Analytical variability of the Fibrotest proteins

Fibromax-based nonalcoholic fatty liver disease in chronic obstructive pulmonary disease patients with obstructive sleep apnea: Methodological considerations

The relationship between nonalcoholic fatty liver disease (NAFLD) and obstructive sleep apnea (OSA) has been well demonstrated, but remains to be evidenced in chronic obstructive pulmonary disease (COPD). Recently, Viglino et al. (Eur Respir J, 2017) attempted to determine the prevalence of liver fibrosis, steatosis and nonalcoholic steatohepatitis (NASH) in COPD patients, some of whom had OSA, basing the NAFLD diagnostic on three circulating biomarker-based liver scores: the FibroTest, SteatoTest and NashTest, from the Fibromax® panel. Among the main findings, the absence of OSA treatment emerged as independently associated with liver fibrosis and steatosis, when compared to effective treatment. However, besides the low number of treated patients, no polysomnographic respiratory data was provided, making it difficult to differentiate the impact of OSA from that of COPD in NAFLD prevalence. Furthermore, NAFLD diagnosis relied exclusively on circulating biomarker-based liver scores, without histological, imagery or other liver exploratory methods. Therefore, in this article, some methodological points are reminded and discussed, including the choice of OSA measurements, and the significance of ActiTest and AshTest scores from Fibromax® in this pathophysiological context.

Monitoring fibrogenic progression in the liver

The clinical course of chronic liver diseases is significantly dependent on the progression rate of fibrosis which is the unstructured replacement of injured parenchyma by extracellular matrix. Despite intensive studies, the clinical opportunities for patients with fibrosing liver diseases have not improved. This will be changed by increasing knowledge of new pathogenetic mechanisms, which complement the "canonical principle" of fibrogenesis. The latter is based on the activation of hepatic stellate cells and their transdifferentiation to myofibroblasts induced by hepatocellular injury and consecutive inflammatory mediators such as TGF-β. Stellate cells express a broad spectrum of matrix components. New mechanisms indicate that the heterogeneous pool of (myo-)fibroblasts can be supplemented by epithelial-mesenchymal transition (EMT) from cholangiocytes and potentially also from hepatocytes to fibroblasts, by influx of bone marrow-derived fibrocytes in the damaged liver tissue and by differentiation of a subgroup of monocytes to fibroblasts after homing in the damaged tissue. These processes are regulated by the cytokines TGF-β and BMP-7, chemokines, colony-stimulating factors, metalloproteinases and numerous trapping proteins. They offer innovative diagnostic and therapeutic options. As an example, modulation of TGF-β/BMP-7 ratio changes the rate of EMT, and so the simultaneous determination of these parameters and of the connective tissue growth factor (CTGF) in serum might provide information on fibrogenic activity. Also, proteomic and glycomic approaches of serum are under investigation to set up specific protein profiles in patients with liver fibrosis. The aim of this article is to present the current pathogenetic concepts of liver fibrosis and to discuss established and novel diagnostic approaches to reflect the process of hepatic fibrogenesis in the medical laboratory.

Inflammation biomarkers in chronic hepatitis C: association with liver histopathology, HCV genotype and cryoglobulinemia

OBJECTIVE

This work investigated the profile of inflammation biomarkers in patients with chronic hepatitis C and its association with liver fibrosis, hepatic necroinflammatory activity, viral genotypes and cryoglobulinemia.

SUBJECTS AND METHODS

Seventy-eight untreated patients were studied. Biomarker levels were determined by immunoassays, cryoglobulinemia by cryoprecipitation and liver histopathology investigated using METAVIR scores.

RESULTS

Decreased levels of α(1)-acid glycoprotein (AGP), C3 and haptoglobin (Hp) were observed in the patients (P < 0.0001). Increased α(1)-antitrypsin (P < 0.01) and ferritin (P < 0.0001) levels were found in this group, but C-reactive protein (CRP) and C4 levels were unaltered. Alanine aminotransferase inversely correlated with Hp (P < 0.01) and AGP (P = 0.01), whereas it was directly correlated with ferritin (P < 0.05) and AGP (P < 0.0001). The levels of CRP, C3 and C4 were lower in the patients with hepatic necroinflammatory activity (P < 0.05). Patients with advanced fibrosis had low levels of Hp and AGP (P < 0.05 and P < 0.01, respectively). Neither infection with different viral genotypes nor cryoglobulinemia caused an alteration in biomarker levels.

