Steatohepatitis associated with limb lipodystrophy

Past, present and future perspectives in nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) was first described as a distinct clinical entity four decades ago. However, the condition has become the centre of attention within hepatology owing to its high prevalence and growing contribution to the burden of end-stage liver disease in the general population. This Perspective provides an overview on the development of knowledge related to NAFLD with a focus on landmark findings that have influenced current paradigms and key knowledge gaps that need to be filled to make progress. Specifically, a timeline of scientific discovery of both basic disease mechanisms (with a focus on human data) and the evolution of knowledge about the clinical course of the disease is provided and related to current approaches to treat and eventually prevent NAFLD.

Non-alcoholic fatty liver disease (NAFLD) in different populations: A clinical and epidemiological study – sample of São José do Rio Preto

SUMMARY Introduction: NAFLD is an heterogeneous condition that includes steatosis and non-alcoholic steatohepatitis (NASH), in the absence of significant alcohol consumption, reaching 30% of the population. The most common risk factors are: age, gender, ethnicity, diabetes mellitus (DM), obesity, predisposition, metabolic syndrome (MS), insulin resistance (IR), drugs, and polycystic ovary syndrome. Objective: To describe the profile of patients with NAFLD seen at Hospital de Base of Rio Preto, in the state of São Paulo. Method: Patients with NAFLD were assessed, with medical and epidemiological data collected after informed consent. Results: Of the 62 patients evaluated, 76% were women, 73% Caucasians, and 71% were aged between 50 and 69 years and had no symptoms. Ultrasonography results showed steatosis in 84%. NASH was diagnosed in 61% of the sample. 21 patients underwent liver biopsy, of which 36% had cirrhosis, 1 had liver cancer, and 1 pure steatosis (5% each). Risk factors were found in 70% of patients with metabolic syndrome, 87% with increased waist circumference, 63% with dyslipidemia, 61% (n=38) with high blood pressure (HBP), 28% with DM, 52% physically inactive, and 44% with insulin resistance (IR) (HOMA> 3.5). There was an association between IR and NASH (p=0.013), IR and obesity (p=0.027), IR and MS (p=0.006), and MS and steatosis on medical ultrasound (USG) (p=0.014). Conclusion: The most frequent risk factors were MS and its variables: increased waist circumference, dyslipidemia and HBP. This underscores the importance of metabolic control in NAFLD and confirms its role as the hepatic component of metabolic syndrome.

Comparison of contrast-enhanced ultrasonography with grey-scale ultrasonography and contrast-enhanced computed tomography in diagnosing focal fatty liver infiltrations and focal fatty sparing

PURPOSE

Fatty liver infiltrations and fatty sparing impair diagnostic performance of grey-scale ultrasonography in differentiating malignant and benign focal liver lesions. In the study, we present our experience in diagnosing focal fatty liver infiltrations and focal fatty sparing with contrastenhanced ultrasonography (CEUS) in comparison to grey-scale ultrasonography and contrast-enhanced computed tomography (CECT).

MATERIAL AND METHOD

The retrospective study group (n=82 patients), included 44 (53.7%) men, 38 (46.3%) women (aged 29- 81 years, mean 55.8 years) with 48 focal fatty liver infiltrations and 34 focal fatty sparing. All patients underwent grey-scale ultrasonography (US), CEUS using SonoVue® and CECT executed within the 7 days.

RESULTS

With US, CEUS and CECT focal fatty liver infiltrations were diagnosed in 22, 46 and 44 cases, respectively. The following values were obtained: sensitivity - 45.8%, 95.8% and 91.7%, specificity - 100% for all, accuracy - 95.2%, 99.6% and 99.3%, respectively. Focal fatty sparing was diagnosed in 16, 31 and 30 cases, respectively. The following values were obtained: sensitivity - 47.1%, 91.2% and 88.2%, specificity - 99.8%, 100% and 100%, accuracy - 95.6%, 99.4% and 99.3%, respectively. No statistically significant differences were found in sensitivity of diagnosing focal fatty liver infiltrations and focal fatty liver sparing between CEUS and CECT. Sensitivity of grey-scale ultrasonography was significantly lower when compared to those of CEUS and CECT (p<0.001).

CONCLUSION

CEUS is as sensitive as CECT in focal fatty infiltrations and focal fatty sparing diagnosing. However, CEUS provides more information than CECT about the vasculature and enhancement pattern of focal fatty liver infiltrations.

Nonalcoholic Steatohepatitis: Diagnostic Challenges

This article reviews diagnostic criteria for nonalcoholic steatohepatitis (NASH), current grading and staging methodology, and diagnostic challenges and pitfalls in routine practice. Current practice guidelines and prognostic and treatment considerations are discussed. The clinical diagnosis of nonalcoholic fatty liver disease may represent stable disease without progressive liver damage, in the form of nonalcoholic fatty liver (NAFL), or aggressive disease that will progress to advanced fibrosis, in the form of NASH. NASH is diagnosed from a liver biopsy after assessment by a pathologist to distinguish NASH from NAFL (and other histologic mimics of NASH); this distinction is critical for patient management.

A myriad of pathways to NASH

Nonalcoholic steatohepatitis (NASH) is defined histopathologically by the presence of macrovesicular steatosis, cellular ballooning, and inflammation. NASH represents a complex multifactorial disease that typically occurs within the context of the metabolic syndrome. NASH lacks homogeneity, and other forms of NASH can present atypically. Less than 50% of patients with NASH respond to pharmacologic treatment, which speaks to this heterogeneity. The authors discuss drugs, disease entities, and nutritional states that can cause or exacerbate underlying NASH indirectly through worsening insulin resistance or directly by interfering with lipid metabolism, promoting oxidative injury, or activating inflammatory pathways.

