The natural history of nonalcoholic fatty liver disease: a clinical histopathological study

Similarities and differences in outcomes of cirrhosis due to nonalcoholic steatohepatitis and hepatitis C

The objective of this study was to prospectively define outcomes of cirrhosis due to nonalcoholic steatohepatitis (NASH) and compare them with those associated with hepatitis C virus (HCV) infection. We compared 152 patients with cirrhosis due to NASH with 150 matched patients with cirrhosis due to HCV. Over 10 years, 29/152 patients with cirrhosis due to NASH died compared with 44/150 patients with HCV (P < .04). This was mainly due to the lower mortality rate in patients with Child class A cirrhosis due to NASH versus HCV (3/74 vs. 15/75; P < .004). There were no significant across-group differences in mortality in patients with Child class B or C cirrhosis. Sepsis was the most common cause of death in both groups; patients with NASH had a higher cardiac mortality (8/152 vs. 1/150; P < .03). Patients with Child class A cirrhosis due to NASH also had a significantly lower risk of decompensation, defined by a 2-point increase in Child-Turcotte-Pugh score (P < .007). Cirrhosis due to NASH was associated with a lower rate of development of ascites (14/101 vs. 40/97 patients at risk; P < .006). NASH also had a significantly lower risk of development of hepatocellular carcinoma (10/149 vs. 25/147 patients at risk; P < .01). In conclusion, compensated cirrhosis due to NASH is associated with a lower mortality rate compared with that due to HCV. It is also associated with a lower rate of development of ascites, hyperbilirubinemia, and hepatocellular carcinoma. However, cardiovascular mortality is greater in patients with NASH.

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.

Computed Tomography Features of Nonalcoholic Steatohepatitis With Histopathologic Correlation

OBJECTIVE

This study was conducted to describe the computed tomography (CT) features of nonalcoholic steatohepatitis (NASH) and to evaluate if the CT features could be used to diagnose and stage NASH.

METHODS

From 1994 until 2004, pathology records revealed 68 patients with NASH. Of these, 12 patients underwent CT scans before (n=6), on the same day as (n=3), or after (n=3) a liver biopsy. Using the same database, 9 patients with steatosis alone evaluated with a CT scan before (n=2), on the same day as (n=3), or after (n=4) the liver biopsy were selected as a control group. Two radiologists measured liver attenuation (compared with spleen) and assessed the pattern of steatosis, craniocaudal liver span, caudate-to-right lobe ratio, preportal space distance, and presence of porta hepatis lymph nodes and ascites. Biopsy specimens were assessed by a pathologist, and the degree of necroinflammatory activity, steatosis, and fibrosis was determined. Histopathologic and CT findings were compared between patients with NASH and patients with steatosis alone using the Mann-Whitney U test and Fisher exact test.

