Accuracy and reproducibility of transient elastography for the diagnosis of fibrosis in pediatric nonalcoholic steatohepatitis

Hyaluronic acid predicts hepatic fibrosis in children with nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease in children and adolescents, and it may progress to liver fibrosis and cirrhosis. Liver biopsy, which is the recognized gold standard for the diagnosis of hepatic fibrosis, is invasive. Thus, there has been increasing interest in the development of noninvasive markers. Hyaluronic acid (HA) has been shown to be a good marker of liver fibrosis in adults. In the current study, we evaluated the association of HA with liver fibrosis in 100 consecutive children with biopsy-proven NAFLD. In all, 65% of the children had liver fibrosis. Using proportional-odds ordinal logistic regression, we found that values of HA ≥ 1200 ng/mL made the absence of fibrosis (F0) unlikely (7%, 95% confidence interval [CI]: 1% to 14%), whereas values of HA ≥ 2100 ng/mL made F2, F3, or F4 fibrosis likely (89%, 95% CI: 75% to 100%). Our study shows that HA is a predictor of fibrosis in children with NAFLD followed at a tertiary care center. Additional studies are needed to test whether HA can be employed to predict liver fibrosis in pediatric populations with similar and lower prevalence of liver fibrosis.

Pediatric nonalcoholic fatty liver disease: A clinical and laboratory challenge

The true prevalence of pediatric nonalcoholic fatty liver disease (NAFLD) is unknown. Challenges in determining the population prevalence of NAFLD include the type of test (and the reference intervals used to define normal and abnormal), the type of population (general population, hospital series), the demographic characteristics of the population sampled, and the nature of the study design. The natural history of pediatric NAFLD remains uncertain. The issue of when to perform a liver biopsy in children with suspected NAFLD remains controversial. Children with NAFLD but normal alanine aminotransferase are rarely investigated. However, evidence of alterations in glucose metabolism parameters should prompt a better understanding of the natural history of pediatric NAFLD not only in terms of the progression of liver disease but also regarding its potential relationship with other health outcomes such as type 2 diabetes mellitus and cardiovascular disease. This evidence could make liver biopsy mandatory in the majority of cases at risk of progressive and severe hepatic and extrahepatic disease. This conclusion, however, raises the question of the feasibility of liver biopsy assessment in an extremely large at risk population, and of the cost/effectiveness of this policy. There is a considerable, continuous interest in reliable, noninvasive alternatives that will allow the prognosis of pediatric NAFLD to be followed in large community or population-based studies.

Transient elastography in patients with cystic fibrosis

BACKGROUND

Hepatic involvement is frequent in patients with cystic fibrosis (CF), with focal biliary cirrhosis being the pathognomonic hepatic manifestation. In around one-quarter of CF patients, it results in CF-associated liver disease (CFLD). This occurs as a relatively early complication with the majority of patients presenting in childhood or their early teens. However, a normal US does not preclude significant liver fibrosis and liver biopsy is an invasive procedure that is hampered by potential sampling errors. Transient elastography (TE) (Fibroscan) is a non-invasive, user-friendly and quick technique that provides an objective and reproducible measure of liver stiffness. This is accomplished with a device using an US probe mounted in the axis of a vibrator. Vibrations are transmitted by the transducer, inducing an electronic shear wave that propagates through the underlying tissue.

OBJECTIVES

We aimed to prospectively compare TE and transabdominal US scanning in children and adults attending a CF clinic.

MATERIALS AND METHODS

A total of 134 consecutive patients with documented CF were prospectively studied. In each case, transient elastography measurement was performed immediately after the routine annual US evaluation of the liver. Sonographic appearance of the liver was classified from 1 to 5. Ten validated TE measurements were performed in each patient with the result expressed in kilopascals (kPa). The median value was considered representative of the elastic modulus of the liver.

RESULTS

Measurements were performed in 59 CF adults, 75 CF children and 31 control children. There was no relationship between age and liver stiffness in either the control group or CF patients. Elasticity values of controls, CF pancreatic sufficient (PS) patients and pancreatic insufficient (PI) CF patients with a US score <3 were comparable and significantly lower than in CF patients with a US score > or = 3 (all PI) (P < 0.002). Median elasticity in CF patients was significantly higher in males (4.7 kPa) than in females (3.9 kPa) (P = 0.0013).