Acquired generalized lipodystrophy associated with autoimmune hepatitis and low serum C4 level

Lipodystrophies are a group of diseases characterized by loss of fat tissue and are associated with insulin resistance. A six-year-old girl followed with the diagnosis of autoimmune hepatitis showed a severe loss of fat tissue, hyperinsulinemia, impaired glucose tolerance, hypertriglyceridemia and low serum complement 4 (C4) levels. She had coarse facial features with generalized loss of subcutaneous fat and prominent muscularity. Remarkable acanthosis nigricans was present over the neck, axilla, and umbilicus. Two hours after glucose loading, the glucose tolerance test revealed a glucose level of 258 mg/dL, a HbA1c value of 6.8%, and an insulin level of 642.9 mIU/mL, documenting a state of insulin resistance and type 2 diabetes mellitus. Acquired generalized lipodystrophy was diagnosed and metformin with dietary intervention was initiated. Low serum complement levels proved the autoimmune nature of the process. We conclude that the serum complement levels must be investigated in patients with acquired lipodystrophy, particularly when it is associated with autoimmune hepatitis.

Epidemiology and natural history of non-alcoholic steatohepatitis

Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver condition in many parts of the world. This article describes the epidemiology and natural history of this disorder. It also describes current diagnostic and treatment methods and describes future implications NAFLD may have.

The liver and the waistline: Fifty years of growth

Fifty years of the Gastroenterological Society of Australia have witnessed the changing appearance of Australians. Asian immigration has transformed the dominant urban culture from European to Eurasian, with some unique Australian attributes. Meanwhile, global conditions have altered body shape, and our sports-proud country is now fat! Thus, as in North America, Europe, China, and affluent Asia-Pacific countries, prosperity and lifestyle, cheap processed foods coupled with reduced physical activity have created an epidemic of over-nutrition resulting in overweight/obesity. Additional genetic factors are at the core of the apple shape (central obesity) that typifies over-nourished persons with metabolic syndrome. Indigenous Australians, once the leanest and fittest humans, now have exceedingly high rates of obesity and type 2 diabetes, contributing to shorter life expectancy; Asian Australians are also at higher risk. Like non-steroidal anti-inflammatory drugs (NSAIDs) and cigarette smoking, obesity now contributes much to gastrointestinal morbidity and mortality (gastroesophageal reflux disease, cancers, gallstones, endoscopy complications). This review focuses on Australian research about fatty liver, particularly roles of central obesity/insulin resistance in non-alcoholic fatty liver disease/steatohepatitis (NAFLD/NASH). The outputs include many highly cited original articles and reviews and the first book on NAFLD. Studies have identified community prevalence, clinical outcomes, association with insulin resistance, metabolic syndrome and hypoadiponectinemia, developed and explored animal models for mechanisms of inflammation and fibrosis, conceptualized etiopathogenesis, and demonstrated that NASH can be reversed by lowering body weight and increasing physical activity. The findings have led to development of regional guidelines on NAFLD, the first internationally, and should now inform daily practice of gastroenterologists.

Nonalcoholic fatty liver disease: a practical approach to evaluation and management

Non-alcoholic fatty liver disease (NAFLD) has become one of the most common forms of chronic liver disease in the Western world. The rise in NAFLD is thought to be associated with the prevalence of metabolic syndrome. NASH is a subtype of NAFLD that may progress to cirrhosis and end stage liver disease. Although there are no approved treatment regimens for NAFLD or NASH, a number of different interventions are being tested. Meanwhile, most experts advocate that components of metabolic syndrome should be effectively treated.

Pathogenesis and management issues for non-alcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) has, although it is a very common disorder, only relatively recently gained broader interest among physicians and scientists. Fatty liver has been documented in up to 10 to 15 percent of normal individuals and 70 to 80 percent of obese individuals. Although the pathophysiology of NAFLD is still subject to intensive research, several players and mechanisms have been suggested based on the substantial evidence. Excessive hepatocyte triglyceride accumulation resulting from insulin resistance is the first step in the proposed ‘two hit’ model of the pathogenesis of NAFLD. Oxidative stress resulting from mitochondrial fatty acids oxidation, NF-κB-dependent inflammatory cytokine expression and adipocytokines are all considered to be the potential factors causing second hits which lead to hepatocyte injury, inflammation and fibrosis. Although it was initially believed that NAFLD is a completely benign disorder, histologic follow-up studies have showed that fibrosis progression occurs in about a third of patients. A small number of patients with NAFLD eventually ends up with end-stage liver disease and even hepatocellular carcinoma. Although liver biopsy is currently the only way to confirm the NAFLD diagnosis and distinguish between fatty liver alone and NASH, no guidelines or firm recommendations can still be made as for when and in whom it is necessary. Increased physical activity, gradual weight reduction and in selected cases bariatric surgery remain the mainstay of NAFLD therapy. Studies with pharmacologic agents are showing promising results, but available data are still insufficient to make specific recommendations; their use therefore remains highly individual.

Metabolic liver disease of obesity and role of adipose tissue in the pathogenesis of nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is an increasingly recognized cause of liver-related morbidity and mortality. It can develop secondary to numerous causes but a great majority of NAFLD cases occur in patients who are obese or present with other components of metabolic syndrome (hypertension, dyslipidemia, diabetes). This is called primary NAFLD and insulin resistance plays a key role in its pathogenesis. Obesity is characterized by expanded adipose tissue, which is under a state of chronic inflammation. This disturbs the normal storage and endocrine functions of adipose tissue. In obesity, the secretome (adipokines, cytokines, free fatty acids and other lipid moieties) of fatty tissue is amplified, which through its autocrine, paracrine actions in fat tissue and systemic effects especially in the liver leads to an altered metabolic state with insulin resistance (IR). IR leads to hyperglycemia and reactive hyperinsulinemia, which stimulates lipid-accumulating processes and impairs hepatic lipid metabolism. IR enhances free fatty acid delivery to liver from the adipose tissue storage due to uninhibited lipolysis. These changes result in hepatic abnormal fat accumulation, which may initiate the hepatic IR and further aggravate the altered metabolic state of whole body. Hepatic steatosis can also be explained by the fact that there is enhanced dietary fat delivery and physical inactivity. IR and NAFLD are also seen in various lipodystrophic states in contrary to popular belief that these problems only occur due to excessive adiposity in obesity. Hence, altered physiology of adipose tissue is central to development of IR, metabolic syndrome and NAFLD.

