Technology Insight: noninvasive assessment of liver fibrosis by biochemical scores and elastography

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.

Chronic hepatitis B: whom to treat and for how long? Propositions, challenges, and future directions

Recent guidelines of the American Association for the Study of Liver Diseases, the European Association for the Study of the Liver, and the Asian Pacific Association for the Study of the Liver 2008 update of the "Asian-Pacific consensus statement on the management of chronic hepatitis B" offer comprehensive recommendations for the general management of chronic hepatitis B (CHB). These recommendations highlight preferred approaches to the prevention, diagnosis, and treatment of CHB. Nonetheless, the results of recent studies have led to an improved understanding of the disease and a belief that current recommendations on specific therapeutic considerations, including CHB treatment initiation and cessation criteria, particularly in patient populations with special circumstances, can be improved. Twelve experts from the Asia-Pacific region formed the Asia-Pacific Panel Recommendations for the Optimal Management of Chronic Hepatitis B (APPROACH) Working Group to review, challenge, and assess relevant new data and inform future updates of CHB treatment guidelines. The significance of and controversy about reported findings were discussed and debated in an expert meeting of the Working Group in Beijing, China, in November 2008. This review paper attempts to identify areas requiring improved CHB management and provide suggestions for future guideline updates, with special emphasis on treatment initiation and duration.

Prospective comparison of two algorithms combining non-invasive methods for staging liver fibrosis in chronic hepatitis C

BACKGROUND & AIMS

Non-invasive assessment of liver fibrosis is a challenging area. Several methods have been proposed in patients with chronic hepatitis C (CHC) but their performance may be improved when they are combined as suggested by recently proposed algorithms using either transient elastography (TE) and Fibrotest (FT) (Castera) or AST-to-Platelet Ratio Index (APRI) and FT (SAFE biopsy). The aim of this prospective study was to compare the performance of these two algorithms for diagnosing significant fibrosis and cirrhosis in 302 CHC patients.

METHODS

All patients underwent TE, FT and APRI the same day as liver biopsy, taken as reference standard.

RESULTS

Significant fibrosis (Metavir F>or=2) was present in 76% of patients and cirrhosis (F4) in 25%. TE failure was observed in eight cases (2.6%). For significant fibrosis, Castera algorithm saved 23% more liver biopsies (71.9% vs. 48.3%, respectively; p<0.0001) than SAFE biopsy but its accuracy was significantly lower (87.7% vs. 97.0%, respectively; p<0.0001). Regarding cirrhosis, accuracy of Castera algorithm was significantly higher than that of SAFE biopsy (95.7% vs. 88.7%, respectively; p<0.0001). The number of saved liver biopsies did not differ between the two algorithms (78.8% vs. 74.8%; p=NS).

CONCLUSIONS

Both algorithms are effective for non-invasive staging of liver fibrosis in chronic hepatitis C. Although the number of liver biopsies avoided does not differ between algorithms for diagnosing cirrhosis, it is significantly higher with Castera algorithm than SAFE biopsy for significant fibrosis.

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.

FibroMeters: a family of blood tests for liver fibrosis

FibroMeters are blood tests for liver fibrosis with several specificities: two main diagnostic targets (fibrosis stage and area of fibrosis); adaptation to specific causes; and results confirmed by an expert system. Thus, FibroMeters comprise six different tests: one for staging and one for quantitation of liver fibrosis in each of the three main causes of chronic liver disease-chronic viral hepatitis, alcoholic liver disease (ALD) and non-alcoholic fatty liver disease (NAFLD). FibroMeters display a high overall diagnostic accuracy and are the only tests to correctly classify 100% of HCV patients without fibrosis or with cirrhosis. They have 90% predictive values in a higher proportion of patients than with other usual blood tests. A 90% correct classification is available in 100% of HCV patients with the following reliable diagnostic intervals: F0/1, F1/2, F2+/-1, F3+/-1. In real-life conditions, the reproducibility of FibroMeters is higher than that of liver biopsy or ultrasonographic elastometry. FibroMeters are robust tests with the most stable diagnostic performance across different centers. Optional tests are also available, such as a specific one for cirrhosis, which has a diagnostic accuracy of 93.0% (AUROC: 0.92) and a 100% positive predictive value for diagnosis of HCV cirrhosis. Determination by FibroMeters of the area of fibrosis - the only direct, non-invasive, quantitative measurement of liver fibrosis - are especially useful for following-up cirrhosis as it correlates well with clinical events. FibroMeters are also very accurate in HVB or HIV-HCV co-infected patients. The tests specific for ALD and NAFLD also have a high diagnostic accuracy (AUROCs: 0.96 and 0.94, respectively, for significant fibrosis).