CONCLUSION

Considering the limitations of US and the low risk-benefit rate of liver biopsy in most CF patients, this preliminary study suggests that TE is an attractive non-invasive way to assess and follow-up liver disease in these patients.

Nonalcoholic fatty liver disease in children

PURPOSE OF REVIEW

The intent of this review is to provide a concise overview of all recent acquisitions in terms of therapies and early noninvasive diagnostic approaches for nonalcoholic fatty liver disease (NAFLD) in children.

RECENT FINDINGS

NAFLD is increasingly being diagnosed in children. If undiscovered and if certain risks are present (i.e. obesity), nonalcoholic steatohepatitis, the most severe form of NAFLD, may silently progress to cirrhosis, hepatocarcinoma and liver-related death in adulthood. Current therapies include approaches for reducing the incidence of risk factors (i.e. weight reduction), drugs targeting the major molecular mechanisms thought essential in the pathogenesis of the disease (insulin resistance and oxidative stress) or both, but other novel treatments are under investigation.

SUMMARY

Although weight reduction, achieved through a combination of diet and exercise, makes it possible to modify the natural course of simple steatosis, the addition of adequate drugs might also provide a therapeutic action on nonalcoholic steatohepatitis. Moreover, preventive strategies and the design and translation into clinical practice of indices that integrate noninvasive diagnostic tools and serum biomarkers might be a winning approach for improving management of paediatric NAFLD/nonalcoholic steatohepatitis in the coming years.

Paediatric cholestatic liver disease: Diagnosis, assessment of disease progression and mechanisms of fibrogenesis

Cholestatic liver disease causes significant morbidity and mortality in children. The diagnosis and management of these diseases can be complicated by an inability to detect early stages of fibrosis and a lack of adequate interventional therapy. There is no single gold standard test that accurately reflects the presence of liver disease, or that can be used to monitor fibrosis progression, particularly in conditions such as cystic fibrosis. This has lead to controversy over how suspected liver disease in children is detected and diagnosed. This review discusses the challenges in using commonly available methods to diagnose hepatic fibrosis and monitor disease progression in children with cholestatic liver disease. In addition, the review examines the mechanisms hypothesised to be involved in the development of hepatic fibrogenesis in paediatric cholestatic liver injury which may ultimately aid in identifying new modalities to assist in both disease detection and therapeutic intervention.

Nonalcoholic fatty liver disease/nonalcoholic steatohepatitis: histological diagnostic criteria and scoring systems

Nonalcoholic fatty liver disease (NAFLD) is recognized as the most common cause of chronic liver disease in western countries. NAFLD is etiologically associated with systemic and hepatic insulin resistance and is considered by many as the hepatic manifestation of the metabolic syndrome. NAFLD has a wide histological spectrum ranging from 'simple' steatosis to nonalcoholic steatohepatitis (NASH), which may progress to cirrhosis. Hepatocellular carcinoma may occur in NASH-related cirrhosis. The diagnosis of NAFLD/NASH is based on clinico-pathological criteria. Currently available noninvasive tests for the diagnosis of NASH lack specificity and sensitivity, so liver biopsy, despite its limitations, still remains the 'golden standard' for confirming or excluding NASH in a patient with chronically-elevated liver enzymes and image-detected steatosis. This review examines the currently used criteria for the histopathological diagnosis of NAFLD/NASH in adults and children and the relevant histological scoring systems.

Pathology of nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is a significant complication of obesity and is recognized as the hepatic manifestation of the metabolic syndrome. The process occurs in adults and children and is characterized by the presence of increased amounts of fat in the liver (steatosis). With inflammation, cell death and scarring (fibrosis), the process may result in end-stage liver disease, or be a precursor for hepatocellular carcinoma. Excess hepatic fat is now recognized as an independent marker for increased cardiovascular risk. Even though imaging studies and laboratory-based tests are accurate at detecting significant steatosis and/or advanced fibrosis, respectively, the diagnosis and characterization of NAFLD ultimately depend on histopathologic evaluation, as the parenchymal alterations that comprise the spectrum of injury in NAFLD include patterns as well as specific lesions. Histologic findings in children may differ from those in adults. In this Review, the histologic features that are diagnostic and discriminatory between steatosis and steatohepatitis, the significance of the distinction between steatosis and steatohepatitis, the types and locations of fibrosis, and the histologic variances between adult and pediatric NAFLD are discussed. Clinical advantages as well as potential drawbacks of liver biopsy are presented. Current pathophysiologic concepts relevant to histologic findings are discussed.