RESULTS

In patients with NASH, the mean liver-to-spleen attenuation ratio was 0.66 (range: 0.1-1.1). Steatosis was diffuse (n=9), geographic or nonlobar (n=2), or diffuse with an area of focal sparing (n=1). The liver craniocaudal span varied from 17.5 to 25.5 cm (mean=21.4 cm), and hepatomegaly was present in 11 (91.7%) patients. The caudate-to-right-lobe ratio (mean=0.43) and preportal space (mean=4.5 mm) were normal in all cases. Porta hepatis lymph nodes were present in 7 (58.3%) patients; their mean dimensions were 16 mmx11 mm. Ascites was absent in all patients. On histopathology, the degree of necroinflammatory activity was mild (n=9), moderate (n=1), or severe (n=2). The degree of steatosis was 33% to 66% (n=5) or >67% (n=7). All but 3 patients had fibrosis; 6 had focal nonbridging fibrosis, 1 had multifocal nonbridging fibrosis, and 2 had bridging fibrosis. There was a significant correlation between the degree of steatosis on pathologic examination and the liver-to-spleen attenuation ratio on CT (P=0.048). The severity of inflammation and stage of fibrosis on pathologic examination did not correlate with the CT features. Among patients with steatosis alone, the mean liver-to-spleen attenuation ratio was 0.80 (range: 0.3-1.2); the craniocaudal liver span varied from 12 to 20 cm (mean=16 cm); hepatomegaly was present in 2 (22.2%) patients; the caudate-to-right lobe ratio was normal in all patients, with a mean of 0.36 (range: 0.22-0.47); the preportal space distance was enlarged in 2 cases (mean=7.5 mm, range: 1-16 mm); porta hepatis lymph nodes were present in 7 (77.8%) patients, and their mean dimensions were 11 mmx8 mm (large axis range: 6-19 mm, short axis range: 4-14 mm); and no patient had ascites. There was a significant difference in the craniocaudal liver span between patients with NASH (mean=21 cm) and patients with steatosis (mean=16 cm) (P<0.05). The caudate-to-right-lobe ratio was also significantly different between patients with NASH (mean=0.43) and patients with steatosis (mean=0.36) (P<0.05). There were no significant differences in liver-to-spleen attenuation ratios, measurements of preportal space, or the presence of porta hepatic lymph nodes.

CONCLUSION

The CT features of NASH include steatosis, hepatomegaly, and porta hepatis lymph nodes, and the liver-to-spleen attenuation ratio correlated with the degree of steatosis on histopathology. Patients with NASH had a greater liver span and increased caudate-to-right-lobe-ratio compared with patients with steatosis alone.

Demographic and clinicopathological characteristics of nonalcoholic fatty liver disease in the East-Southeastern Anatolia regions in Turkey

OBJECTIVE

To identify the demographic and clinicopathological characteristics of patients diagnosed with nonalcoholic fatty liver disease (NAFLD) and the risk factors for fibrosis based on histopathological findings in East-Southeastern Anatolia regions in Turkey.

SUBJECTS AND METHODS

The study included a total of 93 patients diagnosed with NAFLD from 5 different centers. Histopathological findings were evaluated by dividing them into four categories using Matteoni classifications. Cases with fibrosis were further evaluated using Brunt classifications.

RESULTS

The patients with a nonalcoholic fatty liver were in the 3rd and 4th decade age groups. The mean age was 38 years, 76% of the patients were male, 85% were overweight, 37% were obese, 18% had type 2 diabetes mellitus, and 80.6% had hyperlipidemia. A multiple regression analysis showed that age, type 2 diabetes mellitus, and aspartate aminotransferase (AST) levels were linked with the severity of the disease. Of the 93 patients, 55 (59.1%) had fibrosis, of which 10.8% were classified as severe. The severity of fibrosis was significantly higher in obese patients.

CONCLUSIONS

The risk factors for severity of NAFLD included advanced age, type 2 diabetes mellitus and serum AST level, while the risk factor for the severity of fibrosis was obesity.

Treatment strategies in nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is an increasingly recognized health problem. Increased fat accumulation in the liver is observed in 20-30% of the population in the Western world, and in approximately 10% of this cohort it is associated with nonalcoholic steatohepatitis, which is characterized by inflammation and fibrosis. Disease presentation of NAFLD ranges from asymptomatic disease to cirrhosis with the complication of liver failure and hepatocellular carcinoma. NAFLD is suspected on the basis of various clinical aspects (an elevated alanine aminotransferase concentration, presence of obesity and diabetes) that alone are not sufficient to establish diagnosis or prognosis. The major diagnostic procedure is liver biopsy, which allows assessment of liver injury. In most cases, NAFLD is associated with insulin resistance, which is therefore the target of most current NAFLD treatment modalities. Various treatment strategies such as weight loss and/or exercise, thiazolidinediones, metformin, lipid-lowering agents and antioxidants have been studied. So far, no single intervention has convincingly improved liver histology. It is recommended that patients at high risk of developing advanced liver disease, and who are not part of controlled studies, should receive nutritional counseling and take physical exercise to achieve moderate weight loss and improve insulin sensitivity.

