Serum fibrosis markers: death by validation or a leap of faith?

Golgi protein 73 in liver fibrosis

Golgi protein 73 (GP73) is implicated in key pathogenic processes, particularly those related to inflammation and fibrogenesis. In the last years, its measurement has emerged as a promising biomarker for detection of liver fibrosis (LF), a common consequence of chronic liver disease that can progress to cirrhosis and eventually hepatocellular carcinoma. GP73 concentrations in blood appear significantly increased in LF patients, correlating with disease severity, making this biomarker a possible non-invasive alternative for detecting and monitoring this condition regardless of etiology. Understanding the molecular mechanisms involving GP73 expression could also lead to new therapeutic strategies aimed at modulating its synthesis or function to prevent or reverse LF. Despite its clinical potential, GP73 as a LF biomarker faces several challenges. The lack of demonstrated comparability among different assays as well as the lack of knowledge of individual variability can make difficult the result interpretation. Further research is therefore needed focusing on robust clinical validation of GP73 as a LF biomarker. Addressing analytical, biological, and clinical limitations will be critical to exploiting its potential for improving detection and monitoring of advanced LF.

Development of a novel glycated protein-based fibrosis prediction score for determination of significant liver fibrosis in HCV-infected patients, a preliminary study

The current study aimed to investigate the diagnostic value of glycated albumin (GA), glycated hemoglobin (HbA1c), and a number of routine biomarkers as noninvasive indicators of liver fibrosis in patients with chronic hepatitis C (CHC). One hundred patients with CHC were subjected to full medical history and examination, in addition to ultrasound-guided liver biopsy and histopathological examination for assessment of liver fibrosis stage. GA and HbA1c values, GA/HbA1c ratio, liver function tests, complete blood count, and alpha fetoprotein (AFP) were determined. A novel noninvasive index, dubbed Fibrosis Prediction Score (FPS), was selected for predicting significant liver fibrosis based on total bilirubin, glycated albumin, platelet count, age, and AFP. A validation study for FPS was applied on archival data which include 66 diabetics' patients. The FPS had area under the curve (AUC) of 0.92 for classification of patients with significant fibrosis with 81% sensitivity and 95% specificity. The AUCs of FPS in predicting advanced fibrosis and cirrhosis were 0.86 and 0.82, respectively. Comparison of AST-to-platelet ratio index (APRI) and FIB-4 with FPS indicated increased sensitivity and specificity of FPS over APRI and FIB4 in both significant and advanced fibrosis. FPS has a good sensitivity and specificity for prediction of significant and advanced liver fibrosis in patients with CHC.

The Performance of Serum Biomarkers for Predicting Fibrosis in Patients with Chronic Viral Hepatitis

Background/Aims

The invasiveness of a liver biopsy and its inconsistent results have prompted efforts to develop noninvasive tools to evaluate the severity of chronic hepatitis. This study was intended to assess the performance of serum biomarkers for predicting liver fibrosis in patients with chronic viral hepatitis.

Methods

A total of 302 patients with chronic hepatitis B or C, who had undergone liver biopsy, were retrospectively enrolled. We investigated the diagnostic accuracy of several clinical factors for predicting advanced fibrosis (F≥3).

Results

The study population included 227 patients with chronic hepatitis B, 73 patients with chronic hepatitis C, and 2 patients with co-infection (hepatitis B and C). Histological cirrhosis was identified in 16.2% of the study population. The grade of porto-periportal activity was more correlated with the stage of chronic hepatitis compared with that of lobular activity (r=0.640 vs. r=0.171). Fibrosis stage was correlated with platelet count (r=-0.520), aspartate aminotransferase to platelet ratio index (APRI) (r=0.390), prothrombin time (r=0.376), and albumin (r=-0.357). For the diagnosis of advanced fibrosis, platelet count and APRI were the most predictive variables (AUROC=0.752, and 0.713, respectively).

Conclusions

In a hepatitis B endemic region, platelet count and APRI could be considered as reliable non-invasive markers for predicting fibrosis of chronic viral hepatitis. However, it is necessary to validate the diagnostic accuracy of these markers in another population.

Biomarkers of liver fibrosis

Liver fibrosis is the final common pathway for almost all causes of chronic liver injury. Liver fibrosis is now known to be a dynamic process having significant potential for resolution. Therefore, fibrosis prediction is an essential part of the assessment and management of patients with chronic liver disease. As such, there is strong demand for reliable liver biomarkers that provide insight into disease etiology, diagnosis, therapy, and prognosis in lieu of more invasive approaches such as liver biopsy. Current diagnostic strategies range from use of serum biomarkers to more advanced imaging techniques including transient elastography and magnetic resonance imaging. In addition to these modalities, there are other approaches including the use of novel, but yet to be validated, biomarkers. In this chapter, we discuss the biomarkers of liver fibrosis including the use of invasive and noninvasive biomarkers and disease-specific biomarkers in various chronic liver diseases.