Pitfalls of liver stiffness measurement: a 5-year prospective study of 13,369 examinations

Liver stiffness measurement (LSM) based on transient elastography (TE, FibroScan) is gaining in popularity for noninvasive assessment of liver fibrosis. However, LSM has limitations, which have not yet been thoroughly evaluated. We prospectively investigated the frequency and determinants of LSM failure and unreliable results over a 5-year period, based on 13,369 examinations (134,239 shots). LSM failure was defined as zero valid shots, and unreliable examinations were defined as fewer than 10 valid shots, an interquartile range (IQR)/LSM greater than 30%, or a success rate less than 60%. LSM failure occurred in 3.1% of all examinations (4% at first examination [n = 7261]) and was independently associated at first examination with body mass index (BMI) greater than 30 kg/m(2) (odds ratio [OR], 7.5; 95% confidence interval [CI], 5.6-10.2; P = 0.0001), operator experience fewer than 500 examinations (OR 2.5 [1.6-4.0]; P = 0.0001); age greater than 52 years (OR 2.3 [1.6-3.2]; P = 0.0001), and type 2 diabetes (OR 1.6 [1.1-2.2]; P = 0.009). Unreliable results were obtained in a further 15.8% of cases (17% at first examination) and were independently associated at first examination with BMI greater than 30 kg/m(2) (OR 3.3 [2.8-4.0]; P = 0.0001), operator experience fewer than 500 examinations (OR 3.1 [2.4-3.9]; P = 0.0001), age greater than 52 years (OR 1.8 [1.6-2.1]; P = 0.0001), female sex (OR 1.4 [1.2-1.6], P = 0.0001), hypertension (OR 1.3 [1.1-1.5]; P = 0.003), and type 2 diabetes (OR 1.2 [1.0-1.5]; P = 0.05). When metabolic syndrome and waist circumference were taken into account in a subgroup of 2835 patients, waist circumference was the most important determinant of LSM failure and unreliable results.

CONCLUSION

In our experience, liver stiffness measurements are uninterpretable in nearly one in five cases. The principal reasons are obesity, particularly increased waist circumference, and limited operator experience. These results emphasize the need for adequate operator training and for technological improvements in specific patient subpopulations.

Diagnosis of fibrosis and cirrhosis using liver stiffness measurement in nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is one of the most common liver diseases in affluent countries. Accurate noninvasive tests for liver injury are urgently needed. The aim of this study was to evaluate the accuracy of transient elastography for the diagnosis of fibrosis and cirrhosis in patients with NAFLD and to study factors associated with discordance between transient elastography and histology. Two hundred forty-six consecutive patients from two ethnic groups had successful liver stiffness measurement and satisfactory liver biopsy specimens. The area under the receiver-operating characteristics curve (AUROC) of transient elastography for F3 or higher and F4 disease was 0.93 and 0.95, respectively, and was significantly higher than that of the aspartate aminotransferase-to-alanine aminotransferase ratio, aspartate aminotransferase-to-platelet ratio index, FIB-4, BARD, and NAFLD fibrosis scores (AUROC ranged from 0.62 to 0.81, P < 0.05 for all comparisons). At a cutoff value of 7.9 kPa, the sensitivity, specificity, and positive and negative predictive values for F3 or greater disease were 91%, 75%, 52%, and 97%, respectively. Liver stiffness was not affected by hepatic steatosis, necroinflammation, or body mass index. Discordance of at least two stages between transient elastography and histology was observed in 33 (13.4%) patients. By multivariate analysis, liver biopsy length less than 20 mm and F0-2 disease were associated with discordance.

CONCLUSION

Transient elastography is accurate in most NAFLD patients. Unsatisfactory liver biopsy specimens rather than transient elastography technique account for most cases of discordance. With high negative predictive value and modest positive predictive value, transient elastography is useful as a screening test to exclude advanced fibrosis. Liver biopsy may be considered in NAFLD patients with liver stiffness of at least 7.9 kPa.

Fatty liver disease in children: eat now pay later

INTRODUCTION

With the recent epidemic in childhood obesity, nonalcoholic fatty liver disease (NAFLD) has become an emerging problem and a common cause of chronic liver disease in children.