Pediatric nonalcoholic fatty liver disease (NAFLD): a "growing" problem?

Nonalcoholic fatty liver disease (NAFLD) can affect both adults and children. With the current worldwide epidemic of pediatric obesity, pediatric NAFLD is increasingly being diagnosed. It is not exactly identical to NAFLD in adults, and these differences may be due in part to the occurrence of hepatic metabolic derangements typical of NAFLD during periods of active growth (infancy, mid-childhood and puberty). The natural history of pediatric NAFLD is not yet known; however, children with pediatric NAFLD can develop cirrhosis. Although details of disease mechanism in pediatric NAFLD remain unclear, hyperinsulinemia with insulin resistance appears to be critical. Determining the pathogenesis of pediatric NAFLD is likely to enhance our understanding of NAFLD in all age groups and may identify new treatment opportunities. Finding effective ways to prevent pediatric NAFLD is an important issue for children's health.

Non-alcoholic steatohepatitis in children

Non-alcoholic steatohepatitis (NASH) is an important liver disease in children; it can cause cirrhosis in children. The disease mechanism involves hepatic insulin resistance with hyperinsulinemia and changes in certain adipocytokines and inflammatory mediators. The differential diagnosis of childhood NASH includes metabolic disorders, drug hepatotoxicity, and alcoholic hepatitis in adolescent patients. The histologic features in childhood NASH often differ from those in adults who have NASH. Treatment is gradual weight loss through changes in food intake patterns and increased levels of physical activity; the role of drug treatment of NASH in children is an area of ongoing research.

Nonalcoholic fatty liver disease in children

Nonalcoholic fatty liver disease (NAFLD) is likely to reach epidemic proportions in children worldwide in the next decade. NAFLD may be the hepatic aspect of the metabolic syndrome in adults and children. The entire range of liver involvement characterizing NAFLD can occur in children: hepatic macrovesicular steatosis without inflammation, steatosis with inflammation or fibrosis, and cirrhosis. NAFLD may be more severe in children from certain ethnic groups or in association with metabolic disorders characterized by abnormalities in insulin receptor structure and function. Treatment strategies focus on modifying risk factors because specific drug treatments are lacking. Overweight/obesity should be identified as early as possible. Comprehensive clinical management to normalize weight should be instituted immediately to avoid hepatic and nonhepatic complications.

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.

Mitochondria in nonalcoholic fatty liver disease

Nonalcoholic fatty liver (NAFL) is associated with fundamental issues of fat metabolism and insulin resistance. These abnormalities have been linked to impairment of ATP homeostasis, and a growing body of literature has reported mitochondrial abnormalities in various forms of hepatic steatosis. The changes are evident as structural abnormalities, including greatly increased size and the development of crystalline inclusions, and are usually regarded as pathologic, reflecting either a protective or degenerative response to injury. Although the relationships between structural changes,decreased mitochondrial function, and disease states are becoming clearer, the molecular basis for the perturbations is not well understood. Oxidative damage is the most likely causative process and may result in alterations of mitochondrial DNA (mtDNA), stimulated apoptotic pathways, and increased propensity for necrosis.Overall mitochondrial health likely depends on multiple factors including the integrity of the mtDNA, the composition of cellular lipids, lipoprotein trafficking, the balance of pro- and antioxidant factors, and the metabolic demands placed on the liver. Mitochondrial dysfunction may play a role in numerous clinical conditions associated with NAFL, such as hepatocellular carcinoma, lipodystrophy,age-related insulin resistance, gut dysmotility, cryptogenic cirrhosis, a mild form of gaze palsy, and possibly other more severe neurodegenerative diseases. The prominent role of mitochondrial dysfunction in NAFL provides a new and exciting paradigm in which to view this disorder, its complications, and potential dietary and pharmacologic intervention.

Approach to the pathogenesis and treatment of nonalcoholic steatohepatitis

Nonalcoholic steatohepatitis (NASH) represents an advanced stage of fatty liver disease developed in the absence of alcohol abuse. Its increasing prevalence in western countries, the diagnostic difficulties by noninvasive tests, and the possibility of progression to advanced fibrosis and even cirrhosis make NASH a challenge for hepatologists. NASH is frequently associated with type 2 diabetes and the metabolic syndrome, and several genetic and acquired factors are involved in its pathogenesis. Insulin resistance plays a central role in the development of a steatotic liver, which becomes vulnerable to additional injuries. Several cyclic mechanisms leading to self-enhancement of insulin resistance and hepatic accumulation of fat have been recently identified. Excess intracellular fatty acids, oxidant stress, tumor necrosis factor-alpha, and mitochondrial dysfunction are causes of hepatocellular injury, thereby leading to disease progression and to the establishment of NASH. Intestinal bacterial overgrowth also plays a role, by increasing production of endogenous ethanol and proinflammatory cytokines. Therapeutic strategies aimed at modulating insulin resistance, normalizing lipoprotein metabolism, and downregulating inflammatory mediators with probiotics have promising potential.

Tumor necrosis factor and its potential role in insulin resistance and nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is a spectrum of hepatic pathology that resembles alcohol-induced fatty liver disease(AFLD), but which develops in individuals who are not heavy drinkers. In people, NAFLD is associated strongly with obesity,insulin resistance, and dysmetabolic syndrome, but the exact mechanisms that promote liver disease in this clinical context remain poorly understood. The proinflammatory cytokine, funor necrosis factor alpha is known to be a key mediator of AFLD. This article discusses clinical and experimental evidence that tumor necrosis factor plays a role in the pathogenesis of insulin resistance syndromes, including nonalcoholic fatty syndromes, including nonalcoholic fatty liver disease.

Non-alcoholic steatohepatitis in the Asia-Pacific region: future shock?

