Serum markers of hepatic fibrogenesis in chronic hepatitis type C treated with alfa-2A interferon

Clinical importance of laboratory biomarkers in liver fibrosis

Hepatic cirrhosis is a major health problem across the world, causing high morbidity and mortality. This disease has many etiologies, yet the result of chronic hepatic injury is hepatic fibrosis causing cirrhosis and hepatocellular carcinoma, as the liver’s architecture is progressively destroyed. While liver biopsy is currently the gold standard for fibrosis staging, it has significant disadvantages, leading to a growing interest in non-invasive markers. Direct biomarkers – hyaluronic acid, laminin, collagen type III N-peptide, type IV collagen and cholylglycine – are new and rarely applied in routine clinical practice. This is the case primarily because there is no general consensus regarding the clinical application and effectiveness of the individual biomarkers. The usage of these markers in routine clinical practice could be advantageous for patients with liver fibrosis, requiring a simple blood test instead of a biopsy. The former option would be especially attractive for patients who are contraindicated for the latter. This review summarizes recent findings on direct biomarkers of liver fibrosis and highlights their possible applications and potential benefit for liver fibrosis diagnostics and/or staging.

Principles of diagnosis and treatment of alcohol-induced liver fibrosis

Alcohol-related liver diseases are one of the leading causes of death worldwide, primarily due to complications of liver cirrhosis (LC). Early detection of alcohol-induced liver fibrosis (LF) is a difficult task, since often  alcoholic liver disease (ALD) is clinically manifested only at late stages. Given that not all alcoholic suffer from ALD, the widespread use of liver biopsy to verify the diagnosis is not advisable. Despite the variety of proposed non-invasive methods for assessing the severity of LF in patients with ALD, none of them has sufficient validation and therefore cannot be recommended for widespread use in clinical practice. The most well-studied transient elastography, due to its suboptimal specificity, can be effectively used only to exclude clinically significant LF or LC. The only proven approach to treat ALD is persistent and total alcohol abstinence. While the therapeutic options for patients with severe forms of acute hepatitis remain unchanged since the 70s of the last century and are based mainly on the use of corticosteroids, currently, there are no approaches to antifibrotic therapy of ALD approved by the guidelines. At the same time, modern achievements in understanding the pathophysiological mechanisms  of this disease  have served  as an impetus  for  the development  of ways to solve  the problem. In particular, providing intestinal eubiosis may be an important goal for the prevention and treatment of alcohol-induced LF. Randomized controlled multicenter trials involving a large number of patients are needed to confirm this and other hypotheses related to antifibrotic therapy of ALD and to accept them as a standard of medical care.

Potential role of noninvasive biomarkers during liver fibrosis

Various types of liver disease exist, such as hepatitis and alcoholic liver disease. These liver diseases can result in scarring of liver tissue, cirrhosis, and finally liver failure. During liver fibrosis, there is an excess and disorganized accumulation of extracellular matrix (ECM) components which cause the loss of normal liver cell functions. For patients with chronic liver disease, fibrosis prediction is an essential part of the assessment and management. To diagnose liver fibrosis, several invasive and noninvasive markers have been proposed. However, the adoption of invasive markers remains limited due to their inherent characteristics and poor patient acceptance rate. In contrast, noninvasive markers can expedite the clinical decision through informed judgment about disease stage and prognosis. These noninvasive markers are classified into two types: Imaging techniques and serum biomarkers. However, the diagnostic values of biomarkers associated with liver fibrosis have also been analyzed. For example, the serum levels of ECM proteins can react to either matrix accumulation or degradation. During virus-host interactions, several regulatory steps take place to control gene expression, such as the change in cellular microRNA expression profiles. MicroRNAs are a class of non-coding RNAs (18-20 long nucleotides) that function by post-transcriptional regulation of gene expression. Although various noninvasive markers have been suggested in recent years, certain limitations have restricted their clinical applications. Understanding the potential of non-invasive biomarkers as a therapeutic option to treat liver fibrosis is still in progress.