METHODS

In this review, the most recent insights on the pathogenesis, diagnosis, natural history, and treatment of NAFLD in children are discussed.

Transient elastography for the assessment of liver fibrosis in patients with chronic viral hepatitis: the missing tool?

The fibrogenic evolution of chronic viral hepatitis B and C towards cirrhosis represents a key issue in clinical Hepatology whose monitoring still relies on liver biopsy and consequent histopathological staging. In the last decade, non-invasive methodologies have been proposed to predict the presence of fibrosis in chronic liver disease. Most of these methods are based on algorithms, including biochemical parameters, which have demonstrated an acceptable diagnostic accuracy towards the two extremities of the fibrogenetic process. The introduction of transient elastography has represented a further advancement in clinical Hepatology and it seems that the combination of different non-invasive methodologies will provide an improvement in the clinical management of disease progression in viral chronic hepatitis. Studies, conducted especially in chronic viral hepatitis C, suggest that transient elastography is a useful technique for the detection of severe fibrosis-cirrhosis and for the exclusion of significant fibrosis (>or=F2), that could be employed as "diagnostic discriminator" for establishing clinical priorities and reducing the number of liver biopsies. This review article will focus on the clinical utility of this novel methodology for the assessment of liver fibrosis in chronic viral hepatitis and will highlight potential further advantages.

Predictors of steatohepatitis and advanced fibrosis in non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease is the most common cause of chronic liver disease in the United States. The development of non-alcoholic steatohepatitis increases the risk for cirrhosis and its complications. The gold standard for diagnosis is liver biopsy, the costs and risks of which make it impractical. Some demographic factors, blood tests, and imaging studies can be used to predict a higher risk of steatohepatitis or advanced fibrosis, but are of limited sensitivity and specificity. More accurate predictors and scoring systems would allow identifying who would benefit most from liver biopsy and monitor disease progression and response to therapy.

Cytokeratin-18 fragment levels as noninvasive biomarkers for nonalcoholic steatohepatitis: a multicenter validation study

Liver biopsy remains the gold standard for diagnosing nonalcoholic steatohepatitis (NASH). We have recently demonstrated that plasma cytokeratin 18 (CK-18) fragment levels correlate with the magnitude of hepatocyte apoptosis and independently predict the presence of NASH. The goal of this study was to validate the use of this biomarker for NASH diagnosis. The study was an ancillary study of the NASH Clinical Research Network (NASH CRN). Our cohort consisted of 139 patients with biopsy-proven nonalcoholic fatty liver disease (NAFLD) from eight CRN participant centers across the United States and 150 age-matched healthy controls. CK-18 fragments were measured using a specific enzyme-linked immunosorbent assay. Histology was assessed centrally by study pathologists. CK-18 fragments were markedly increased in patients with NASH versus those without NASH and borderline diagnosis (median [25th, 75th percentile], 335 [196, 511], 194 [151, 270], 200 [148, 284], respectively; P < 0.001). Moreover, the odds of having fibrosis on liver biopsy increased with increasing plasma CK-18 fragment levels (P < 0.001). On multivariate regression analysis, CK-18 fragments remained an independent predictor of NASH after adjusting for variables associated with CK-18 fragments or NASH on univariate analysis (fibrosis, alanine aminotransferase, aspartate aminotransferase, age, biopsy length). The area under the receiver operating characteristic curve for NASH diagnosis was estimated to be 0.83 (0.75, 0.91).

CONCLUSION

Determination of CK-18 fragments in the blood predicts histological NASH and severity of disease in a large, diverse population of patients with biopsy-proven NAFLD, supporting the potential usefulness of this test in clinical practice.

Advances in pediatric nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) has emerged as the leading cause of chronic liver disease in children and adolescents in the United States. A two- to three-fold rise in the rates of obesity and overweight in children over the last two decades is probably responsible for the NAFLD epidemic. Emerging data suggest that children with nonalcoholic steatohepatitis (NASH) progress to cirrhosis, which may ultimately increase liver-related mortality. More worrisome is the recognition that cardiovascular risk and morbidity in children and adolescents are associated with fatty liver. Pediatric fatty liver disease often displays a histologic pattern distinct from that found in adults. Liver biopsy remains the gold standard for diagnosis of NASH. Noninvasive biomarkers are needed to identify individuals with progressive liver injury. Targeted therapies to improve liver histology and metabolic abnormalities associated with fatty liver are needed. Currently, randomized-controlled trials are underway in the pediatric population to define pharmacologic therapy for NAFLD.