Approach to the diagnosis and treatment of nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is a common cause of chronic liver disease in the United States. It describes several clinicopathologic entities from simple hepatic steatosis to nonalcoholic steatohepatitis, cirrhosis, and hepatocellular carcinoma. This article describes the epidemiology, clinical features, natural history, and pathogenesis of NAFLD.

Effect of lactulose on establishment of a rat non-alcoholic steatohepatitis model

AIM

To explore the relationship between changes of intestinal environment and pathogenesis of non-alcoholic steatohepatitis (NASH).

METHODS

Forty-two Sprague-Dawley rats were randomly divided into model group (n = 24), treatment group (n = 12), and control group (n = 6). The rats of model and treatment groups were given high-fat diet, and those of the control group were given normal diet. Furthermore, the rats of treatment group were given lactulose after 8 wk of high-fat diet. Twelve rats of the model group were killed at 8 wk of high-fat diet. At the 16 wk the rats of treatment group, control group, and the rest of the model group were killed. The serum levels of aminotransferase were measured and the histology of livers was observed by H and E staining.

RESULTS

The livers of rats presented the pathological features of steatohepatitis with higher serum levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in the model group after 16 wk. Compared to the model group, the serum levels of ALT and AST in treatment group decreased significantly and were close to the normal group, and the hepatic inflammation scores also decreased markedly than those in the model group after 16 wk (5.83+/-2.02 vs 3.63+/-0.64, P<0.05), but were still higher than those in the model group after 8 wk (3.63+/-0.64 vs 1.98+/-0.90, P<0.05). However, the degree of hepatic steatosis had no changes in treatment group compared to the model group after 16 wk.

CONCLUSION

Lactulose could ameliorate the hepatic inflammation of rats with steatohepatitis induced by fat-rich diet, but could not completely prevent the development of steatohepatitis. It is suggested that intestinal environmental changes such as intestinal bacteria overgrowth, are one of the important factors in the pathogenesis of NASH.

Increased orocecal transit time in patients with nonalcoholic fatty liver disease

Intestinal bacterial overgrowth (IBO) has been suggested to play a pathogenic role in patients with nonalcoholic fatty liver disease (NAFLD). Delayed intestinal transit may contribute to IBO development. Ten nondiabetic patients with NAFLD and abnormal liver enzymes were recruited. Ten healthy individuals, matched by sex, age, and body mass index, were used as controls. Orocecal transit time (OCTT) was measured by the lactulose breath test. Anti-endotoxin core antibodies (EndoCAb) were determined. The effect of oral norfloxacin (400 mg BID during 2 weeks) on liver enzymes, lactulose breath test, and EndoCAb was also studied. NAFLD patients had higher basal breathed H2 and prolonged OCTT compared to controls (127 +/- 61 vs. 57 +/- 23 min, respectively; P = 0.0037). EndoCAb titers were similar in NAFLD patients and controls. Norfloxacin administration had no effect on ALT levels, lactulose breath test, or EndoCAb titers in patients with NAFLD. The present data show evidence of deranged intestinal motility in nondiabetic patients with NAFLD and support the hypothesis that NAFLD could be linked to endotoxin-induced liver damage of intestinal origin.