CONCLUSION

Chronic hepatitis C virus infection alters the levels of some biomarkers, which are mainly observed in patients with liver fibrosis and hepatic necroinflammatory activity.

Assessment of new hyaluronic acid assays and their impact on FibroMeter scores

BACKGROUND

We compared three hyaluronic acid (HA) assays and analyzed the impact of their variations on FibroMeter scores.

METHODS

In a test group of 165 patients, HA levels were assessed with the commonly used ELISA assay from Corgenix, a new ELISA assay from Teco and an immunoturbidimetry assay from Wako, this latter tested across three different instruments. Five different FibroMeter scores were calculated.

RESULTS

Correlation across the three assays (r(s) between 0.969 and 0.995) was very good. Means of differences (d) were lower when the immunoturbidimetry assay was compared on different instruments: d between -3.4 and 2.0 μg/L. However, a higher value for HA measurement was observed with Corgenix assay, compared to the other two assays (Teco and Wako): d between 27.1 and 36.4 μg/L. The assessment also demonstrated that HA variations had very little impact on FibroMeter scores: 0.0117 for virus and 0.0416 for alcoholic fibrosis scores, and between 0.58 and 1.71 for the area of fibrosis (expressed in percentage).

CONCLUSIONS

The two new assays found lower values of HA, as compared to the Corgenix assay. However, these differences had very little impact on FibroMeter scores and had no impact on clinical evaluation of liver fibrosis.

Non-invasive biomarkers for monitoring the fibrogenic process in liver: A short survey

The clinical course of chronic liver diseases is significantly dependent on the progression rate and the extent of fibrosis, i.e. the non-structured replacement of necrotic parenchyma by extracellular matrix. Fibrogenesis, i.e. the development of fibrosis can be regarded as an unlimited wound healing process, which is based on matrix (connective tissue) synthesis in activated hepatic stellate cells, fibroblasts (fibrocytes), hepatocytes and biliary epithelial cells, which are converted to matrix-producing (myo-)fibroblasts by a process defined as epithelial-mesenchymal transition. Blood (non-invasive) biomarkers of fibrogenesis and fibrosis can be divided into class I and class II analytes. Class I biomarkers are those single tests, which are based on the pathophysiology of fibrosis, whereas class II biomarkers are mostly multiparametric algorithms, which have been statistically evaluated with regard to the detection and activity of ongoing fibrosis. Currently available markers fulfil the criteria of ideal clinical-chemical tests only partially, but increased understanding of the complex pathogenesis of fibrosis offers additional ways for pathophysiologically well based serum (plasma) biomarkers. They include TGF-β-driven marker proteins, bone marrow-derived cells (fibrocytes), and cytokines, which govern pro- and anti-fibrotic activities. Proteomic and glycomic approaches of serum are under investigation to set up specific protein or carbohydrate profiles in patients with liver fibrosis. These and other novel parameters will supplement or eventually replace liver biopsy/histology, high resolution imaging analysis, and elastography for the detection and monitoring of patients at risk of developing liver fibrosis.

GlycoFibroTest is a highly performant liver fibrosis biomarker derived from DNA sequencer-based serum protein glycomics

Liver fibrosis is currently assessed by liver biopsy, a costly and rather cumbersome procedure that is unsuitable for frequent patient monitoring, which drives research into biomarkers for this purpose. To investigate whether the serum N-glycome contains information suitable for this goal, we developed a 96-well plate-based serum N-glycomics sample preparation protocol that only involves fluid transfer steps and incubations in a PCR thermocycler yielding 8-aminopyrene-1,3,6-trisulfonic acid-labeled N-glycans. These N-glycans are then ready for analysis on the capillary electrophoresis-based DNA sequencers that are the current standard in clinical genetics laboratories worldwide. Subsequently we performed a multicenter, blinded study of 376 consecutive chronic hepatitis C virus patients for which liver biopsies and extensive serum biochemistry data were available. Among patients, the METAVIR fibrosis stage distribution was as follows: 10.6% F0, 44.4% F1, 20.5% F2, 18.4% F3, and 6.1% F4. We found that the ratio of two N-glycans, here called GlycoFibroTest, correlates with the histological fibrosis stage equally well as FibroTest (rho = 0.4-0.5 in F1-F4), which is used in the clinic today. Finally using affinity chromatography we depleted sera of immunoglobulin G, and this resulted in a complete removal of the undergalactosylated biantennary glycans from the N-glycome, which are partially determining GlycoFibroTest.