CONCLUSION

Public health awareness and intervention are needed to promote healthy diet, exercise, and lifestyle modifications to prevent and reduce the burden of disease in the community.

Nonalcoholic steatohepatitis in children: a multicenter clinicopathological study

Nonalcoholic fatty liver disease (NAFLD) may have distinct histological features in children and adults, but to date limited data are available on the spectrum and significance of histological lesions in pediatric patients. We conducted a multicenter study of children with well-characterized, biopsy-proven NAFLD to (1) assess the presence and significance of a constellation of histological lesions and (2) identify clinical and laboratory predictors of disease severity. One hundred thirty children with NAFLD seen from 1995 to 2007 in five centers in the United States and Canada were studied. Clinical and laboratory data were collected. Slides stained with hematoxylin-eosin and trichrome were evaluated by two liver pathologists. The NAFLD activity score (NAS) and the pattern of liver injury (type 1 or adult versus type 2 or pediatric nonalcoholic steatohepatitis [NASH]) were recorded. Fibrosis was staged using a published 7-point scale. The median age was 12 years (range, 4-18 years); 63% were boys, and 52% were Caucasian. Fibrosis was present in 87% of patients; of these, stage 3 (bridging fibrosis) was present in 20%. No patient had cirrhosis. The median NAS was 4. Overlapping features of both type 1 (adult pattern) and type 2 (pediatric pattern) NASH were found in 82% of patients. Compared with patients with no or mild fibrosis, those with significant fibrosis were more likely to have higher lobular and portal inflammation scores (P < 0.01), perisinusoidal fibrosis (P < 0.001), and NAS > or =5 (P < 0.005). Serum aspartate aminotransferase levels were the only clinical or laboratory data that independently predicted severity of fibrosis (P = 0.003).

CONCLUSION

Our results highlight the limitations of published proposals to classify pediatric NAFLD, and identified histological lesions associated with progressive disease.

Non-invasive liver elastography (Fibroscan) for detection of cystic fibrosis-associated liver disease

BACKGROUND

Cystic fibrosis-associated liver disease (CFLD) is the second cause of mortality in CF. The prevalence is estimated to be 26-45%, but sensitive diagnostic tools are lacking. We investigated whether non-invasive liver elastography (Fibroscan) could serve as a screening tool.

METHODS

Fibroscan measurements were performed in 66 CF patients. Age-specific cutoff values were determined in a control population (n=59). The measurements were compared to clinical data, bi-yearly biochemistry and ultrasound.

RESULTS

Fibroscan was easy to perform in this patient population. There were 14 patients (21%) with abnormal liver stiffness measurements. Liver stiffness was significantly increased in patients with clinical CFLD (11.2 kPa versus 5.1 kPa), biochemical CFLD (7.4 kPa versus 5.4 kPa) or ultrasonographical CFLD (8.2 versus 4.3 kPa) (p<0.02 for all).

CONCLUSIONS

Fibroscan is an objective measure and is easy to perform in CF patients, even in children and could provide a valuable tool to detect, and quantify CFLD.

Is juvenile liver biopsy unsafe? Putting an end to a common misapprehension

BACKGROUND

Percutaneous needle biopsy of the liver is the most common procedure used in clinical hepatology for histopathological examination and assessment of liver disease, and remains the cornerstone in the evaluation and management of parenchymal liver diseases. Liver biopsy is generally regarded as a safe procedure, but mortality rates up to 1:10,000 have been reported. In 2003, our group showed that routine use of US as a guide to liver biopsy reduces the rate of complications and provides a higher diagnostic yield.

OBJECTIVE

To report our experience of US-guided liver biopsy in children.

MATERIALS AND METHODS

We retrospectively reviewed all 421 liver biopsies performed in our department from October 2003 to December 2008. All samples had been obtained by the US-guided technique. All patients had a liver US examination performed prior to the procedure by the same radiologist performing the biopsy.

RESULTS

US guidance allowed constant visualization of the needle leading to appropriate tissue sampling in all 421 children (including 221 obese children), and in 79% of children with only one pass. Pain in the right upper quadrant after liver biopsy was experienced by 36% of patients.

CONCLUSION

US-guided percutaneous biopsy of the liver in children, performed in a specialized tertiary care paediatric centre by experienced and skilled physicians, can be considered safe and effective.