Noninvasive Biomarkers of Liver Fibrosis: An Overview

Chronic liver diseases of differing etiologies are among the leading causes of mortality and morbidity worldwide. Establishing accurate staging of liver disease is very important for enabling both therapeutic decisions and prognostic evaluations. A liver biopsy is considered the gold standard for assessing the stage of hepatic fibrosis, but it has many limitations. During the last decade, several noninvasive markers for assessing the stage of hepatic fibrosis have been developed. Some have been well validated and are comparable to liver biopsy. This paper will focus on the various noninvasive biochemical markers used to stage liver fibrosis.

From fatty liver to fibrosis: A tale of “second hit”

Although much is known about how fat accumulates in the liver, much remains unknown about how this causes sustained hepatocellular injury. The consequences of injury are recognized as nonalcoholic steatohepatitis (NASH) and progressive fibrosis. The accumulation of fat within the hepatocytes sensitizes the liver to injury from a variety of causes and the regenerative capacity of a fatty liver is impaired. An additional stressor is sometimes referred to as a “second hit” in a paradigm that identifies the accumulation of fat as the “first hit”. Possible candidates for the second hit include increased oxidative stress, lipid peroxidation and release of toxic products such as malondialdehyde and 4-hydroxynonenal, decreased antioxidants, adipocytokines, transforming growth factor (TGF)-β, Fas ligand, mitochondrial dysfunction, fatty acid oxidation by CYPs (CYP 2E1, 4A10 and 4A14), and peroxisomes, excess iron, small intestinal bacterial overgrowth, and the generation of gut-derived toxins such as lipopolysaccharide and ethanol. Oxidative stress is one of the most popular proposed mechanisms of hepatocellular injury. Previous studies have specifically observed increased plasma and tissue levels of oxidative stress markers and lipid peroxidation products, with reduced hepatic and plasma levels of antioxidants. There is also some indirect evidence of the benefit of antioxidants such as vitamin E, S-adenosylmethionine, betaine, phlebotomy to remove iron, and N-acetylcysteine in NASH. However, a causal relationship or a pathogenic link between NASH and oxidative stress has not been established so far. A number of sources of increased reactive oxygen species production have been established in NASH that include proinflammatory cytokines such as tumor necrosis factor (TNF)-α, iron overload, overburdened and dysfunctional mitochondria, CYPs, and peroxisomes. Briefly, the pathogenesis of NASH is multifactorial and excess intracellular fatty acids, oxidant stress, ATP depletion, and mitochondrial dysfunction are important causes of hepatocellular injury in the steatotic liver.

Markers in nonalcoholic steatohepatitis

Nonalcoholic fatty liver disease (NAFLD), the most common liver disorder worldwide, encompasses a spectrum of abnormal liver histology ranging from simple steatosis to nonalcoholic steatohepatitis (NASH) and cirrhosis. Population studies show that NAFLD is strongly associated with insulin resistance, obesity, type 2 diabetes mellitus, and lipid abnormalities. In the context of hepatic steatosis, factors that promote cell injury, inflammation, and fibrosis include oxidative stress, early mitochondrial dysfunction, endoplasmic reticulum stress, iron accumulation, apoptosis, adipocytokines, and stellate cell activation. The exact NASH prevalence is unknown because of the absence of simple noninvasive diagnostic tests. Although liver biopsy is the "gold standard" for the diagnosis of NASH, other tests are needed to facilitate the diagnosis and greatly reduce the requirement for invasive liver biopsy. In addition, the development of new fibrosis markers in NASH is needed to facilitate the assessment of its progression and the effectiveness of new therapies. The aim of this chapter, which is overview of biomarkers in NASH, is to establish a systematic approach to laboratory findings of the disease.