Fibrosis heterogeneity in nonalcoholic steatohepatitis and hepatitis C virus needle core biopsy specimens

We examined 46 nonalcoholic steatohepatitis (NASH) and 52 hepatitis C virus (HCV) biopsy specimens to determine the magnitude of fibrosis heterogeneity and minimum length for accurate fibrosis staging. Three fibrosis scores were recorded: lowest regional, highest regional, and most common overall. Mean specimen lengths were 1.6 and 1.8 cm in NASH and HCV, respectively (P = .283). Mean (highest minus lowest) fibrosis heterogeneity scores (highest regional fibrosis - lowest regional fibrosis) were 3.7 and 2.0 in NASH and HCV, respectively (P < .001). Of 36 NASH specimens longer than 1.0 cm, 31 (86%) had the highest regional fibrosis in the deepest sampled parenchyma. Shorter specimens were associated significantly with greater fibrosis heterogeneity in NASH (coefficient, -1.3; P < .001) but not in HCV (P = .901). NASH specimens longer than 1.6 cm had significantly lower mean heterogeneity scores than specimens 1.6 cm or shorter (1.2 vs 3.4; P = .012). In NASH, fibrosis heterogeneity can be substantial and is greater than in HCV, and parenchymal injury, fibrosis, and healing might vary in different regions of the liver. The fibrosis stage in patients with NASH might not be assessed accurately in short specimens. Individual needle cores should be longer than 1.6 cm in NASH for accurate fibrosis staging.

Nonalcoholic steatohepatitis: recent advances from experimental models to clinical management

A condition defined as nonalcoholic fatty liver disease (NAFLD) is frequently found in humans. Deemed as a benign condition until recently, more emphasis is now put on the potential harmful evolution of the inflammatory form, that is, nonalcoholic steatohepatitis (NASH), toward end-stage liver disease. This review highlights the major morphologic and pathophysiological features of NASH. The link between experimental biochemical findings in animal models and clinical and therapeutic approaches in humans is discussed. Once all the other causes of persistent elevation of serum transaminase levels have been excluded, the diagnosis of NASH can be only confirmed by liver histology. Other noninvasive diagnostic tools, however, are being investigated to assess specific subcellular functions and to allow the follow-up of patients at higher risk for major liver dysfunction. A better understanding of various pathogenic aspects of NASH will help in identifying potential therapeutic approaches in these patients.

Comparison of the natural history of alcoholic and nonalcoholic fatty liver disease

Fatty liver disease represents a common clinical entity. It is classically divided into alcoholic fatty liver disease (AFLD) and nonalcoholic fatty liver disease (NAFLD). Whereas AFLD occurs in as many as 10 million Americans, NAFLD represents the most common chronic liver disease and is the most common cause of liver enzyme abnormalities in the United States. Both diseases encompass the clinical spectrum of steatosis, steatohepatitis, and cirrhosis. Although they are histologically indistinct, AFLD and NAFLD follow different clinical courses. This article compares the natural history of these diseases.

Induction of macrophage scavenger receptor MARCO in nonalcoholic steatohepatitis indicates possible involvement of endotoxin in its pathogenic process

Nonalcoholic steatohepatitis (NASH) is one of the life-threatening hepatic diseases; however, its pathogenesis is still unknown. To evaluate the causative role of hyperlipidaemia and high-fat diet, we compared C57BL/6 mice with inherited hyperlipidaemic model mice (LDLR(-/-)mice and ApoE(-/-) mice) fed a normal or a high-fat diet. LDLR(-/-) and ApoE(-/-) mice fed the normal diet showed significantly higher serum cholesterol level than that of C57BL/6 mice fed the high-fat diet. These mice, however, have shown neither significant elevation of serum alanine transaminase (ALT) level nor histopathologic features of steatohepatitis. High-fat diet groups of all three strains showed histopathological characteristics of steatohepatitis with elevated serum ALT levels and high expression of macrophage scavenger receptor MARCO mRNA in the liver. Semiquantitative endotoxin analysis showed an elevated serum endotoxin level in the portal vein but not in the vena cava in ApoE(-/-) mice fed the high-fat diet. These results indicate that long-term feeding of a high-fat diet induces NASH, whereas hyperlipidaemia alone is not enough to induce NASH. Liver-restricted induction of MARCO in mice with high-fat diet and portal endotoxaemia in ApoE(-/-) mice fed the high-fat diet suggest the possible involvement of endotoxin in the pathogenesis of NASH.