Non invasive diagnosis of portal hypertension in cirrhotic patients

The measure of disease progression in chronic liver disease represents a key challenge in any of the different stages of evolution. Indeed, a correct and reliable measure of the stage of the disease has relevant implications for assessing the effectiveness of the current therapeutic regimens and for predicting the occurrence of complication. Accordingly, a current major effort is directed at evaluating methodologies characterized by no or low invasiveness to be employed as clinical discriminators in patients populations potentially requiring invasive assessment. This appears particularly relevant in patients with compensated cirrhosis, where the only reference standard is the measurement of portal pressure by hepatic venous pressure gradient (HVPG). In this particular context, transient elastography (TE) appears to be promising and needs to be further investigated, possibly in combination with other non-invasive methodologies such as serum markers algorithms and/or imaging techniques. On the other hand, the application of non-invasive methods for monitoring the response to vasoactive treatment for the reduction of portal pressure and the prevention of related complications seems at the moment not realistic.

Comparison of noninvasive markers of fibrosis in patients with nonalcoholic fatty liver disease

BACKGROUND & AIMS

There is a need for a reliable and inexpensive noninvasive marker of hepatic fibrosis in patients with nonalcoholic fatty liver disease (NAFLD). We compared the performance of the FIB4 index (based on age, aspartate aminotransferase [AST] and alanine aminotransferase [ALT] levels, and platelet counts) with 6 other non-invasive markers of fibrosis in patients with NAFLD.

METHODS

Using a nation-wide database of 541 adults with NAFLD, jackknife-validated areas under receiver operating characteristic curves (AUROC) of FIB4 and 7 other markers were compared. The sensitivity at 90% specificity, 80% positive predictive value, and 90% negative predictive values were determined along with cutoffs for advanced fibrosis.

RESULTS

The median FIB4 score was 1.11 (interquartile range = 0.74-1.67). The jackknife-validated AUROC for FIB4 was 0.802 (95% confidence interval [CI], 0.758-0.847), which was higher than that of the NAFLD fibrosis score (0.768; 95% CI, 0.720-0.816; P = .09), Goteburg University Cirrhosis Index (0.743; 95% CI, 0.695-0.791; P < .01), AST:ALT ratio (0.742; 95% CI, 0.690-0.794; P < .015), AST:platelet ratio index (0.730; 95% CI, 0.681-0.779; P < .001), AST:platelet ratio (0.720; 95% CI, 0.669-0.770; P < .001), body mass index, AST:ALT, diabetes (BARD) score (0.70; P < .001), or cirrhosis discriminant score (0.666; 95% CI, 0.614-0.718; P < .001). For a fixed specificity of 90% (FIB4 = 1.93), the sensitivity in identifying advanced fibrosis was only 50% (95% CI, 46-55). A FIB4 > or = 2.67 had an 80% positive predictive value and a FIB4 index < or = 1.30 had a 90% negative predictive value.

CONCLUSIONS

The FIB4 index is superior to 7 other noninvasive markers of fibrosis in patients with NAFLD; however its performance characteristics highlight the need for even better noninvasive markers.

Predictive value of aspartate aminotransferase to alanine aminotransferase ratio for hepatic fibrosis and clinical adverse outcomes in patients with primary biliary cirrhosis

BACKGROUND

The aspartate aminotransferase to alanine aminotransferase ratio (AAR) was seldom applied for fibrosis assessment in primary biliary cirrhosis (PBC) patients.

GOALS

To validate the AAR for evaluating hepatic fibrosis, disease severity, and prognosis in patients with PBC.

STUDY

Ninety-two consecutive PBC patients were retrospectively evaluated to validate the AAR for assessing the severity of liver function, the degrees of hepatic fibrosis, and predicting outcomes.