GlycoFibroTest is a highly performant liver fibrosis biomarker derived from DNA sequencer-based serum protein glycomics

Liver fibrosis is currently assessed by liver biopsy, a costly and rather cumbersome procedure that is unsuitable for frequent patient monitoring, which drives research into biomarkers for this purpose. To investigate whether the serum N-glycome contains information suitable for this goal, we developed a 96-well plate-based serum N-glycomics sample preparation protocol that only involves fluid transfer steps and incubations in a PCR thermocycler yielding 8-aminopyrene-1,3,6-trisulfonic acid-labeled N-glycans. These N-glycans are then ready for analysis on the capillary electrophoresis-based DNA sequencers that are the current standard in clinical genetics laboratories worldwide. Subsequently we performed a multicenter, blinded study of 376 consecutive chronic hepatitis C virus patients for which liver biopsies and extensive serum biochemistry data were available. Among patients, the METAVIR fibrosis stage distribution was as follows: 10.6% F0, 44.4% F1, 20.5% F2, 18.4% F3, and 6.1% F4. We found that the ratio of two N-glycans, here called GlycoFibroTest, correlates with the histological fibrosis stage equally well as FibroTest (rho = 0.4-0.5 in F1-F4), which is used in the clinic today. Finally using affinity chromatography we depleted sera of immunoglobulin G, and this resulted in a complete removal of the undergalactosylated biantennary glycans from the N-glycome, which are partially determining GlycoFibroTest.

Biomarkers of liver fibrosis

Liver biopsy, due to its limitations and risks, is an imperfect gold standard for assessing the severity of the most frequent chronic liver diseases. This chapter summarized the advantages and the limits of the available biomarkers of liver fibrosis. Among a total of 2237 references, a total of 14 validated biomarkers have been identified between 1991 and 2007. Nine were not patented and five were patented. FibroTest (FT) was the most studied test with 33 different populations including 6549 patients and 925 controls. The mean diagnostic value for the diagnosis of advanced fibrosis assessed using standardized area under the receiver operating characteristics (ROC) curves was 0.84 [95% confidence interval (CI), 0.83-0.86], without significant difference between the causes of liver disease, hepatitis C, hepatitis B, alcoholic or nonalcoholic fatty liver disease. High-risk profiles of false negative/positive of FT are present in 3% of populations, mainly Gilbert syndrome, hemolysis, and acute inflammation. FT has higher accuracy than aspartate aminotransferase/platelets ratio index (APRI), the most used nonpatented test. No significant difference has been observed between the five patented tests. A quality score has been assessed in order to compare the quality of fibrosis biomarkers. Neither biomarkers nor biopsy are sufficient alone to take definitive decision in a given patient and all the clinical and biological data must be taken into account. Due to the evidence-based data, health authorities in some countries have already approved validated biomarkers as first-line procedure for the staging of liver fibrosis. This overview of evidence-based data suggests that biomarkers could be used as an alternative to liver biopsy for the assessment of fibrosis stage in the four more common chronic liver diseases: C virus (HCV), hepatitis B virus (HBV), hepatitis nonalcoholic fatty liver disease (NAFLD), and alcoholic liver disease (ALD). Neither biomarkers nor biopsy are sufficient alone to take definitive decision in a given patient and all the clinical and biological data must be taken into account.

Optimized stepwise combination algorithms of non-invasive liver fibrosis scores including Hepascore in hepatitis C virus patients

BACKGROUND

Non-invasive liver fibrosis scores such as Hepascore (HS) have been proposed as an alternative to liver biopsy in hepatitis C virus (HCV)-infected patients.

AIM

To validate HS as an alternative to liver biopsy and Fibrotest (FT) and propose five optimized combination algorithms to improve diagnostic accuracy.

METHODS

The cohort included 467 patients with HCV. There were 274/467 (59%) men, and mean age was 47 +/- 12 years.