Genomics and proteomics in liver fibrosis and cirrhosis

Genomics and proteomics have become increasingly important in biomedical science in the past decade, as they provide an opportunity for hypothesis-free experiments that can yield major insights not previously foreseen when scientific and clinical questions are based only on hypothesis-driven approaches. Use of these tools, therefore, opens new avenues for uncovering physiological and pathological pathways. Liver fibrosis is a complex disease provoked by a range of chronic injuries to the liver, among which are viral hepatitis, (non-) alcoholic steatohepatitis and autoimmune disorders. Some chronic liver patients will never develop fibrosis or cirrhosis, whereas others rapidly progress towards cirrhosis in a few years. This variety can be caused by disease-related factors (for example, viral genotype) or host-factors (genetic/epigenetic). It is vital to establish accurate tools to identify those patients at highest risk for disease severity or progression in order to determine who are in need of immediate therapies. Moreover, there is an urgent imperative to identify non-invasive markers that can accurately distinguish mild and intermediate stages of fibrosis. Ideally, biomarkers can be used to predict disease progression and treatment response, but these studies will take many years due to the requirement for lengthy follow-up periods to assess outcomes. Current genomic and proteomic research provides many candidate biomarkers, but independent validation of these biomarkers is lacking, and reproducibility is still a key concern. Thus, great opportunities and challenges lie ahead in the field of genomics and proteomics, which, if successful, could transform the diagnosis and treatment of chronic fibrosing liver diseases.

Circulating markers of liver fibrosis progression

INTRODUCTION

Fibrogenesis is a typical reaction of the liver to injury. In the case of overstimulation of fibrogenesis clinically significant fibrosis and, eventually, cirrhosis occur. Treatment of liver cirrhosis is limited, therefore it is important to screen and monitor patients at risk of cirrhosis. Noninvasive parameters are ideal for this purpose due to their risk profile and repeatability.

METHODS

Systematic review of literature.

RESULTS

Among large number of proposed biomarkers, there is a distinct difference between two groups or classes. Class I biomarkers are associated with the process of fibrogenesis, their presence in the serum is the result of the increased turnover of extracellular matrix. Class II biomarkers and their combinations are mostly markers of liver function or structural damage. We have identified 27 Class I and 13 Class II biomarkers that have been proposed in the literature. We have evaluated in detail those which reached limited clinical application.

CONCLUSION

General clinical acceptance of these biomarkers is low because of various drawbacks. Simple and readily available biomarkers have low accuracy in predicting liver fibrosis and more advanced markers have low cost-benefit ratio. Therefore liver biopsy remains the "gold standard" for diagnosis of fibrosis. However potential noninvasive alternatives exist and their implementation could be valuable.

Long-term histological prognosis and serum fibrosis markers in chronic hepatitis C patients treated with interferon

BACKGROUND

Interferon (IFN) therapy is effective in 20-40% of patients with chronic hepatitis C, but the relationship between histological changes and the response to interferon is still unclear. We investigated the long-term histological prognosis and the changes of serum fibrosis markers after interferon therapy relation to the response.

METHODS AND RESULTS

One hundred and eighteen patients with chronic hepatitis C who received interferon therapy were divided into four groups based on the detection of viremia and the serum alanine aminotransferase (ALT) level after treatment. A histological examination was performed by using the histological activity index and the criteria of the METAVIR score. Serum fibrosis markers were used to measure the levels of hyaluronic acid and type IV collagen 7s. Responders, whose serum ALT levels became normal after treatment, demonstrated histological improvement. Histological improvement was more rapid in sustained virological responders with hepatitis C virus (HCV) RNA seronegativity than in biochemical responders with HCV-RNA seropositivity. Only sustained virological responders exhibited histological cure. In partial responders, whose serum ALT levels decreased to less than twice the upper of normal, and non-responders whose serum ALT levels were not reduced, liver fibrosis was unchanged or showed progression. Serum fibrosis markers increased with progression of the histological stage and varied depending on the response to interferon.