The histological course of nonalcoholic fatty liver disease: a longitudinal study of 103 patients with sequential liver biopsies

BACKGROUND/AIMS

The histological course of nonalcoholic fatty liver disease (NAFLD) remains undescribed. Therefore, we examined the liver histology of NAFLD patients who had undergone sequential liver biopsies.

METHODS

Data on 103 patients who underwent serial liver biopsies in the absence of effective treatment were reviewed, and biopsies scored in a blind fashion.

RESULTS

Mean interval between biopsies was 3.2+/-3.0 years (range 0.7-21.3). Fibrosis stage apparently progressed in 37%, remained stable in 34% and regressed in 29%. Severity of steatosis, inflammation, hepatocyte ballooning and Mallory's hyaline improved significantly. Aminotransferases decreased significantly between biopsies, paralleling improvement in steatosis and inflammatory features but not fibrosis stage. The rate of fibrosis change ranged from -2.05 to 1.7 stages/year. By multivariate analysis, diabetes (P = 0.007) and low initial fibrosis stage (P < 0.001) were associated with higher rate of fibrosis progression, as was higher body mass index (P = 0.008) when cirrhotics were excluded.

CONCLUSIONS

Fibrosis in NAFLD progresses slowly over time with considerable variability in the rate of changes among patients. Changes of aminotransferases do not parallel changes in fibrosis stage. Diabetic patients with elevated BMI and low fibrosis stage are at risk for higher rates of fibrosis progression.

Nonalcoholic fatty liver disease: a clinical review

Nonalcoholic fatty liver disease may be the most common liver disease in the United States, with a high prevalence in the obese, type 2 diabetic population, and it is probably underestimated as a cause for cirrhosis. Clinicopathologically, it represents a wide spectrum of histologic abnormalities and clinical outcomes, ranging from benign hepatic steatosis to cirrhosis. Pathophysiologically, insulin resistance is thought to be pivotal in the development of steatosis, after which a second oxidative stressor produces lipid peroxidation and nonalcoholic steatohepatitis (NASH). Liver biopsy is the gold standard for diagnosis and prognosis. The need for an effective treatment is both clear and urgent, yet in the absence of proven therapies, treatment is directed toward weight loss and comorbidity management. For patients with NAFLD at risk of disease progression, there is a lack of large, randomized, placebo-controlled trials of adequate treatment duration, with baseline stratification according to histologic severity.

A pilot study of vitamin E versus vitamin E and pioglitazone for the treatment of nonalcoholic steatohepatitis

BACKGROUND & AIMS

Insulin resistance and oxidative stress contribute to the pathogenesis of nonalcoholic steatohepatitis (NASH). We conducted a pilot study for the following reasons: (1) to test the hypothesis that a combination of an antioxidant (vitamin E) and an insulin sensitizer (pioglitazone) would be superior to vitamin E alone for the treatment of NASH, and (2) to define the effects of these interventions on insulin-sensitive metabolic functions and correlate the effects with changes in liver histology.

METHODS

A randomized prospective trial was performed to compare the efficacy and safety of vitamin E alone (400 IU/day) vs. vitamin E (400 IU/day) and pioglitazone (30 mg/day) in nondiabetic, noncirrhotic subjects with NASH. Metabolic functions were assessed by a 2-step, hyperinsulinemic (10 and 40 mU/m2/min) euglycemic clamp.