RESULTS

AAR showed modest correlations to Mayo score, model for end-stage liver disease score, and Child-Pugh score (r2=0.156,P<0.001; r2=0.084, P=0.005; r2=0.142, P<0.001, respectively)in evaluating the severity of liver function. For 46 patients who underwent liver biopsy, 35 were in early stage fibrosis and the other 11 were in advanced fibrosis. AAR was significantly higher in patients with advanced fibrosis than those with early fibrosis (mean+/-standard deviation; 1.40+/-0.44 vs. 0.98+/-0.65,P=0.001). The AAR yielded the highest area under the receiver operating curve of 0.847 than Mayo score, model for end-stage liver disease score, and Child-Pugh score in predicting advanced fibrosis. During a median follow-up of 44.5 months, 24 patients expired and 68 patients were alive. Patients with an AAR of 1 or less had significantly better prognosis than their counterparts(P=0.043).

CONCLUSIONS

AAR is a simple and reliable marker to assess liver function and hepatic fibrosis as well as to predict outcomes in PBC patients.

Targeting liver fibrosis: strategies for development and validation of antifibrotic therapies

We have made striking progress in our understanding of the biochemistry and cell biology that underlies liver fibrosis and cirrhosis, including the development of strategies and agents to prevent and reverse fibrosis. However, translation of this knowledge into clinical practice has been hampered by (1) the limitation of many in vitro and in vivo models to confirm mechanisms and to test antifibrotic agents, and (2) the lack of sensitive methodologies to quantify the degree of liver fibrosis and the dynamics of fibrosis progression or reversal in patients. Furthermore, whereas cirrhosis and subsequent decompensation are accepted hard clinical endpoints, fibrosis and fibrosis progression alone are merely plausible surrogates for future clinical deterioration. In this review we focus on an optimized strategy for preclinical antifibrotic drug development and highlight the current and future techniques that permit noninvasive assessment and quantification of liver fibrosis and fibrogenesis. The availability of such noninvasive methodologies will serve as the pacemaker for the clinical development and validation of potent antifibrotic agents.

Noninvasive laboratory tests proposed for predicting cirrhosis in patients with chronic hepatitis C are also useful in patients with non-alcoholic steatohepatitis

BACKGROUND

Several noninvasive tests have been proposed to predict cirrhosis in patients with chronic hepatitis C, but not in patients with non-alcoholic steatohepatitis (NASH). We assessed whether noninvasive laboratory tests designed to predict the risk of cirrhosis in patients with chronic hepatitis C virus (HCV) infection could be used in patients with NASH.

METHODS

The subjects were 50 patients with biopsy-proved NASH and 100 age- and sex-matched patients with HCV. Aspartate aminotransferase (AST)/alanine aminotransferase (ALT) ratio (AAR), age-platelet (AP) index, AST-to-platelet ratio index (APRI), cirrhosis discriminant score (CDS), and the hepatitis C antiviral long-term treatment against cirrhosis (HALT-C) model were calculated.

RESULTS

The areas under the receiver-operating characteristic curves of the AAR, AP index, APRI, CDS, and HALT-C model for predicting cirrhosis were respectively 0.813, 0.877, 0.786, 0.949, and 0.908 in patients with NASH and 0.555, 0.652, 0.761, 0.782, and 0.782 in patients with HCV. A CDS cutoff value of less than 5 misclassified none of the 9 patients with NASH who had cirrhosis, while a value of more than 8 misclassified none of the 41 patients with NASH without cirrhosis. With the HALT-C model, a cutoff value of less than 0.6 classified non-cirrhotic NASH, while a cutoff value of 0.97 or higher classified cirrhotic NASH. The use of CDS and HALT-C model could avoid liver biopsy for predicting cirrhosis in 60 and 48% of the patients with NASH, respectively.

CONCLUSIONS

Noninvasive laboratory tests designed to predict cirrhosis in patients with HCV are also useful in patients with NASH.

Magnetic resonance imaging and spectroscopy accurately estimate the severity of steatosis provided the stage of fibrosis is considered

BACKGROUND/AIMS

Currently the diagnosis and severity of hepatic steatosis can be established accurately only by liver biopsy. Previous small studies found that steatosis measured by magnetic resonance spectroscopy (MRS) and imaging (MRI) correlated with histological assessment of liver triglyceride content. However, the accuracy of MRS/MRI for grading the severity of steatosis has not been addressed. The aims of this study were (1) to determine whether MRS and MRI can discriminate grades of steatosis in a large cohort of consecutive patients with a wide spectrum of liver disease aetiology and severity (2) to evaluate the effect of hepatic fibrosis, inflammation and iron on quantitation of intrahepatocellular lipid (IHCL) by these techniques.

