUrlCrossRefPubMedWeb of Science
    8. ↵
      1. Teli MR,
      2. Day CP,
      3. Burt AD,
      4. et al
      . Determinants of progression to cirrhosis or fibrosis in pure alcoholic fatty liver. Lancet 1995;346:987–90.
      OpenUrlCrossRefPubMedWeb of Science
    9. ↵
      1. Brunt EM
      . Nonalcoholic steatohepatitis (NASH): further expansion of this clinical entity? Liver 1999;19:263–4.
      OpenUrlPubMedWeb of Science
    10. ↵
      1. Brunt EM
      . Nonalcoholic steatohepatitis: definition and pathology. Semin Liver Dis 2001;21:3–16.
      OpenUrlCrossRefPubMedWeb of Science
    11. ↵
      1. Neuschwander-Tetri BA,
      2. Caldwell SH
      . Nonalcoholic steatohepatitis: summary of an AASLD Single Topic Conference. Hepatology 2003;37:1202–19.
      OpenUrlCrossRefPubMedWeb of Science
    12. ↵
      1. Richardson MM,
      2. Jonsson JR,
      3. Powell EE,
      4. et al
      . Progressive fibrosis in nonalcoholic steatohepatitis: association with altered regeneration and a ductular reaction. Gastroenterology 2007;133:80–90.
      OpenUrlCrossRefPubMedWeb of Science
    13. ↵
      1. Brunt EM,
      2. Janney CG,
      3. Di Bisceglie AM,
      4. et al
      . Nonalcoholic steatohepatitis: a proposal for grading and staging the histological lesions. Am J Gastroenterol 1999;94:2467–74.
      OpenUrlCrossRefPubMedWeb of Science
    14. ↵
      1. Brunt EM,
      2. Kleiner DE,
      3. Wilson LA,
      4. et al
      . Portal chronic inflammation in nonalcoholic fatty liver disease (NAFLD): a histologic marker of advanced NAFLD-Clinicopathologic correlations from the nonalcoholic steatohepatitis clinical research network. Hepatology 2009;49:809–20.
      OpenUrlCrossRefPubMedWeb of Science
    15. ↵
      1. Kleiner DE,
      2. Brunt EM,
      3. Van Natta M,
      4. et al
      . Design and validation of a histological scoring system for nonalcoholic fatty liver disease. Hepatology 2005;41:1313–21.
      OpenUrlCrossRefPubMedWeb of Science
    16. ↵
      1. Brunt EM,
      2. Ramrakhiani S,
      3. Cordes BG,
      4. et al
      . Concurrence of histologic features of steatohepatitis with other forms of chronic liver disease. Mod Pathol 2003;16:49–56.
      OpenUrlCrossRefPubMedWeb of Science
    17. ↵
      1. Sanyal AJ,
      2. Contos MJ,
      3. Sterling RK,
      4. et al
      . Nonalcoholic fatty liver disease in patients with hepatitis C is associated with features of the metabolic syndrome. Am J Gastroenterol 2003;98:2064–71.
      OpenUrlCrossRefPubMedWeb of Science
    18. ↵
      1. Hubscher SG
      . Histological assessment of non-alcoholic fatty liver disease. Histopathology 2006;49:450–65.
      OpenUrlCrossRefPubMedWeb of Science
    19. ↵
      1. Yip WW,
      2. Burt AD
      . Alcoholic liver disease. Semin Diagn Pathol 2006;23:149–60.
      OpenUrlCrossRefPubMed
    20. ↵
      1. Colombat M,
      2. Charlotte F,
      3. Ratziu V,
      4. et al
      . Portal lymphocytic infiltrate in alcoholic liver disease. Hum Pathol 2002;33:1170–4.
      OpenUrlCrossRefPubMedWeb of Science
    21. ↵
      1. Beckett AG,
      2. Livingstone AV,
      3. Hill KR
      . Acute alcoholic hepatitis. BMJ 1961;2:1113–19.