RESULTS

A total of 10 patients were randomized to each arm. Two patients on combination therapy discontinued treatment; one because of pregnancy and the other because of hepatotoxicity. Treatment with vitamin E only produced a significant decrease in steatosis (mean grade, 2.2 vs. 1.4; P < .02). Compared with baseline, combination therapy produced a significant decrease in steatosis (mean, 2.3 vs. 1; P < .002), cytologic ballooning (1.3 vs. 0.2; P < .01), Mallory's hyaline (0.7 vs. 0.2; P < .04), and pericellular fibrosis (1.2 vs. 0.6; P < .03). Although vitamin E had no significant effects, combination therapy produced a significant increase in metabolic clearance of glucose and a decrease in fasting free fatty acid (FFA) and insulin. The decrease in fasting FFA and insulin independently predicted improvement in hepatic steatosis and cytologic ballooning.

CONCLUSIONS

A combination of vitamin E and pioglitazone produces a greater improvement in NASH histology. The improvement in steatosis and cytologic ballooning are related to treatment-associated decreases in fasting FFA and insulin levels.

Non-alcoholic fatty liver disease/non-alcoholic steatohepatitis (NAFLD/NASH): diagnosis and clinical course

Non-alcoholic fatty liver disease (NAFLD) is a frequent syndrome encompassing fatty liver alone and steatohepatitis (NASH). Often asymptomatic, the suspicion arises because of abnormal aminotransferases or a bright liver on abdominal ultrasound. It should be suspected during evaluation of associated conditions as obesity, diabetes or dyslipidaemia. The diagnostic evaluation must exclude other potential causes of liver disease and may include a liver biopsy, the only method able to confirm features of necroinflammation and fibrosis that define NASH and its prognostic implications. Indeed, the presence of necroinflammation has been associated with a significant risk of progression to cirrhosis and eventually hepatocellular carcinoma. Age >45 years, obesity and diabetes have also been associated with an increased risk of liver fibrosis and progression to cirrhosis. Given the high prevalence of NAFLD, general measures of life-style changes, focusing on exercise, diet, and total alcohol abstinence, should be implemented before a liver biopsy is considered.

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 fatty liver disease and nonalcoholic steatohepatitis

Nonalcoholic fatty liver disease (NAFLD) is a well-recognized form of chronic liver disease affecting both children and adults that has gained increased recognition. Recently NAFLD has been associated with insulin resistance and its incidence and prevalence is likely increasing, paralleling the rise in obesity and diabetes mellitus in the United States. The article includes current thoughts on the natural history and pathogenesis of NAFLD and describes current trends in the diagnosis and treatment of this condition.

Natural history of nonalcoholic steatohepatitis: a longitudinal study of repeat liver biopsies

Nonalcoholic steatohepatitis may cause severe fibrosis, cirrhosis, and hepatocellular carcinoma, but supporting evidence is based on indirect data. Few publications have examined the results of repeat liver biopsies to evaluate progression of fibrosis. The aims of this study were to assess rate of fibrosis progression in untreated patients with nonalcoholic steatohepatitis and to identify associated variables. Among 106 patients, a second liver biopsy was proposed to those who had undergone their first liver biopsy at least 3 years before. None of them had been given pharmacological therapy. Liver biopsy samples were evaluated blindly. Variables were compared between patients with (group P) and without (group NP) fibrosis progression, using a Wilcoxon rank-sum test for numerical variables and a difference of two binomial proportions for categorical ones. Twenty-two patients (median age, 45 years; age range, 20-69 years; 13 women; diabetes in 8 patients, obesity in 10 patients) underwent a second liver biopsy 4.3 years (range, 3.0-14.3 years) after the first. Fibrosis progression was found in 7 patients in group P (31.8%), no progression was found in 15 patients in group NP. There were no differences between both groups regarding age, gender, diabetes, hyperlipidemia, ALT levels, AST-to-ALT ratio levels, albumin levels, prothrombin activity, steatosis, or inflammation. Obesity was significantly more prevalent in group P (86%) than in group NP (27%; P =.01). Basal body mass index was higher in group P (median, 33.2; range, 29.1-38.2) than in group NP (median, 29.0; range, 24.0-38.1; P =.024). Time between biopsies was not different between groups. In conclusion, progression of liver fibrosis was found in a third of nonalcoholic steatohepatitis patients 4.3 years after the first liver biopsy, and obesity and body mass index were the only associated factors with such progression.