METHODS

Ninety-four sequential patients who underwent percutaneous liver biopsy or liver resection had MRS and MRI (Dixon in phase/out of phase (Dixon IP/OP) and with/without fat saturation (+/-FS) images) to determine IHCL. Histology was used as the reference standard.

RESULTS

Close relationships were observed between the percentage of steatosis estimated by histology and MRS/MRI (r(s)=0.88 p<0.001 for all techniques). However, separate equations were required for the percentage of steatosis to avoid underestimation by imaging for patients with moderate or advanced fibrosis. All techniques had good diagnostic accuracy for mild steatosis (AUROC > or =0.87) as well as moderate/severe steatosis (AUROC > or =0.89). Hepatic inflammation and mild iron deposition (Perls' grade 1 and 2) did not interfere with estimation of steatosis by imaging.

CONCLUSIONS

MRS and MRI had good accuracy for grading the severity of steatosis in subjects with liver disease, provided that stage of fibrosis was considered.

Non-invasive assessment of liver fibrosis in chronic liver diseases: implementation in clinical practice and decisional algorithms

Chronic hepatitis B and C together with alcoholic and non-alcoholic fatty liver diseases represent the major causes of progressive liver disease that can eventually evolve into cirrhosis and its end-stage complications, including decompensation, bleeding and liver cancer. Formation and accumulation of fibrosis in the liver is the common pathway that leads to an evolutive liver disease. Precise definition of liver fibrosis stage is essential for management of the patient in clinical practice since the presence of bridging fibrosis represents a strong indication for antiviral therapy for chronic viral hepatitis, while cirrhosis requires a specific follow-up including screening for esophageal varices and hepatocellular carcinoma. Liver biopsy has always represented the standard of reference for assessment of hepatic fibrosis but it has some limitations being invasive, costly and prone to sampling errors. Recently, blood markers and instrumental methods have been proposed for the non-invasive assessment of liver fibrosis. However, there are still some doubts as to their implementation in clinical practice and a real consensus on how and when to use them is not still available. This is due to an unsatisfactory accuracy for some of them, and to an incomplete validation for others. Some studies suggest that performance of non-invasive methods for liver fibrosis assessment may increase when they are combined. Combination algorithms of non-invasive methods for assessing liver fibrosis may represent a rational and reliable approach to implement non-invasive assessment of liver fibrosis in clinical practice and to reduce rather than abolish liver biopsies.

Transient elastography and other noninvasive tests to assess hepatic fibrosis in patients with viral hepatitis

The limitations of liver biopsy (invasive procedure, sampling errors, inter-observer variability and nondynamic fibrosis evaluation) have stimulated the search for noninvasive approaches for the assessment of liver fibrosis in patients with viral hepatitis. A variety of methods including the measurement of liver stiffness, using transient elastography, and serum markers, ranging from routine laboratory tests to more complex algorithms or indices combining the results of panels of markers, have been proposed. Among serum indices, Fibrotest has been the most extensively studied and validated. Transient elastography appears as a promising method but has been mostly validated in chronic hepatitis C with performance equivalent to that of serum markers for the diagnosis of significant fibrosis. The combination of both approaches as first-line assessment of liver fibrosis could avoid the performance of liver biopsy in the majority of patients with chronic hepatitis C, a strategy that deserves further evaluation in patients with hepatitis B or HIV-HCV coinfection. Transient elastography also appears to be an excellent tool for early detection of cirrhosis and may have prognostic value in this setting. Guidelines are now awaited for the use of noninvasive methods in clinical practice.