      OpenUrlFREE Full Text
    22. ↵
      1. Harinasuta U,
      2. Zimmerman HJ
      . Alcoholic steatonecrosis. I. Relationship between severity of hepatic disease and presence of Mallory bodies in the liver. Gastroenterology 1971;60:1036–46.
      OpenUrlPubMed
    23. ↵
      1. Promrat K,
      2. Lutchman G,
      3. Uwaifo GI,
      4. et al
      . A pilot study of pioglitazone treatment for nonalcoholic steatohepatitis. Hepatology 2004;39:188–96.
      OpenUrlCrossRefPubMedWeb of Science
    24. ↵
      1. Aithal GP,
      2. Thomas JA,
      3. Kaye PV,
      4. et al
      . Randomized, placebo-controlled trial of pioglitazone in nondiabetic subjects with nonalcoholic steatohepatitis. Gastroenterology 2008;135:1176–84.
      OpenUrlCrossRefPubMedWeb of Science
    25. ↵
      1. Ishak K,
      2. Baptista A,
      3. Bianchi L,
      4. et al
      . Histological grading and staging of chronic hepatitis. J Hepatol 1995;22:696–9.
      OpenUrlCrossRefPubMedWeb of Science
    26. ↵
      1. Lefkowitch JH,
      2. Arborgh BA,
      3. Scheuer PJ
      . Oxyphilic granular hepatocytes. Mitochondrion-rich liver cells in hepatic disease. Am J Clin Pathol 1980;74:432–41.
      OpenUrlPubMedWeb of Science
    27. ↵
      1. Lonardo A
      . Fatty liver and nonalcoholic steatohepatitis. Where do we stand and where are we going? Dig Dis 1999;17:80–9.
      OpenUrlCrossRefPubMedWeb of Science
    28. ↵
      1. Guzman M,
      2. Castro J
      . Zonation of fatty acid metabolism in rat liver. Biochem J 1989;264:107–13.
      OpenUrlPubMedWeb of Science
    29. ↵
      1. Schwimmer JB,
      2. Behling C,
      3. Newbury R,
      4. et al
      . Histopathology of pediatric nonalcoholic fatty liver disease. Hepatology 2005;42:641–9.
      OpenUrlCrossRefPubMedWeb of Science
    30. ↵
      1. Brunt EM
      . Nonalcoholic steatohepatitis: pathologic features and differential diagnosis. Semin Diagn Pathol 2005;22:330–8.
      OpenUrlCrossRefPubMedWeb of Science
    31. ↵
      1. Neuschwander-Tetri BA,
      2. Brunt EM,
      3. Wehmeier KR,
      4. et al
      . Improved nonalcoholic steatohepatitis after 48 weeks of treatment with the PPAR-gamma ligand rosiglitazone. Hepatology 2003;38:1008–17.
      OpenUrlCrossRefPubMedWeb of Science
    32. ↵
      1. Abrams GA,
      2. Kunde SS,
      3. Lazenby AJ,
      4. et al
      . Portal fibrosis and hepatic steatosis in morbidly obese subjects: a spectrum of nonalcoholic fatty liver disease. Hepatology 2004;40:475–83.
      OpenUrlCrossRefPubMedWeb of Science
    33. ↵
      1. Kazemi-Shirazi L,
      2. Veloso MP,
      3. Frommlet F,
      4. et al
      . Differentiation of nonalcoholic from alcoholic steatohepatitis: are routine laboratory markers useful? Wien Klin Wochenschr 2008;120:25–30.
      OpenUrlCrossRefPubMedWeb of Science
    34. ↵
      1. Harrison SA,
      2. Oliver D,
      3. Arnold HL,
      4. et al
      . Development and validation of a simple NAFLD clinical scoring system for identifying patients without advanced disease. Gut 2008;57:1441–7.
      OpenUrlAbstract/FREE Full Text
    35. ↵
      1. Angulo P,
      2. Keach JC,