RESULTS

Hepascore area under ROC curves (AUC) for > or =F2, F3F4 and F4 diagnosis were 0.82, 0.84 and 0.90 respectively, in the same range as FT. HS and FT were concordant in 387/467 (82%) for fibrosis staging. Among these patients, 342/387 (88%) were concordant with liver biopsy. AUCs of aspartate aminotransferase (AST) to Platelets Ratio Index (APRI) and Forns for > or =F2 were 0.76 and 0.73 (0.65-0.79) respectively. The algorithm combining APRI and HS had the highest rate of avoided liver biopsies (45%) with a high diagnostic accuracy (91%).

CONCLUSIONS

Hepascore is an accurate non-invasive marker for > or =F2 and F4 diagnosis in HCV patients. In a pragmatic approach, a stepwise optimized algorithm combining APRI and FT or HS considerably increases diagnostic accuracy and avoided liver biopsies.

Biomarkers of hepatic fibrosis, fibrogenesis and genetic pre-disposition pending between fiction and reality

Fibrosis is a frequent, life-threatening complication of most chronic liver diseases. Despite major achievements in the understanding of its pathogenesis, the translation of this knowledge into clinical practice is still limited. In particular, non-invasive and reliable (serum-) biomarkers indicating the activity of fibrogenesis are scarce. Class I biomarkers are defined as serum components having a direct relation to the mechanism of fibrogenesis, either as secreted matrix-related components of activated hepatic stellate cells and fibroblasts or as mediators of extracellular matrix (ECM) synthesis or turnover. They reflect primarily the activity of the fibrogenic process. Many of them, however, proved to be disappointing with regard to sensitivity and speci-ficity. Up to now hyaluronan turned out to be the relative best type I serum marker. Class II biomarkers comprise in general rather simple standard laboratory tests, which are grouped into panels. They fulfil most criteria for detection and staging of fibrosis and to a lesser extent grading of fibrogenic activity. More than 20 scores are currently available, among which Fibrotest™ is the most popular one. However, the diagnostic use of many of these scores is still limited and standardization of the assays is only partially realized. Combining of panel markers in sequential algorithms might increase their diagnostic validity. The translation of genetic pre-disposition biomarkers into clinical practice has not yet started, but some polymorphisms indicate a link to progression and outcome of fibrogenesis. Parallel to serum markers non-invasive physical techniques, for example, transient elastography, are developed, which can be combined with serum tests and profiling of serum proteins and glycans.

FibroMAX: towards a new universal biomarker of liver disease?

Among the noninvasive alternatives to liver biopsy, several studies have demonstrated the predictive value and a better benefit-to-risk ratio than biopsy of five combinations of simple serum biochemical markers (the super combination being FibroMAX (BioPredictive, Paris, France) in patients at risk of chronic liver diseases: FibroTest (BioPredictive) for the quantitative assessment of fibrosis; SteatoTest (BioPredictive) for the quantitative assessment of steatosis; ActiTest (BioPredictive) for the quantitative assessment of necroinflammatory activity in chronic viral hepatitis C and B; NashTest (BioPredictive) for the categorical diagnosis of nonalcoholic steatohepatitis; and AshTest for the quantitative assessment of alcoholic steatohepatitis (also known in the USA as HCV-FibroSURE, HBV-FibroSURE, ASH-FibroSURE and NASH-FibroSURE; LabCorp, NC, USA). The possible causes of false-negative and false-positive results are also better identified. These tests, which are now available in 50 countries, can facilitate the screening and management of the most frequent liver diseases.

Reproducibility of blood tests of liver fibrosis in clinical practice

OBJECTIVES

To evaluate the inter-laboratory reproducibility of blood test for liver fibrosis: FibroMeter, Fibrotest, APRI and their composites variables.

DESIGN AND METHODS

Four studies, including 147 patients, were performed: study #1 included 2 metachronous blood samples and 2 laboratories; studies #2, #3 and #4 included synchronous samples with assays delayed at day 1 in 12 laboratories, at day 0 in 10 laboratories and at day 0 or 1 in 2 laboratories, respectively. Agreement was evaluated by the intraclass correlation coefficient (r(ic)).

RESULTS

In studies #1, #2 and #4, r(ic) for FibroMeter was 0.893, 0.942 and 0.991, respectively. In study #3, the r(ic) were: FibroMeter: 0.963, Fibrotest: 0.984, APRI: 0.949. Large simulated variations in composite variables had a weak impact on FibroMeter.

CONCLUSIONS

When blood marker limits are controlled, inter-laboratory agreement of blood tests is excellent in clinical practice conditions. Blood tests are robust against the variability of composite blood variables.