Clinicians in both the developed and also the newer industrial economies in the Asia-Pacific region will encounter non-alcoholic fatty liver disease (NAFLD) with increasing frequency. Although the region has been a significant contributor to the current state of knowledge, the spectrum of NAFLD, its severity and the potential for significant future morbidity and health costs are not widely recognized. Lifestyle changes, the epidemic of childhood and adult obesity and type 2 diabetes sweeping the Asia-Pacific represent the key substrates for the rising prevalence of NAFLD. Physicians in all disciplines need to be aware of clinical clues to the presence of NAFLD in the absence of other liver disease and in those with chronic viral hepatitis and they should be able to identify subsets at risk for liver-related morbidity. Given the scope of the problem, efforts should focus primarily on preventing or ameliorating the impact of risk factors; the key one is insulin resistance and its associates of diabetes and central obesity. Pharmacotherapy may play a role in selected individuals. A regional agenda for case definition, future study and public health initiatives is urgently required.

Steatosis and hepatitis C virus: mechanisms and significance for hepatic and extrahepatic disease

Nonalcoholic fatty liver disease (NAFLD) and hepatitis C virus (HCV)-related liver disease are common in the general population, but their concurrence is 2- to 3-fold higher than would be expected by chance alone. In patients with chronic HCV infection, steatosis is attributable to a variable combination of the mechanisms considered to play a role in the pathogenesis of NAFLD--insulin resistance in the obese and in the lean subject--along with a direct effect of HCV on hepatic lipid metabolism that leads to triglyceride accumulation through inhibition of export proteins that are required for very low density lipoprotein (VLDL) assembly and secretion. Accumulating evidence suggests that steatosis contributes to the progression of fibrosis in HCV-related disease in a pattern similar to that observed in NAFLD. Potential mechanisms of this effect include the increased sensitivity of steatotic livers to oxidative stress and cytokine-mediated injury. Steatosis-related hepatic insulin resistance may also play a role through the profibrogenic effects of the compensatory hyperinsulinemia and provides a potential explanation for the association between HCV and type 2 diabetes mellitus. Indeed, an appreciation of the importance of fat in HCV has recently led to trials of adjuvant therapy for HCV directed at steatosis-associated disease mechanisms, with encouraging results reported for various modalities, including weight loss and antioxidants. Future therapy should be aimed at exploiting the interactions of HCV with host insulin and lipid metabolism, particularly in nonresponders to standard antiviral schedules.

Non-alcoholic fatty liver disease: an emerging pathological spectrum

The spectrum of pathological lesions observed in non-alcoholic fatty liver disease (NAFLD) is wide and strongly resembles that of alcohol-induced liver disease. It ranges from fatty liver to steatohepatitis, progressive fibrosis and cirrhosis. Hepatocellular carcinoma is a possible complication of NAFLD, but whether it is related to frequently associated metabolic disorders (e.g., overweight, diabetes) or to underlying cirrhosis is unclear. This disease is the result of a multi-factorial process in which insulin resistance seems to play a major role in the initial accumulation of fat in the liver, whereas multiple causes of mitochondrial dysfunction and oxidative stress can induce the secondary occurrence of necroinflammatory lesions and fibrosis. Genetic factors might explain why only some patients with simple steatosis will develop steatohepatitis and fibrosis. Due to the increasing prevalence of obesity in Western countries, NAFLD will possibly be a public health problem and the liver disease of the future.

De novo non-alcoholic fatty liver disease following orthotopic liver transplantation

Non-alcoholic fatty liver disease (NAFLD) is an increasingly recognized clinico-pathologic entity typically associated with obesity, type II diabetes and hyperlipidemia. It has been noted to recur after orthotopic liver transplantation (OLT). We report four patients who developed de novo NAFLD within 3 months of OLT without the typical predisposing factors of diabetes mellitus or obesity. Three of the four patients underwent OLT for hepatitis C-related cirrhosis, and the other for alcoholic cirrhosis. Examination of the liver explants revealed no evidence of steatosis. No surreptitious alcohol use or a drug-induced process could be identified in these patients. Treatment of recurrent hepatitis C infection in one patient with interferon and ribavirin led to sustained suppression of the viral RNA to undetectable levels, but no improvement in histology or liver enzymes. All four patients had histologic evidence of preservation injury on the initial post-OLT biopsies, but the significance of this finding in relationship to the development of NAFLD is unknown. NAFLD can develop without any of the known predisposing conditions after transplantation, and this raises further questions about the pathogenesis of this condition.

Nonalcoholic steatohepatitis: summary of an AASLD Single Topic Conference

Fatty liver disease that develops in the absence of alcohol abuse is recognized increasingly as a major health burden. This report summarizes the presentations and discussions at a Single Topic Conference held September 20-22, 2002, and sponsored by the American Association for the Study of Liver Diseases. The conference focused on fatty liver disorders. Estimates based on imaging and autopsy studies suggest that about 20% to 30% of adults in the United States and other Western countries have excess fat accumulation in the liver. About 10% of these individuals, or fully 2% to 3% of adults, are estimated to meet current diagnostic criteria for nonalcoholic steatohepatitis (NASH). Sustained liver injury leads to progressive fibrosis and cirrhosis in a fraction, possibly up to one third, of those with NASH, and NASH may be a cause of cryptogenic cirrhosis. NASH is now a significant health issue for obese children as well, leading to cirrhosis in some. The diagnostic criteria for NASH continue to evolve and rely on the histologic findings of steatosis, hepatocellular injury (ballooning, Mallory bodies), and the pattern of fibrosis. Generally recognized indications for biopsy include establishing the diagnosis and staging of the injury, but strict guidelines do not exist. Liver enzymes are insensitive and cannot be used reliably to confirm the diagnosis or stage the extent of fibrosis. Older age, obesity, and diabetes are predictive of fibrosis. The pathogenesis of NASH is multifactorial. Insulin resistance may be an important factor in the accumulation of hepatocellular fat, whereas excess intracellular fatty acids, oxidant stress, adenosine triphosphate (ATP) depletion, and mitochondrial dysfunction may be important causes of hepatocellular injury in the steatotic liver. Efforts are underway to refine the role of insulin resistance in NASH and determine whether improving insulin sensitivity pharmacologically is an effective treatment. An altered lifestyle may be a more effective means of improving insulin sensitivity. The research agenda for the future includes establishing the role of insulin resistance and abnormal lipoprotein metabolism in NASH, determining the pathogenesis of cellular injury, defining predisposing genetic abnormalities, identifying better noninvasive predictors of disease, and defining effective therapy.