Diagnosis and treatment of pediatric nonalcoholic steatohepatitis and the implications for bariatric surgery

This review focuses on the diagnosis, risk factors, prevalence, pathogenesis and treatment of pediatric nonalcoholic steatohepatitis (NASH). NASH is a progressive form of nonalcoholic fatty liver disease (NAFLD), the most common cause of chronic liver disease in children. The factors that account for differences between children with NASH and children with milder forms of NAFLD are unclear. The diagnosis of NASH requires interpretation of liver histology because no noninvasive markers predict the presence or severity of NASH. There is no proven treatment for NASH. Several clinical trials for NAFLD are in progress; however, clinical trials focusing on NASH are needed. Heightened physician awareness of NAFLD, NASH, and associated risk factors is important to identify and treat affected children.

The metabolic syndrome and nonalcoholic fatty liver disease in children

PURPOSE OF REVIEW

Nonalcoholic fatty liver disease (NAFLD) is increasingly prevalent in pediatric-age individuals, in parallel with increasing obesity, and can lead to liver inflammation, fibrosis, and even cirrhosis. NAFLD appears tightly linked with features of the metabolic syndrome (MetS). This review aims to reconsider the clinical presentation, laboratory and pathologic assessment, and treatment of NAFLD, with a focus on its relationship with the MetS.

RECENT FINDINGS

NAFLD occurs with a high prevalence and severity in obese, insulin-resistant adolescents, especially Hispanic males. Pediatric NAFLD may improve with lifestyle therapy and agents that improve insulin sensitivity. In youth, NAFLD appears tightly correlated with components of the MetS, especially visceral fat, which appears to predict fibrosis as well as liver fat. In addition, noninvasive techniques such as transient elastography may help provide data on fibrosis in youth with NAFLD and avoid biopsy.

SUMMARY

The close association between NAFLD and the MetS supports screening for other comorbidities associated with the MetS. Further research is urgently required to best identify effective therapies to prevent and treat NAFLD, but its close association with MetS argues for a focus on strategies designed to improve insulin resistance and components of the MetS.

Nonalcoholic fatty liver disease as a comorbidity of childhood obesity

Childhood obesity is a worldwide health problem associated with an increase in the prevalence and severity of comorbid conditions including nonalcoholic fatty liver disease (NAFLD). The increasing number of children with NAFLD presents a major public health concern. This review focuses on the recent advancements in the understanding of the epidemiology, diagnosis, histology, pathogenesis and treatment of pediatric NAFLD and highlights ongoing challenges and unmet needs in the area.

Retinol-binding protein 4: a promising circulating marker of liver damage in pediatric nonalcoholic fatty liver disease

BACKGROUND & AIMS

Noninvasive methods are needed to identify pediatric nonalcoholic fatty liver disease (NAFLD), the most frequent chronic liver disease in children and adolescents in industrialized countries. Retinol-binding protein 4 (RBP4) is an adipocytokine that has been associated with the pathogenesis of insulin resistance. We tested the serum levels of RBP4 to assess their associations with the metabolic profile and histologic features in a large well-characterized group of children with NAFLD.

METHODS

The study included 59 children with biopsy-proven NAFLD. Histologic analyses were performed by an experienced hepatopathologist; the NAFLD activity score and fibrosis score were calculated for each patient. RBP4 levels in serum samples were measured by an enzyme-linked immunosorbent assay analysis. Anthropometric, blood pressure, and metabolic profile analyses (including glucose tolerance, fasting glucose, insulin, and lipid panel tests) were performed on samples from all patients.

RESULTS

Decreasing levels of RBP4 were associated significantly with increasing levels of serum triglyceride. High levels of RBP4 were associated significantly with low necroinflammatory activity, a low NAFLD activity score, and a low fibrosis score. Furthermore, serum RBP4 levels decreased significantly as disease severity increased; there was a stepwise decrease in RBP4 from children with steatosis (3.8 mg/dL) to borderline nonalcoholic steatohepatitis (2.9 mg/dL) to definitive nonalcoholic steatohepatitis (1.9 mg/dL) (P < .0001). This association remained significant after adjusting for other relevant clinical variables.

CONCLUSIONS

Our study shows an inverse relationship between RBP4 levels and degree of liver damage. RBP4 therefore might be a potential novel noninvasive marker of severity of pediatric NAFLD.