Intérêt et limites des méthodes non invasives de prédiction de la fibrose hépatique au cours de l'hépatite C: une alternative à la biopsie hépatique

Biochemical markers of liver fibrosis, because they can be tested noninvasively, reproducibly, and reliably, may constitute a true alternative to liver biopsies. Scores must be used only in the circumstances for which they have been validated. Scores for the Fibrotest-Actitest have been studied and validated most widely. Fibroscan, an imaging technique that uses transient elastrography to measures liver stiffness, has been validated acceptably for management of hepatitis C (HCV). General practitioners can order Fibroscan testing to assess the extent of hepatic lesions in patients with chronic HCV. Fibrotest and/or Fibroscan testing may replace liver biopsy in patients who can then receive first-or second-line treatment for HCV, regardless of genotype or transaminase levels. In the future, treatment decisions will probably rely on a combination (after validation) of these scores and on the development of genetic markers for fibrogenesis, to differentiate between patients highly likely and unlikely to develop serious fibrosis.

Biomarkers of liver fibrosis: clinical translation of molecular pathogenesis or based on liver-dependent malfunction tests

BACKGROUND

Fibrosis is the excessive deposition and histological redistribution of extracellular matrix (ECM) in the tissue as consequence of chronic liver damage. It leads to progressive liver insufficiency, portal hypertension and ultimately to cirrhosis and primary liver cell carcinoma. There is a strong demand for reliable, organ- and disease-specific, non-invasive biomarkers of fibrosis and fibrogenesis to replace or to complement the invasive method of needle biopsy, which is afflicted with a high degree of sampling error.

METHODS

A systematic literature search was performed using electronic databases and reference lists of relevant publications to ascertain studies with non-invasive biomarkers of liver fibrosis.

RESULTS

Two classes of serum biomarkers can be differentiated: Class I markers are those, which reflect ECM turnover (fibrogenesis and fibrolysis) and/or fibrogenic cell changes, mainly of hepatic stellate cells, which are the dominant profibrogenic cell type in liver. They are mostly cost intensive, single laboratory tests and derive from the translation of fibrogenic mechanisms into clinical application. Examples are procollagen peptides, hyaluronan, and laminin. Class II biomarkers are based on algorithmic evaluation of commonly observed functional alterations of the liver that do not necessarily reflect ECM metabolism and/or fibrogenic cell changes. About 20 numerical scores or indices are reported for parameters, which are mostly routine laboratory tests and frequently multiparametric (panels). Among them fibrotest, hepascore, ELF-score have reached limited clinical application.

CONCLUSIONS

Up to now the impact of both classes of biomarkers for diagnosis and monitoring of fibrosis, fibrogenesis, and fibrolysis is limited. They cannot replace needle biopsy but some of them might be complementary in follow-up studies. Innovative methods like proteomics and glycomics to establish fibrosis-specific serum protein and glycosylation patterns, respectively, might have a high potential for diagnosis and monitoring of fibrogenesis.

Non-invasive assessment of chronic liver and gastric diseases

BACKGROUND

In patients with both chronic liver diseases and dyspepsia there is the need for non-invasive, inexpensive and effective laboratory tests. These tests should not substitute but complement and integrate the information derived from invasive techniques such as liver biopsy and esofagogastroduodenoscopy. Natural history studies indicate that advanced fibrosis and cirrhosis develop in about 20%-40% of patients with chronic hepatitis B or C, and in a similar proportion of those with alcoholic or non-alcoholic steatohepatitis. In these patients, precise definition of the hepatic fibrosis stage is the most important parameter to assess the risk of disease progression and to decide for an immediate and appropriate antiviral therapy.

METHODS

Liver biopsy represents the gold standard for evaluating the presence, type and stage of liver fibrosis but a body of evidence has been accumulated to demonstrate the limitations of this technique, including inter- and intra-observer variations, sampling errors and variability. In recent years there has been an increasing interest in the possibility of identifying and describing liver fibrosis by using non-invasive, surrogate markers measurable in blood. Many studies have been dedicated to the evaluation of "direct" markers of fibrogenesis, while a second approach is based on the evaluation of single or combined biochemical parameters that reflect the stage of liver disease. Upper gastrointestinal symptoms are common in developed countries and this makes impossible the use of esofagogastroduodenoscopy in all patients with dyspepsia. The Maastricht 2-2000 Consensus meeting has suggested screening and treating Helicobacter pylori infection in dyspeptic patients in primary health care as the first line of therapy for newly onset dyspepsia.