Biomarkers for the diagnosis of acute cellular rejection in liver transplant recipients: A review

The gold standard for the diagnosis of acute cellular rejection (ACR) is a liver biopsy. The quest for an alternative non-invasive biomarkers has been long and is ongoing. However, an efficient and useful biomarker has not been developed yet. In this manuscript, we review all possible candidate biomarkers that have been studied in recent years, starting with cytokines and ending with an overview of different newly discovered "omics". Promising paths are being explored but a valid non-invasive biomarker has not been discovered yet.

Serum bile acid levels as a predictor for the severity of liver fibrosis in patients with chronic hepatitis C

Serum bile acids (SBAs) are commonly elevated in cholestatic liver diseases, but it is unclear if SBA levels are also elevated in noncholestatic chronic liver diseases and whether those levels correlate with disease severity. We analysed SBA levels of 135 consecutive patients with chronic hepatitis C virus infection and correlated these levels with the degree of liver fibrosis as determined by liver biopsy. In addition, we assessed the accuracy of SBA levels as a noninvasive predictor for liver fibrosis by its comparison to the patients' FibroTest scores. Two-thirds (90/135 patients, 67%) of the study patients had nonsevere liver fibrosis (Metavir F0-F2), and the others (45/135, 33%) had severe fibrosis or cirrhosis (Metavir F3-F4). The SBA levels were significantly higher in patients with severe fibrosis as compared to nonsevere fibrosis (11.46 ± 10.01 vs 6.37 ± 4.69, P < 0.0001). Furthermore, a receiver operator characteristics curve based on a model that included serum bile acids, age, body mass index, serum AST, glucose and cholesterol levels suggested that this combination reliably predicts the degree of liver fibrosis and is not inferior to the current noninvasive FibroTest score (areas under the curve of 0.837 vs 0.83, respectively, P = 0.87). We conclude that measurement of SBA levels may have a clinical role as a simple noninvasive tool to assess the severity of HCV-induced liver disease. Combined with widely available laboratory parameters, SBA levels can predict disease severity with a high degree of accuracy.

[Non-alcoholic fatty liver disease. How and who to screen]

Non-alcoholic fatty acid disease (NAFLD) can develop in the context of multiple processes but the main etiologic association is undoubtedly with insulin resistance syndrome. The present review aims to provide a systematic diagnostic approach that should include the following basic elements: a) a suspected diagnosis of NAFLD, including confirmation of abstinence from alcohol, exclusion of other potential causes of liver steatosis and diagnosis of potential associated diseases; b) diagnosis of insulin resistance; c) diagnosis of potential associated diseases; d) adequate evaluation of vascular risk; e) diagnosis of the type and localization of fat, and finally, f) evaluation of the severity of NAFLD, which can be performed through invasive and non-invasive techniques.

Serum surrogate markers of liver fibrosis in primary biliary cirrhosis

BACKGROUND

Hyaluronan, leptin, laminin and collagen IV have been used extensively for the assessment of liver fibrosis. The aim of this study was to assay these markers in the peripheral and hepatic vein blood of primary biliary cirrhosis (PBC) patients and to study their ability to discriminate early from advanced disease.

METHODS

Sera from 62 PBC patients were compared to 60 controls, 44 chronic Hepatitis C, 38 hepatocellular carcinoma and 34 viral cirrhosis patients. Serum from the hepatic vein of 15 cirrhotic PBC patients and 17 patients with viral cirrhosis was also assayed.

RESULTS

All disease groups had significantly increased levels of hyaluronan and collagen IV, compared to controls, while laminin was significantly increased only in viral cirrhosis. Hyaluronan levels were statistically different between early (54.5 ng/ml; 95%CI 27.3-426.9) and late PBC (154.5 ng/ml; 95%CI 55.3-764.4, p<0.05). The area under the curve (AUC) for the identification of late PBC was 0.74 for hyaluronan, 0.63 for leptin, 0.59 for laminin and 0.70 for collagen IV. Hyaluronan had high sensitivity and NPV in identifying late stages of PBC (96% and 90%, respectively). Short term UDCA had no effect on these markers.

CONCLUSION

No single measurement can differentiate between advanced and early fibrosis in PBC. However serum hyaluronan is a promising single serum marker for longitudinal studies in PBC.

Noninvasive assessment of liver fibrosis

Liver biopsy has long been an important tool for assessing the degree of liver fibrosis. Information on the presence and degree of liver fibrosis is useful before making therapeutic decisions or predicting disease outcomes. The need to stage liver fibrosis, however, should decrease as treatment options become more successful (as has occurred with viral hepatitis). In recent years, noninvasive tests have demonstrated a reasonable ability to identify significant fibrosis, cirrhosis in particular, nor is it surprising that liver disease specialists and patients favor a noninvasive approach. However, only those tests with the highest diagnostic accuracy, cost-effectiveness, and availability should be implemented. Apart from their diagnostic accuracy, the potential ability of these tests to predict disease outcomes (a more relevant endpoint) should be compared with that of liver biopsy. Indeed, the use of a standardized system to evaluate the utility of biomarkers would facilitate their implementation in clinical practice.