The clinical features, diagnosis and natural history of nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) has emerged as the most common chronic liver disease in the United States. The histologic spectrum of NAFLD ranges from steatosis liver alone to nonalcoholic steatohepatitis (NASH), which is the most serious form of NAFLD. NASH is a progressive fibrotic disease, in which cirrhosis and liver-related death occur in up to 20% and 12%, respectively, over a 10-year period. NASH-associated cirrhosis also can develop into subacute liver failure, progress to hepatocellular carcinoma, and reoccur post-transplantation. In contrast, steatosis alone has a more benign clinical course, although progression to cirrhosis has occurred in 3% of these patients. The major risk factors for fibrosis include diabetes or obesity, an aspartate aminotransferase/alanine aminotransferase ratio of greater than 1, age older than 50, and hepatic histology.

Association between fatty liver and hyperlipidemia

AIM: To investigate the association between the formation of fatty liver and the phenotypes of hyperlipidemia.

METHODS: A total of 258 patients with hyperlipidemia were found in 413 patients with fatty liver, and 61 cases of hyperlipidemia in non-fatty liver patients were selected randomly as controls. The complications and liver function abnormalities were compared between two groups.

RESULTS: The proportion of hypertriglyceridemia and mixed hyperlipidemia was higher in the patients with fatty liver than non-fatty liver. Odds ratios (OR) of finding fatty liver in the patients with mixed hyperlipidemia and hypertrigly-ceridemia were 5.966 and 2.960 respectively, relative to hypercholesterolemia. The percentage of complications of typeⅡdiabetes mellitus, obesity, hypertension, hyperuris-emia and the evelation of serum alanine aminotransferase (ALT), -glutamyltransferase (GGT) were higher in patients with fatty liver than non-fatty liver. But, there were no differences in coincidence of diabetes mellitus, obesity, hyperten-sion, hyperurisemia, coronary heart disease, choelithiasis among various phenotypes of hyperlipidemia.

CONCLUSION: The pathogenesis of fatty liver can be related to mixed hyperlipidemia and hypertriglyceridemia. The complications of patients with fatty liver may be more common than those with non-fatty liver, but have no differences of complications among various phenotypes of hyperlipidemia.

Advances in the Understanding and Treatment of Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) is a well recognised form of chronic liver disease that has recently gained greater recognition. Originally described in the late 1950s, NAFLD is currently considered the leading cause of abnormal liver enzyme levels in the US, closely paralleling the increase in obesity and diabetes mellitus. NAFLD has a worldwide distribution, affecting both adults and children, and typically is seen in association with obesity, diabetes, hypertension and hypertriglyceridaemia. Most patients are asymptomatic and usually present with mild elevations in aminotransferases. The natural history of NAFLD is not clearly defined but progression to cirrhosis and end-stage liver disease is well recognised in some patients. The accumulation of hepatic steatosis is thought to occur initially, primarily through hepatic and peripheral insulin resistance, which leads to altered glucose and free fatty acid metabolism. The progression from simple fatty liver to more severe forms of NAFLD (nonalcoholic steatohepatitis and cirrhosis) is much less clear but evidence suggests that oxidative stress may preferentially enhance proinflammatory cytokines, which leads to cellular adaptations and dysfunction followed by development of inflammation, necrosis and fibrosis. Therapeutic modalities remain limited and are largely focused on correcting the underlying insulin resistance or reducing oxidative stress. However, at the present time, there are several limitations to the current potential therapies, mainly because of the lack of large-scale, prospective, randomised studies, as well as clearly defined histological endpoints. Ultimately, the future for potential therapeutic modalities to treat this disease are quite promising, but further research is needed to clearly demonstrate which therapy or therapies will be effective at eliminating fatty liver disease and its potential complications.