      3. Batts KP,
      4. et al
      . Independent predictors of liver fibrosis in patients with nonalcoholic steatohepatitis. Hepatology 1999;30:1356–62.
      OpenUrlCrossRefPubMedWeb of Science
    36. ↵
      1. Ratziu V,
      2. Giral P,
      3. Charlotte F,
      4. et al
      . Liver fibrosis in overweight patients. Gastroenterology 2000;118:1117–23.
      OpenUrlCrossRefPubMedWeb of Science
    37. ↵
      1. Dixon JB,
      2. Bhathal PS,
      3. O'Brien PE
      . Nonalcoholic fatty liver disease: predictors of nonalcoholic steatohepatitis and liver fibrosis in the severely obese. Gastroenterology 2001;121:91–100.
      OpenUrlCrossRefPubMedWeb of Science
    38. ↵
      1. George DK,
      2. Goldwurm S,
      3. MacDonald GA,
      4. et al
      . Increased hepatic iron concentration in nonalcoholic steatohepatitis is associated with increased fibrosis. Gastroenterology 1998;114:311–18.
      OpenUrlCrossRefPubMedWeb of Science
    39. ↵
      1. Younossi ZM,
      2. Gramlich T,
      3. Bacon BR,
      4. et al
      . Hepatic iron and nonalcoholic fatty liver disease. Hepatology 1999;30:847–50.
      OpenUrlCrossRefPubMedWeb of Science
    40. ↵
      1. Enomoto N,
      2. Ikejima K,
      3. Bradford B,
      4. et al
      . Alcohol causes both tolerance and sensitization of rat Kupffer cells via mechanisms dependent on endotoxin. Gastroenterology 1998;115:443–51.
      OpenUrlCrossRefPubMedWeb of Science
    41. ↵
      1. Wigg AJ,
      2. Roberts-Thomson IC,
      3. Dymock RB,
      4. et al
      . The role of small intestinal bacterial overgrowth, intestinal permeability, endotoxaemia, and tumour necrosis factor alpha in the pathogenesis of non-alcoholic steatohepatitis. Gut 2001;48:206–11.
      OpenUrlAbstract/FREE Full Text
    42. ↵
      1. Solga SF,
      2. Diehl AM
      . Non-alcoholic fatty liver disease: lumen-liver interactions and possible role for probiotics. J Hepatol 2003;38:681–7.
      OpenUrlCrossRefPubMedWeb of Science
    43. ↵
      1. Nagata K,
      2. Suzuki H,
      3. Sakaguchi S
      . Common pathogenic mechanism in development progression of liver injury caused by non-alcoholic or alcoholic steatohepatitis. J Toxicol Sci 2007;32:453–68.
      OpenUrlCrossRefPubMed
    44. ↵
      1. Szabo G,
      2. Mandrekar P,
      3. Dolganiuc A
      . Innate immune response and hepatic inflammation. Semin Liver Dis 2007;27:339–50.
      OpenUrlCrossRefPubMedWeb of Science
    45. ↵
      1. Tiegs G
      . Cellular and cytokine-mediated mechanisms of inflammation and its modulation in immune-mediated liver injury. Z Gastroenterol 2007;45:63–70.
      OpenUrlCrossRefPubMedWeb of Science
    46. ↵
      1. Argo CK,
      2. Northup PG,
      3. Al-Osaimi AM,
      4. et al
      . Systematic review of risk factors for fibrosis progression in non-alcoholic steatohepatitis. J Hepatol 2009;51:371–9.
      OpenUrlCrossRefPubMedWeb of Science

    Footnotes

    • PVK and GPA contributed equally.

    • Competing interests None.

    • Ethics approval Ethics approval was provided by the Nottingham Ethics Committee.

    • Provenance and peer review Not commissioned; externally peer reviewed.