Participation of Functionally Different Macrophage Populations and Monocyte Chemoattractant Protein-1 in Early Stages of Thioacetamide-induced Rat Hepatic Injury

Macrophages are crucial in hepatic fibrogenesis. In acute hepatic necrosis induced in rats by a single injection of 300 mg/kg body weight (BW) of thioacetamide (TAA), macrophage properties were investigated using single or double immunohistochemistry. Macrophages reacting with anti-CD68, anti-CD163, or major histocompatibility complex (anti-MHC) class II antibody appeared in injured centrilobular areas on days 1-5 after injection. Increased expression of CD68 and CD163 reflect phagocytosis and production of pro-inflammatory factors, respectively. There were also macrophages double-positive to CD68/CD163, CD68/MHC class II, or CD163/MHC class II; of these, macrophages double-positive to CD68/MHC class II were most frequent, indicating that macrophages with enhanced phagocytic activity came to express MHC class II. The appearance of these macrophages corresponded to increased expression of mRNAs of monocyte chemoattractant protein-1 (MCP-1), a chemokine, on day 1, and TGF-β1, a fibrogenic factor, on day 3. Some hepatic stellate cells (HSCs) in injured areas reacted with anti-MCP-1 antibody. To investigate the effects of MCP-1, we added MCP-1 to HS-P, a rat macrophage line. Addition of MCP-1 increased immunoexpression for CD68 and CD163 and up-regulated TGF-β1 mRNA expression. Collectively, macrophages in acute hepatic necrosis may express different properties such as phagocytosis, MHC class II expression, and TGF-β1 production; such expression may be influenced by MCP-1 produced by HSCs.

Measurement of liver stiffness with two imaging techniques: magnetic resonance elastography and ultrasound elastometry

PURPOSE

To cross-validate the magnetic resonance elastography (MRE) technique with a clinical device, based on an ultrasound elastometry system called Fibroscan.

MATERIALS AND METHODS

Ten healthy subjects underwent an MRE and a Fibroscan test. The MRE technique used a round pneumatic driver at 60 Hz to generate shear waves inside the liver. An elastogram representing a map of the liver stiffness was generated allowing for the measurement of the average liver stiffness inside a region of interest. The Fibroscan technique used an ultrasound probe (3.5 MHz) composed of a vibrator that sent low-frequency (50 Hz) shear waves inside the right liver lobe. The probe acts as an emitter-receptor that measures the velocity of the waves propagated inside the liver tissue.

RESULTS

The mean shear stiffness measured with the MRE and Fibroscan techniques were 1.95+/-0.06 kPa and 1.79+/-0.30 kPa, respectively. A higher standard deviation was found for the same subject with Fibroscan.

CONCLUSION

This study shows why MRE should be investigated beyond the Fibroscan. The MRE technique provided elasticity of the entire liver, meanwhile the Fibroscan provided values of elasticity locally.

Transient elastography for measurement of liver stiffness measurement can detect early significant hepatic fibrosis in Japanese patients with viral and nonviral liver diseases

BACKGROUND

Many studies have reported the efficiency of transient elastography, a noninvasive, reproducible, and reliable method for predicting liver fibrosis, in patients with chronic hepatitis C (CHC) and B (CHB), but there are few reports about nonviral chronic liver disease (CLD) such as primary biliary cirrhosis (PBC), nonalcoholic steatohepatitis (NAFLD), and autoimmune hepatitis (AIH). We therefore compared the efficiency of transient elastography between CHC and nonviral CLD.

METHODS

We assessed the accuracy of liver stiffness measurement (LSM) using Fibroscan, and compared these values with those of hyaluronic acid, type 4 collagen, platelet count, prothrombin index, and AST/platelet ratio index (APRI) as indices for the diagnosis of liver fibrosis in 114 patients with a variety of chronic liver diseases: CHC (n = 51), CHB (n = 11), NAFLD (n = 17), PBC (n = 20), and AIH (n = 15). The histology was assessed according to the METAVIR score by two pathologists.

RESULTS

The number of fibrosis stage (F0/1/2/3/4) with CHC was 9/15/12/6/10, and that with nonviral CLD was 10/21/11/4/6, respectively. The ability, assessed by area under receiver operating characteristic (AUROC) curve, to predict liver fibrosis F >or= 2 for LSM, HA, type 4 collagen, platelet count, prothrombin index, and APRI, was 0.92, 0.81, 0.87, 0.85, 0.85, and 0.92 in CHC patients, respectively; and 0.88, 0.72, 0.81, 0.67, 0.81, and 0.77 in nonviral CLD patients, respectively.

CONCLUSIONS

In patients with nonviral CLD, LSM was most helpful in predicting significant fibrosis (F >or= 2). Transient elastography is a reliable method for predicting significant liver fibrosis, not only in CHC patients but also in nonviral CLD patients.

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.