Clinical features and outcomes of juvenile dermatomyositis and other childhood onset myositis syndromes

The childhood myositis syndromes, primarily JDM, are relatively homogeneous diseases that have a good outcome in most cases, but are chronic, with poor outcomes, in a substantial number of cases. Because of the rarity of childhood myositis, and because there has not yet been a unified evidence-based approach to therapy, optimal treatment remains unknown. In clinic-based series the disease seems to be homogeneous but there are patients with rare clinical features, (e.g., cardiac, pulmonary, and neurologic disease), that impact prognosis. Racial, genetic, and other factors may lead to geographic variations in clinical presentations and outcomes, and perhaps further exploration of these influences will lead to a better understanding of the clinical features and outcomes seen in children. Our treatments are based on accumulated experience, but proper clinical trials have not been done. Ongoing registry studies, development of validated activity and damage assessment tools, large clinical trials, and continued investigation into the pathogenesis of the childhood myositis syndromes should lead to improved understanding and better treatments.

The liver in obesity and type 2 diabetes mellitus

Obesity and type 2 diabetes are associated strongly with NAFLD. It is not clear if one of these conditions causes the others, or if all are consequences of another process. Although NAFLD is known to occur in overly lean individuals, which indicates that excessive adiposity is not required for the development of NAFLD, the severities of insulin resistance and NAFLD tend to parallel each other, and the greatest prevalence of type 2 diabetes occurs in patients with NAFLD and cirrhosis. This observation suggests that insulin resistance and NAFLD may be related pathogenically. Experiments in mice demonstrate that insulin resistance and NAFLD result from a chronic inflammatory state that is characterized by increased levels of TNF alpha. The mechanisms that drive this chronic inflammation are unknown but might involve the oxidative stress that develops during fatty acid metabolism or when products from intestinal bacteria escape into the mesenteric blood to trigger a sustained hepatic inflammatory cytokine response in genetically susceptible individuals, promoting a positive feedback loop that reinforces insulin resistance and inflammation. This hypothesis is supported by some animal and human studies; however, more research is needed to evaluate this theory. Additional studies also are required to determine the benefits of treatments that interrupt this pathogenic cascade at various points. Preliminary work in animal and human studies suggests that diverse strategies that inhibit production of TNF alpha and improve insulin resistance also ameliorate NAFLD.

Other disease associations with non-alcoholic fatty liver disease (NAFLD)

Non-alcoholic fatty liver disease (NAFLD) is usually seen in middle-aged women with obesity, non-insulin-dependent diabetes mellitus and/or hyperlipidaemia. NAFLD has also been associated with other conditions. Surgical procedures to treat obesity such as jejunoileal bypass and gastroplasty as well as massive small bowel resection have been associated with NAFLD. Mechanisms such as rapid weight loss, certain nutritional deficiencies and bacterial overgrowth have been proposed. Other nutritional conditions such as extreme malnutrition and total parenteral nutrition can also cause NASH. This can be due to abnormal glucose and fat metabolism, deficiencies like carnitine, essential fatty acid and choline or, in the case of parenteral nutrition, excess of calories, glucose or lipids. Several drugs have also been implicated as well as some inborn errors of metabolism and, more rarely, other diseases.

Pathogenesis of steatohepatitis

Understanding the pathogenesis of non-alcoholic steatohepatitis has recently assumed great importance with the recognition that it has the potential to progress to fibrosis and cirrhosis. The 'two-hit' model of pathogenesis was proposed in 1998, with the first 'hit' - steatosis - increasing the sensitivity of the liver to the second 'hits' mediating liver injury. The main aim of this chapter is to review this model in the light of studies that have been published over the subsequent 4 years. Particular attention will be focused on the role of insulin resistance and recent advances in our understanding of the basic cellular mechanisms linking obesity and insulin resistance. Based on this information I will propose a modification of the two-hit model that places more emphasis on the role of free fatty acids. This model will provide the basis for further research and enable the rational design of treatment strategies.

Steatohepatitis in children

Steatohepatitis in children occurs in the childhood version of non-alcoholic fatty liver disease (NAFLD), as a result of hepatotoxicity and with certain genetic/metabolic diseases. Until recently, NAFLD was considered to be rare in children. It is now recognized as an important childhood liver disease, especially because childhood obesity is much more common. Children with NAFLD may present as young as 4 years old; males tend to predominate; fibrosis is often found on liver biopsy and cirrhosis has been reported. Treatment for childhood NAFLD currently consists of weight reduction plus regular aerobic exercise; vitamin E may be an effective adjunctive therapy. Drug hepatotoxicity and genetic/metabolic diseases that can cause fatty liver, such as Wilson's disease and cystic fibrosis, must be excluded since treatment is radically different. Other causes of chronic hepatitis, such as chronic viral hepatitis, must also be excluded. Multisystemic inherited diseases with hyperinsulinaemia plus insulin resistance may have NAFLD as hepatic involvement and should be identified.

Inherited metabolic diseases of the liver

Many inherited metabolic diseases affect the liver in neonates, children, or adults. The histopathologic changes are diverse and may be acute or chronic. They can be considered primary (when the injury is from the cytopathic effect of an accumulated metabolite) or secondary (e.g., an infection caused by an immune deficiency). All forms of liver disease are described: for example, intrahepatic cholestasis, neonatal hepatitis with giant-cell transformation, paucity of bile ducts, steatosis, steatohepatitis, necroinflammatory diseases (acute or chronic), fibrosis, cirrhosis, and neoplasms (benign or malignant). Familiarity with the morphologic changes is important in clinicopathologic correlation, diagnosis, and understanding of pathogenetic mechanisms.