CONCLUSIONS

Combination panels of biomarkers have been demonstrated to improve the accuracy of the single tests and with the use of algorithms based on sequential combination of non-invasive biomarkers a high diagnostic accuracy has been achieved for liver fibrosis. This, in turn, translates in a reduction by >50% in the need of taking liver biopsies. A biochemical panel which includes the measurement of serum pepsinogen I and II, gastrin G-17 and anti-H. pylori antibodies for patients with gastric disease, due to its high negative predictive value, appears to be a valuable approach to screen patients <55 years and with no alarm features, assuring safety and cost-effectiveness.

Sampling variability of computer-aided fractal-corrected measures of liver fibrosis in needle biopsy specimens

AIM: To assess the sampling variability of computer-aided, fractal-corrected measures of fibrosis in liver biopsies.

METHODS: Samples were derived from six to eight different parts of livers removed from 12 patients with clinically and histologically proven cirrhosis undergoing orthotopic liver transplantation. Sirius red-stained sections with a thickness of 2 μm were digitized using a computer-aided image analysis system that automatically measures the surface of fibrosis, as well as its outline perimeter, fractal surface and outline dimensions, wrinkledness, and Hurst coefficient.

RESULTS: We found a high degree of inter-sample variability in the measurements of the surface [coefficient of variation (CV) = 43% ± 13%] and wrinkledness (CV = 28% ± 9%) of fibrosis, but the inter-sample variability of Hurst’s exponent was low (CV = 14% ± 2%).

CONCLUSION: This study suggests that Hurst’s exponent might be used in clinical practice as the best histological estimate of fibrosis in the whole organ, and evidences the fact that biopsy sections, which are fundamental for the qualitative diagnosis of chronic hepatitis, play a key role in the quantitative estimate of architectural changes in liver tissue.

[Noninvasive assessment of liver fibrosis in patients with chronic hepatitis virus C]

Development of liver fibrosis, which leads to cirrhosis, is the principal complication of all chronic liver diseases, regardless of their cause. Knowledge of the existence and severity of fibrosis is important from diagnostic and prognostic viewpoints. Its assessment plays an essential role in the treatment decision and makes it possible to assess the risk of progression to cirrhosis and the onset of its complications. Histologic examination of the liver remains the reference examination for assessing the extent of fibrosis during chronic liver disease. Nonetheless, the number of patients needing assessment, the risks of the punch-biopsy and the cost of this invasive examination have led many to propose other tools to assess fibrosis. Some standard indicators (transaminases, platelets, prothrombin time) have long been recognized as indirect markers of extensive fibrosis. More recently, progress in our knowledge of the mechanisms of liver fibrogenesis have made it possible to identify different peripheral blood components that may be of clinical interest. Thus serum assays of elements of the extracellular matrix, their decay products, or enzymes involved in their metabolism have been proposed as noninvasive indicators. Among these, hyaluronic acid appears the most interesting. For several years, scores have been calculated with algorithms that combine several indicators determined simultaneously to assess fibrosis in patients with hepatitis C and sometimes other chronic liver diseases. The Fibrotest is the best validated and most widely used of these. Finally, Fibroscan is a device for the diagnosis and quantification of hepatic fibrosis, based on the technique of transient elastography. The relative roles of these noninvasive markers and the value of their combinations must still be determined.

A prospective analysis of the prognostic value of biomarkers (FibroTest) in patients with chronic hepatitis C

BACKGROUND

FibroTest, a noninvasive method of measuring biomarkers of liver fibrosis, is an alternative to liver biopsy for determining the severity of chronic hepatitis C virus (HCV) infection. We compared the 5-year prognostic value of the FibroTest with biopsy staging for predicting cirrhosis decompensation and survival in patients with chronic HCV infection.

METHODS

Fibrosis stage was assessed on the same day by FibroTest and biopsy in a prospective cohort of 537 patients. Disease classification at baseline was 157 patients with severe fibrosis (FibroTest >0.58), 137 with moderate fibrosis (FibroTest 0.32-0.58), and 243 with no or minimal fibrosis (FibroTest <0.32).