Reversal of liver fibrosis

Hepatic fibrosis is a scarring process associated with an increased and altered deposition of extracellular matrix in the liver. It is caused by a variety of stimuli and if fibrosis continues unopposed, it would progress to cirrhosis which poses a significant health problem worldwide. At the cellular and molecular level, this progressive process is characterized by cellular activation of hepatic stellate cells and aberrant activity of transforming growth factor-beta with its downstream cellular mediators. Liver biopsy has been the reference test for assessment of hepatic fibrosis, but because of its limitations, noninvasive markers of liver fibrosis were developed. Liver fibrosis or cirrhosis was considered irreversible in the past but progress of research on the molecular pathogenesis of liver fibrosis has shown that hepatic cellular recovery is possible. Currently, no acceptable therapeutic strategies exist, other than removal of the fibrogenic stimulus, to treat this potentially devastating disease.

Fibrosis and cirrhosis reversibility: clinical features and implications

In recent years, practicing hepatologists have directed their attention to the most relevant outcome of most chronic liver diseases (CLD), ie, the progressive substitution of the functioning hepatic parenchyma with fibrotic tissue. Significant advancements in the knowledge of cellular and molecular mechanisms of hepatic fibrogenesis have greatly contributed to this change, and, currently, major efforts are directed at translating these acquisitions in diagnostic and therapeutic applications. This article outlines differences between fibrosis and cirrhosis and discusses the reversibility of CLD and the regression of fibrosis and cirrhosis. The end-points of anti-fibrotic therapy are detailed.

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

Transient elastography (TE) has received increasing attention as a means to evaluate disease progression in chronic liver disease patients. In this study, we assessed the value of TE for the prediction of fibrosis stage in a cohort of pediatric patients with nonalcoholic steatohepatitis. Furthermore, TE interobserver agreement was evaluated. TE was performed in 52 consecutive biopsy-proven nonalcoholic steatohepatitis patients (32 males, 20 females, age 13.6 +/- 2.44 years). The area under the receiver operating characteristic curves for the prediction of "any" (>or=1), significant (>or=2), or advanced fibrosis (>or=3) were 0.977, 0.992, and 1, respectively. Calculation of multilevel likelihood ratios showed that TE values <5, <7, and <9 kPa, suggest the presence of "any" fibrosis, significant fibrosis, and advanced fibrosis, respectively. TE values between 5 and 7 kPa predict a fibrosis stage of 1, but with some degree of uncertainty. TE values between 7 and 9 kPa predict fibrosis stages 1 or 2, but cannot discriminate between these two stages. TE values of at least 9 kPa are associated with the presence of advanced fibrosis. The intraclass correlation coefficient for absolute agreement was 0.961.

CONCLUSION

TE is an accurate and reproducible methodology to identify pediatric subjects without fibrosis or significant fibrosis, or with advanced fibrosis. In patients in which likelihood ratios are not optimal to provide a reliable indication of the disease stage, liver biopsy should be considered when clinically indicated.

Assessing liver fibrosis

Prognosis and management of chronic liver diseases greatly depend on the amount and progression of liver fibrosis. Although liver biopsy is still considered as the gold standard to evaluate fibrosis in the liver, it is an invasive procedure, with rare but potentially life-threatening complications, and is prone to sampling errors. These limitations have stimulated the search for new noninvasive approaches. A number of methods, including serum indices and the measurement of liver stiffness using transient elastography, have been proposed for the noninvasive assessment of hepatic fibrosis, mainly in patients with chronic hepatitis C. It can be anticipated that these noninvasive methods will become an important tool in clinical practice in the near future. This review is aimed at discussing the advantages and limits of these methods and the perspectives for their rationale for use in clinical practice.

Liver cirrhosis

Cirrhosis is defined as the histological development of regenerative nodules surrounded by fibrous bands in response to chronic liver injury, which leads to portal hypertension and end-stage liver disease. Recent advances in the understanding of the natural history and pathophysiology of cirrhosis, and in treatment of its complications, have resulted in improved management, quality of life, and life expectancy of patients. Liver transplantation remains the only curative option for a selected group of patients, but pharmacological treatments that can halt progression to decompensated cirrhosis or even reverse cirrhosis are currently being developed. This Seminar focuses on the diagnosis, complications, and management of cirrhosis, and new clinical and scientific developments.