Fatty liver and nonalcoholic steatohepatitis

Fatty liver is a relatively common incidental finding on imaging studies. Although generally a benign condition, fat in the liver can be troubling for clinicians because it can cause persistently elevated liver enzyme levels. The finding of fatty liver may also indicate the presence of nonalcoholic steatohepatitis (NASH). NASH is a histologic diagnosis applied to a constellation of liver biopsy findings that appear similar to alcoholic liver disease but are found in the absence of alcohol abuse. NASH is typically identified during the evaluation of elevated aminotransferase levels after exclusion of viral, metabolic, and other causes of liver disease. Obesity is a major risk factor; the role of diabetes is less certain, although evidence is accumulating that hyperinsulinism may play an important pathophysiologic role. About 15% to 40% of NASH patients develop hepatic fibrosis, a precursor to cirrhosis. Exactly how many patients with NASH progress to cirrhosis is unknown, but 1% to 2% of liver transplants are now performed because of a pretransplant diagnosis of NASH. Specific and effective treatments are needed but until the pathogenesis of this common liver disease is better understood, weight loss will remain the mainstay of treatment for obese patients.

Correlation of abdominal fat accumulation and liver steatosis: importance of ultrasonographic and anthropometric measurements

PURPOSE

This study has two objectives: (1) using ultrasound (US) as a tool for measuring subcutaneous (S) and intra-abdominal; preperitoneal (P) and visceral (V) fat thickness. (2) Assessing the relationship between selected anthropometrical variables and US-measured S, P and V fat also evaluating the contribution of abdominal fat accumulation in development of liver steatosis.

METHODS AND MATERIALS

Sixty-eight obese patients (aged 43.9+/-9.3 years) and 40 non-obese subjects (aged 34.03+/-9.0 years) were recruited to this study. Height, weight (W), waist (WC) and hip circumferences were measured. Body mass index (BMI) and waist to hip ratio (WHR) were calculated. A linear-array probe (7.5 MHz) was used to measure S and P. A convex-array probe (3.5 MHz) was used for measuring V and assessing liver fatty infiltration.

RESULTS

In 45 (66%) patients, there were diffuse liver fatty changes. Liver steatosis showed significant correlation with V (r=0.57), P (r=0.38) and S (r=0.37). It also correlated with W (r=0.52), BMI (r=0.6), WC (r=0.45) (P<0.0001). V positively correlated with BMI (r=0.62), W (r=0.55), WC (r=0.52) and WHR (r=0.33). P correlated with WC (r=0.29), WHR (r=0.36) and W (r=0.34), but not with BMI, height and age. A significant correlation was found between S and BMI (r=0.73), W (r=0.65), and WC (r=0.57) (P<0.0001).

CONCLUSION

Obese patients showed thicker S, P, and V. Liver steatosis correlates significantly with both anthropometrical data; BMI, WHR, WC, and W, and with abdominal V, P, and S fat. V fat can be used as a good predictor for the possibility of different metabolic disorders and liver disturbances as steastosis.

Nonalcoholic steatohepatitis

Nonalcoholic steatohepatitis (NASH) is a condition characterized by hepatomegaly, elevated serum aminotransferase levels, and a histologic picture similar to alcoholic hepatitis in the absence of alcohol abuse. Most patients with NASH are obese women, and many have diabetes mellitus, hypercholesterolemia, or hypertriglyceridemia. NASH has also been associated with a number of metabolic conditions, surgical procedures, and drug treatments. Most patients are asymptomatic. The most common sign of NASH is hepatomegaly. Stigmata of chronic liver disease are rare. Laboratory abnormalities include a 2-4-fold elevation of serum aminotransferase levels; other liver function test results are usually normal. Histologically, there is moderate to severe macrovesicular steatosis and lobular hepatitis with necrosis or ballooning degeneration and/or fibrosis. The pathogenesis of NASH is poorly understood, but lipid peroxidation and oxidative stress are the leading culprits. The natural history of NASH is unknown, but NASH seems to be a stable disease in most patients. Treatment of NASH is unproven, but weight reduction is recommended in obese patients. Small pilot studies of several drugs have shown promise, but large randomized clinical trials are awaited. Orthotopic liver transplantation is the treatment of choice for end-stage liver disease secondary to NASH.

Subcutaneous lipectomy causes a metabolic syndrome in hamsters

The insulin resistance syndrome X is related to excess intra-abdominal adipose tissue. With lipectomy of >50% of subcutaneous adipose tissue (SQAT) in nonhibernating, adult female Syrian hamsters on high-fat (HF; 50 calorie%) diet and measurements of oral glucose tolerance, oral [(14)C]oleic acid disposal, serum triglycerides, serum leptin, liver fat, perirenal (PR) adipose tissue cellularity, and body composition, we studied the role of SQAT. Sham-operated (S) animals on HF or low-fat (LF; 12.5 calorie%) diets served as controls. After 3 mo there was no visible regrowth of SQAT but HF diet led to similar levels of body weight and body fat in lipectomized and sham-operated animals. Lipectomized (L) animals had more intra-abdominal fat as a percentage of total body fat, higher insulinemic index, a strong trend toward increased liver fat content, and markedly elevated serum triglycerides compared with S-HF and S-LF. Liver and PR adipose tissue uptake of fatty acid were similar in L-HF and S-HF but reduced vs. S-LF, and were inversely correlated with liver fat content and insulin sums during the oral glucose tolerance test. In summary, lipectomy of SQAT led to compensatory fat accumulation implying regulation of total body fat mass. In conjunction with HF diet these lipectomized hamsters developed a metabolic syndrome with significant hypertriglyceridemia, relative increase in intra-abdominal fat, and insulin resistance. We propose that SQAT, via disposal and storage of excess ingested energy, acts as a metabolic sink and protects against the metabolic syndrome of obesity.

Nonalcoholic steatohepatitis and cryptogenic cirrhosis within kindreds

PURPOSE

Familial forms of cryptogenic cirrhosis have been described. We have cared for families in which several members were afflicted with cryptogenic cirrhosis as well as the more recently recognized entity of nonalcoholic steatohepatitis. To examine the familial patterns of these disorders, we reviewed patients with nonalcoholic steatohepatitis, with and without cirrhosis, or cryptogenic cirrhosis to assess how frequently their relatives were afflicted with these disorders.