RESULTS

In 64 untreated patients with severe fibrosis, survival without HCV complications was 73% [95% confidence interval (CI), 59%-086%; 13 complications], and survival without HCV-related death was 85% (95% CI, 73%-96%; 7 HCV deaths). Survival rates were higher in patients with moderate fibrosis, [99% (95% CI, 97%-100%; 1 complication; P <0.001) and 100% (no HCV death; P <0.001) for patients with and without HCV-related complications, respectively], and in patients with minimal fibrosis [100% (no complication; P <0.001 vs severe) and 100% (no HCV death; P <0.001 vs severe), respectively]. FibroTest was a better predictor than biopsy staging for HCV complications, with area under the ROC curves (AUROC) = 0.96 (95% CI, 0.93%-0.97%) vs 0.91 (95% CI, 0.85%-0.94%; P = 0.01), respectively; it was also a better predictor for HCV deaths: AUROC = 0.96 (95% CI, 0.93%-0.98%) vs 0.87 (95% CI, 0.70%-0.94%; P = 0.046), respectively. The prognostic value of FibroTest was still significant (P <0.001) in multivariate analyses after taking into account histology, treatment, alcohol consumption, and HIV coinfection.

CONCLUSION

The FibroTest measurement of HCV biomarkers has a 5-year prognostic value similar to that of liver biopsy.

Do we still need a liver biopsy? Are the serum fibrosis tests ready for prime time?

Liver biopsy has been in use for more than a century for diagnosis and staging of acute and chronic liver diseases. Several serum markers and panels offer the opportunity to assess the extent of liver disease noninvasively and spare some patients the risks associated with percutaneous liver biopsy, but only a few of the noninvasive serum markers allow the determination of different stages of fibrosis on a continuum similar to that achieved with liver biopsy. This article reviews the results of recent published and preliminary studies on serum markers, focusing on their comparison with liver biopsy and their clinical utility.

Noninvasive markers of fibrosis for longitudinal assessment of fibrosis in chronic liver disease: are they ready for prime time?

Over the past decade, there has been a renewed enthusiasm to develop noninvasive serum markers or tests to assess the presence and severity of fibrosis in chronic liver disease. Although a single marker or test has lacked the necessary accuracy to predict fibrosis, different combinations of these markers or tests have shown encouraging results. However, inter-laboratory variability and inconsistent results with liver diseases of varying etiologies have made it difficult to assess the reliability of these markers in clinical practice. In this issue of the journal, Poynard et al. describe the "histological" response to lamivudine in patients with chronic Hepatitis B Virus (HBV) over a 24-month period using surrogate serum biomarkers (Fibrotest-Actitest, FT-AT) without corroborating histological data. Investigators found improvement in fibrosis and inflammation in 85% and 91%, respectively, despite the emergence of YMDD mutation in 41.5% of patients. The higher improvement rates reported in this study should be interpreted with caution for a number of reasons including the absence of data on virological response rates, corroboratory histological data, and data on the validity of FT to evaluate fibrosis in a longitudinal manner. Although FT has been studied extensively by the authors of the current study, to date there are only few independent studies. In addition to significant inter-laboratory variations, these studies have shown that significant fibrosis could be missed, or conversely significant fibrosis diagnosed in the absence of minimal or no fibrosis in about 15% to 20% of patients. We may be approaching a time when serum biomarkers may become an integral part of the assessment of patients with chronic liver disease, but published evidence suggests that these markers are not yet ready for prime time.

Non invasive fibrosis biomarkers reduce but not substitute the need for liver biopsy

Chronic liver diseases are very common worldwide, particularly those linked to viral hepatitis and to alcoholic and non-alcoholic fatty liver. Their natural history is variable and long-term evolution differs in individual patients. Optimised clinical management of compensated chronic liver diseases requires precise definition of the stage of liver fibrosis, the main determinant of prognosis and of most therapeutic decisions. Liver biopsy is the gold standard for assessment of hepatic fibrosis. However, it is invasive with possible complications, costly and prone to sampling errors. Many non-invasive markers of liver fibrosis have been recently proposed and assessed in the clinical setting as surrogates of liver biopsy. Direct markers are based on biochemical parameters directly linked to fibrogenesis while indirect markers use simple or more sophisticated parameters that correlate with liver fibrosis stages. Non-invasive markers of liver fibrosis have been tested in different forms of chronic liver disease and showed variable diagnostic performance, but accuracy rarely was above 75%-80%. Better results were obtained when markers were combined. On this line, we have recently proposed a set of algorithms that combine sequentially indirect non-invasive markers of liver fibrosis, reaching 90%-95% diagnostic accuracy with significant reduction in the need for liver biopsy. Based on available evidence, it can be anticipated that non-invasive markers of liver fibrosis and their combined use will soon become a most useful tool in the clinical management of many forms of chronic liver disease. However, their implementation is expected to reduce, but not to completely eliminate, the need for liver biopsy.