Nonalcoholic fatty liver disease in type 2 diabetes mellitus

PURPOSE OF REVIEW

To increase awareness about the close interrelationship between nonalcoholic fatty liver disease and type 2 diabetes mellitus, and of recent diagnostic and treatment advances in the field.

RECENT FINDINGS

The perception of nonalcoholic fatty liver disease as an uncommon and benign condition is rapidly changing. Approximately 70% of persons with type 2 diabetes mellitus have a fatty liver and the disease follows a more aggressive course with necroinflammation and fibrosis (i.e. nonalcoholic steatohepatitis) in diabetes. New evidence suggests that it is not steatosis per se but the development of lipotoxicity-induced mitochondrial dysfunction and activation of inflammatory pathways that leads to progressive liver damage. Nonalcoholic steatohepatitis is a leading cause of end-stage liver disease and contributes to cardiovascular disease in patients with type 2 diabetes mellitus. Because nonalcoholic steatohepatitis may develop even in the presence of normal liver transaminases, a liver biopsy is still necessary for a definitive diagnosis. However, new imaging methods and plasma biomarkers are emerging as alternative diagnostic tools. Lifestyle intervention is the gold standard for the management of nonalcoholic steatohepatitis. Recent randomized controlled trials suggest thiazolidiendiones are promising therapeutic agents.

SUMMARY

Nonalcoholic steatohepatitis is a frequently overlooked and potentially severe complication of type 2 diabetes mellitus. Patients may benefit from its early diagnosis and treatment.

Non-invasive diagnosis of steatosis and fibrosis

The prognosis and management of liver disease greatly depends on the amount of liver fibrosis. Non-alcoholic fatty liver disease (NAFLD), ranging from simple steatosis to non-alcoholic steatohepatitis (NASH), is emerging as a major cause of liver disease in Western countries because of the increasing prevalence of obesity and type 2 diabetes. A key issue in patients with NAFLD is the differentiation of NASH from simple steatosis. It is particularly important to identify NASH patients as they are at greatest risk of developing complications such as cirrhosis, liver failure and hepatocellular carcinoma. The limitations of liver biopsy (invasive procedure, sampling errors, interobserver variability and non-dynamic fibrosis evaluation) have stimulated the search for non-invasive approaches for the assessment of steatosis and liver fibrosis in patients with NAFLD. A variety of methods, including serum markers, imaging techniques such as ultrasound, CT, MRI and measurement of liver stiffness by transient elastography, have been proposed for the non-invasive assessment of steatosis and hepatic fibrosis. This review discusses the advantages and limitations of these different methods in clinical practice.

Performance of ELF serum markers in predicting fibrosis stage in pediatric non-alcoholic fatty liver disease

BACKGROUND & AIMS

Nonalcoholic fatty liver disease (NAFLD) is the most frequent chronic liver disease in children and adolescents in industrialized countries. It is important to accurately determine the stage of fibrosis in these patients. The enhanced liver fibrosis (ELF) test has been validated for staging liver fibrosis in adult patients with chronic liver diseases, including NAFLD. We investigated the performance of this test in assessing liver fibrosis in children and adolescents with NAFLD, identified by biopsy.

METHODS

The ELF test was performed on a panel of serum samples collected from 112 consecutive subjects that were likely to have NAFLD (64 male, mean age of 13.8+/-3.3). A previously described and validated algorithm was used to analyze the data on hyaluronic acid (HA), amino-terminal propeptide of type III collagen (PIIINP), and tissue inhibitor of metalloproteinase 1 (TIMP-1) levels.

RESULTS

In pediatric patients with NAFLD, the ELF test predicted liver fibrosis stage with a high degree of sensitivity and specificity; results were superior to those reported for adults. The area under receiver operating characteristic curves/best possible ELF test cut-off values for the prediction of "any" (>or= stage 1), moderate-perisinusoidal (>or= stage 1b), moderate-portal/periportal (>or= stage 1c), significant (>or= stage 2), or advanced (>or= stage 3) fibrosis were 0.92/9.28, 0.92/9.33, 0.90/9.54, 0.98/10.18 and 0.99/10.51, respectively.

CONCLUSIONS

The ELF test can be used to accurately assess the level of liver fibrosis in pediatric patients with NAFLD. This information is important for identifying patients with progressive fibrosis that require further histopathological analysis or therapeutic follow-up.