SUBJECTS AND METHODS

Eighteen members of eight kindreds containing 2 or more afflicted members were studied. Diagnoses were based on histology in all but 3 patients (2 elderly women with liver atrophy and severe cirrhotic ascites diagnosed clinically with cryptogenic cirrhosis and 1 adult man with abnormal serum aminotransferase levels and hepatomegaly that was diagnosed as fatty liver by ultrasound). Other forms of liver disease were excluded by extensive serologic testing.

RESULTS

There were 8 index patients (1 man, 7 women; 2 with cryptogenic cirrhosis, 4 with nonalcoholic steatohepatitis with cirrhosis, and 2 with nonalcoholic steatohepatitis without cirrhosis) and 10 relatives (4 men, 6 women; 2 with cryptogenic cirrhosis and 8 with nonalcoholic steatohepatitis). Nonalcoholic steatohepatitis and nonalcoholic steatohepatitis with cirrhosis coexisted within four kindreds, one of which also had an afflicted member with cryptogenic cirrhosis. Nonalcoholic steatohepatitis and cryptogenic cirrhosis coexisted within three additional kindreds. Patterns of afflicted patients included mother-daughter, sister-sister, sister-brother, father-daughter, and male-female cousins. Fifteen (83%) of the 18 subjects were obese, and 11 (61%) had type 2 diabetes mellitus.

CONCLUSIONS

The coexistence of nonalcoholic steatohepatitis with and without cirrhosis and cryptogenic cirrhosis within these kindreds suggests a common pathogenesis and possible genetic risk. These disorders were frequently but not invariably associated with female sex, obesity, and type 2 diabetes.

Mitochondrial abnormalities in non-alcoholic steatohepatitis

BACKGROUND/AIMS

We assessed mitochondrial morphology by electron microscopy and the prevalence of a mitochondrial gene deletion in patients with non-alcoholic steatohepatitis (NASH), alcohol-related liver disease and non-fatty liver diseases. Respiratory chain function using a cytoplasmic hybrid (cybrid) assay was further studied in NASH patients and healthy controls.

METHODS

Electron microscopy was performed in 26 specimens. Fifteen patients were studied by polymerase chain reaction to detect a 520-bp deletion product of the mitochondrial genome (dmtDNA). Cybrids were created by fusion of platelets with anaerobic neuroblastoma cells in six NASH patients and 12 controls.

RESULTS

Eight of ten NASH, one of seven alcoholics and two of nine other patients had linear crystalline inclusions in megamitochondria (p<0.05). Three of five patients with alcohol-related liver disease had dmtDNA compared to one of five NASH patients and one of five non-steatohepatitis controls. Cybrid respiratory chain function in platelets was not different from that of controls.

CONCLUSIONS

Respiratory chain dysfunction, if present in NASH, is not expressed in platelet-derived mitochondria. In contrast to alcohol-related liver disease with active drinking, NASH patients do not commonly express the 5-kb mitochondrial DNA gene deletion in liver tissue. As previously described in early alcohol-related liver disease, crystalline inclusions of unknown composition are seen in hepatic mitochondria in NASH. Their presence suggests either an adaptive process or mitochondrial injury.

Mitochondrial abnormalities in non-alcoholic steatohepatitis

BACKGROUND/AIMS

We assessed mitochondrial morphology by electron microscopy and the prevalence of a mitochondrial gene deletion in patients with non-alcoholic steatohepatitis (NASH), alcohol-related liver disease and non-fatty liver diseases. Respiratory chain function using a cytoplasmic hybrid (cybrid) assay was further studied in NASH patients and healthy controls.

METHODS

Electron microscopy was performed in 26 specimens. Fifteen patients were studied by polymerase chain reaction to detect a 520-bp deletion product of the mitochondrial genome (dmtDNA). Cybrids were created by fusion of platelets with anaerobic neuroblastoma cells in six NASH patients and 12 controls.

RESULTS

Eight of ten NASH, one of seven alcoholics and two of nine other patients had linear crystalline inclusions in megamitochondria (p<0.05). Three of five patients with alcohol-related liver disease had dmtDNA compared to one of five NASH patients and one of five non-steatohepatitis controls. Cybrid respiratory chain function in platelets was not different from that of controls.

CONCLUSIONS

Respiratory chain dysfunction, if present in NASH, is not expressed in platelet-derived mitochondria. In contrast to alcohol-related liver disease with active drinking, NASH patients do not commonly express the 5-kb mitochondrial DNA gene deletion in liver tissue. As previously described in early alcohol-related liver disease, crystalline inclusions of unknown composition are seen in hepatic mitochondria in NASH. Their presence suggests either an adaptive process or mitochondrial injury.

Nonalcoholic steatohepatitis

NASH is an important form of chronic liver disease that is increasingly recognized. The diagnosis is secured by biopsy findings with similarities to alcoholic hepatitis in a patient with a confirmed history of abstinence. Obesity is a major risk factor, but the disease also occurs in the nonobese. In 20% to 40% of patients the disease can progress to various stages of fibrosis and ultimately cause cirrhosis and death from end-stage liver disease. For this reason, recognition of NASH is important, and establishing the diagnosis provides a further impetus for performing a liver biopsy as part of the evaluation of unexplained liver abnormalities. The mainstay of treatment is weight reduction in the obese. For those individuals who are not obese, continued observation is the only option currently available. Patients who develop decompensated cirrhosis should be considered for liver transplantation unless advanced age or other underlying medical illnesses are a problem. With the increasing knowledge about the pathophysiology of hepatic steatosis, it is hoped that better diagnostic tests for specific causes of NASH will be available and lead to efficacious therapy.