[Serum markers of non-invasive fibrosis in chronic hepatitis C virus infection]

MATTER: Liver biopsy is recommended for the management of patients infected by hepatitis C virus (HCV) and is currently the gold standard in assessing liver histology. It's an invasive test prone to complications with a morbidity rate of 0.3 to 0.6% and a mortality rate up to 0.05%. Since the last decade, researchers developed non invasifs biomarkers of liver fibrosis as an alternative to liver biopsy. These scores are based on different algorithms with various combinations of biomarkers issued from extra-cellular matrix, serum and cells.

CURRENT EVENTS

The diagnostic performance of these scores, estimated by the AUROC for significant fibrosis (>F2), in patients with chronic hepatitis C reach 0.78 to 0.90 for the most accurate. In HIV-HCV co-infected patients and patients with hepatitis C cirrhosis the diagnostic performance of these scores reach 0.74 to 0.88 and 0.73 to 0.97 respectively.

PERSPECTIVES

Liver fibrosis biomarkers constitutes an alternative to liver biopsy due to their non invasive approach, their easy reproducibility and accuracy. However, these scores must be used only after a validation in multicentric independent studies. The future is based on the comparison and validation of these scores after laboratory methods standardization.

Liver fibrosis and tissue architectural change measurement using fractal-rectified metrics and Hurst’s exponent

AIM: To provide the accurate alternative metrical means of monitoring the effects of new antiviral drugs on the reversal of newly formed collagen.

METHODS: Digitized histological biopsy sections taken from 209 patients with chronic C virus hepatitis with different grade of fibrosis or cirrhosis, were measured by means of a new, rapid, user-friendly, fully computer-aided method based on the international system meter rectified using fractal principles.

RESULTS: The following were described: geometric perimeter, area and wrinkledness of fibrosis; the collation of the Knodell, Sheuer, Ishak and METAVIR scores with fractal-rectified metric measurements; the meaning of the physical composition of fibrosis in relation to the magnitude of collagen islets; the intra- and inter-biopsy sample variability of these parameters; the “staging” of biopsy sections indicating the pathway covered by fibrosis formation towards its maximum known value; the quantitative liver tissue architectural changes with the Hurst exponent.

CONCLUSION: Our model provides the first metrical evaluations of the geometric properties of fibrosis and the quantitative architectural changes of the liver tissue. The representativeness of histological sections of the whole liver is also discussed in the light of the results obtained with the Hurst coefficient.

Noninvasive markers of fibrosis for longitudinal assessment of fibrosis in chronic liver disease: are they ready for prime time?

Over the past decade, there has been a renewed enthusiasm to develop noninvasive serum markers or tests to assess the presence and severity of fibrosis in chronic liver disease. Although a single marker or test has lacked the necessary accuracy to predict fibrosis, different combinations of these markers or tests have shown encouraging results. However, interlaboratory variability and inconsistent results with liver diseases of varying etiologies have made it difficult to assess the reliability of these markers in clinical practice. In this issue of the Journal, Poynard and colleagues describe the "histological" response to lamivudine in patients with chronic HBV over a 24-month period using surrogate serum biomarkers (FibroTest-ActiTest) without corroborating histological data. Investigators found improvement in fibrosis and inflammation in 85% and 91%, respectively, despite the emergence of YMDD mutation in 41.5% of patients. The higher improvement rates reported in this study should be interpreted with caution for a number of reasons including the absence of data on virological response rates, corroboratory histological data, and data on the validity of FibroTest to evaluate fibrosis in a longitudinal manner. Although FibroTest has been studied extensively by the authors of the current study, to date there are only few independent studies. In addition to significant interlaboratory variations, these studies have shown that significant fibrosis could be missed, or conversely significant fibrosis diagnosed in the absence of minimal or no fibrosis in about 15-20% of patients. We may be approaching a time when serum biomarkers may become an integral part of the assessment of patients with chronic liver disease, but published evidence suggests that these markers are not yet ready for prime time.