Review: nonalcoholic steatohepatitis

Nonalcoholic steatohepatitis (NASH) is a reasonably well-defined clinicopathological entity; it has been reported more commonly in women than in men or children of both sexes and it appears to be most closely associated with obesity, diabetes mellitus and related abnormalities, such as hyperlipidaemia and hyperglycaemia. However, the association with female gender, obesity and diabetes may not be as close as suggested by the literature and an underlying condition cannot be discerned in all cases. The natural history of the disease is poorly understood; the associated biopsy features span a wide spectrum, reaching from uncomplicated, clinically non-progressive fatty liver (not NASH in a strict sense) to a slowly progressive fatty liver with inflammation and fibrosis, to steatohepatitis with submassive hepatic necrosis, which has a subfulminant course and is often fatal. Non-progressive fatty liver appears to be very common but is of little clinical importance. The slowly progressive form of the disease represents NASH as encountered by most clinicians and pathologists. It is a common liver disease in current practice; patients may present with cirrhosis and even HCC arising from steatohepatitic cirrhosis. Subfulminant NASH has become exceedingly rare because many clinicians are now aware of the hazards of sudden weight loss, particularly in morbidly obese patients. Treatment options for NASH are still limited. The promotion of gradual weight loss in obese patients is the most widely recommended therapy but, unfortunately, this is very difficult to achieve. Avoidance of precipitous weight loss and careful control of diabetes mellitus are important and undisputed parts of patient management. Administration of UDCA as a treatment of NASH is still under study; it may be effective in some patients. The treatment of established steatohepatitic cirrhosis does not differ substantially from that of other types of cirrhosis and includes orthotopic liver transplantation.

Partial lipodystrophy associated with juvenile dermatomyositis: report of two cases

A 27-year-old woman and a 13-year-old girl diagnosed with juvenile dermatomyositis in childhood developed clinical findings of partial lipodystrophy 10 years after diagnosis. Exhaustive clinical and laboratory examinations showed an association with other abnormalities: hypertrichosis, steatohepatitis, and an abnormal insulin response to the glucose loading test in the first patient. Hypertrichosis, steatohepatitis, insulin-resistant diabetes mellitus, and acanthosis nigricans were observed in the second patient. Renal function was normal in both patients. Although a localized form of lipodystrophy has been reported associated with connective tissue disease (connective tissue lipoatrophy), the partial form has been infrequently described in association with juvenile dermatomyositis.

Nonalcoholic steatohepatitis

NASH is a form of chronic liver disease that is defined by biopsy findings and has the appearance of alcoholic hepatitis. Although this disease was once thought to be a problem of women, diabetics, and the obese, more recent studies have identified a significant proportion of patients who do not fit these risk factors. In a fraction of patients, the disease can progress to various stages of fibrosis leading ultimately to cirrhosis and death from end-stage liver disease. For this reason, recognition of NASH is important and provides a further impetus for performing a liver biopsy as part of the evaluation of unexplained liver biochemical abnormalities. The mainstay of treatment is weight reduction in the obese. For those individuals who are not obese, continued observation is the only available option at this point. With increasing knowledge about the pathophysiology of hepatic steatosis, perhaps more specific diagnostic tests for the cause of the disease in specific patients will be available and will guide appropriate therapy.

Body fat topography as an independent predictor of fatty liver

Abdominal (truncal) fat distribution reflected by an elevated waist to hip ratio (WHR) predicts metabolic abnormalities such as diabetes and dyslipidemia as well as hypertension and stroke, all of which are associated with obesity. The pathogenesis is not known, although elevated splanchnic serum free fatty acid levels and reduced hepatic insulin clearance have been implicated. WHR and body fat (BF) by 40K-counting and 3H2O were measured before liver biopsy during antiobesity surgery in 68 severely obese women (body mass index [BMI], 48.9 +/- 1.1 SEM) and 15 men (BMI, 49.0 +/- 3.1) without histories of liver disease, diabetes, or hepatotoxic exposure. Biopsies were graded for fat content semiquantitatively (0 to 4+) by the hepatologist who was blinded to the patients' clinical characteristics. All 15 men had fatty infiltration (score, 2.5 +/- 0.3 v 1.4 +/- 0.1 in women; P < .001). The correlation between WHR and liver fat was .44 (P < .0005), while BF (-.16), weight (.15), or BMI (.04) did not correlate significantly with steatosis (all NS). As expected, percentage body fat (BF%) was greater in women than in men (40.3 +/- 0.8 kg v 33.9 +/- 2.0, P < .007), and accordingly liver fat was inversely related to BF% (r = -.32, P < .002). Steatosis was significantly greater in 14 men (2.5 +/- 0.3) than in 20 women (1.7 +/- 0.3, P < .04) matched for BF%. In multiple regression analysis R2 = .49, P < .0001), WHR and sex accounted for the variance in liver fat content without any further contribution from weight, BMI, BF, or BF%.(ABSTRACT TRUNCATED AT 250 WORDS)

The natural history of nonalcoholic steatohepatitis: a follow-up study of forty-two patients for up to 21 years

Forty-two patients with nonalcoholic steatohepatitis were followed for a median of 4.5 yr (range = 1.5 to 21.5 yr). Except for two patients with lipodystrophy, all were obese; 35 of 42 were women, 26 of 32 were hyperlipidemic and 15 were hyperglycemic. Upper abdominal pain was the most common reason for presentation. Initial liver biopsy specimens showed the presence of macrovesicular fatty infiltration, lobular (acinar) inflammation, apoptosis, Mallory bodies (in four cases) and fibrosis (in 18 cases). Cirrhosis was present at initial diagnosis in one subject and in another two subjects liver biopsy showed marked fibrosis with disturbed architecture. Serial liver biopsy specimens revealed minimal or no apparent progression of the disorder in most of the patients, in keeping with their benign clinical course. However, one patient showed progression from fibrosis to cirrhosis during the 5-yr observation period, and in the patients with extensive fibrosis the liver disease evolved from one of active inflammation to one of inactive cirrhosis without fat or inflammation. The patient with cirrhosis later died of hepatocellular carcinoma. The severity or type of hepatic change did not correlate with the degree of obesity, hyperlipidemia or hyperglycemia. However, in individual patients, poorly controlled diabetes and rapid weight loss preceded the onset of steatohepatitis. We conclude that nonalcoholic steatohepatitis is a cause of hepatic inflammation histologically resembling that of alcohol-induced liver disease but usually slowly progressive and of low-grade severity. However, the disorder may ultimately result in cirrhosis. Nonalcoholic steatohepatitis should be distinguished from alcoholic steatohepatitis and recognized as a further cause of "cryptogenic cirrhosis."