CONCLUSION

Normalization of serum ALT levels after interferon therapy led to a histological improvement, and that with viral clearance achieved histological cure. Serum fibrosis markers were useful indicators for long-term according to the response of IFN therapy.

Serum pro-collagen III peptide levels are related to lobular necrosis in untreated patients with chronic hepatitis C

OBJECTIVE

Liver biopsy is mandatory for correctly grading and staging chronic hepatitis activity. Nevertheless, serum markers of fibrogenesis may be useful to help us understand the mechanisms of the fibrogenic process, to follow-up patients, and to establish the efficacy of therapy. In this study, our aim was to identify the relationships between pro-collagen III peptide (PIIIP) serum levels and detailed liver histology in a group of untreated patients with chronic hepatitis C (CHC).

METHODS

We studied 147 CHC patients. Correlation analysis of PIIIP serum levels was performed in 109 patients, after having excluded those with alcohol abuse or concomitant hepatitis B virus infection. PIIIP serum levels were assessed using an assay that measures both Col 1-3 peptide (reflecting collagen synthesis) and Col 1 peptide (reflecting collagen degradation). Relationships of serum PIIIP with histology was carried out by evaluating grading and staging separately. Moreover, each component of the necro-inflammatory score was also taken into consideration.

RESULTS

PIIIP levels were abnormal in 101 patients (93%). Moreover, PIIIP levels were no different between patients with (12.1 +/- 6.3 ng/ml) or without (13 +/- 5.8 ng/ml) fibrosis. In univariate analysis, no relationship was observed with fibrosis (rs = 0.033, not significant), while PIIIP levels were significantly correlated with lobular necrosis only (rs = 0.295, P = 0.0020). Multivariate analysis confirmed this latter finding (P = 0.0150). Among biochemical parameters, PIIIP showed relationships with aminotransferase (AST, rS = 0.294, P = 0.0022; ALT, rs = 0.236, P = 0.0142) and alkaline phosphatase (rs = 0.146, P = 0.0223).

CONCLUSIONS

In patients with CHC, serum PIIIP levels reflect histological parameters strictly related to fibrogenesis. Therefore, PIIIP is a useful tool to evaluate ongoing fibrogenic activity of CHC. A complete histological score is needed in order to understand the relationships between biochemical markers of fibrogenesis and histology.

Hepatic fibrosis: are any of the serum markers useful?

There is a clinical need for noninvasive measurement of liver fibrosis both to diagnose significant liver fibrosis and to monitor the effects of therapy on fibrogenesis and fibrolysis. Multiple clinical markers have been evaluated over the years, and as our understanding of the molecular process of liver scarring has advanced, newer markers have appeared. Serum markers include extracellular matrix proteins such as the N-terminal propeptide of collagen III, hyaluronan, YKL-40, laminin, metalloproteinases, and their inhibitors. Use of multiple markers has led to 90% sensitivity in diagnosing cirrhosis, but specificity is variable at about 60%. Automated systems to measure these markers are under development and are being evaluated for their ability to monitor fibrosis during and after therapy in multiple liver diseases, including hepatitis B and C. Although no individual fibrosis marker is clinically applicable today, we foresee a future in which monitoring fibrosis markers will replace sequential liver biopsy as a standard of care.

Chronic hepatitis C and interferon alpha: conventional and cumulative meta-analyses of randomized controlled trials

OBJECTIVE

The purpose of this study was to evaluate the clinical usefulness of surrogate markers of the interferon effect (i.e., alanine aminotransferase levels and serum HCV-RNA status) as predictors of long term response, and to identify the optimal schedule of treatment for patients with chronic hepatitis C by means of meta-analysis.

METHODS

Pertinent randomized clinical trials and prospective studies were selected using MEDLINE (1986-1996), a reference list from published articles or reviews. Twenty-six prospective studies reporting data on surrogate markers of interferon response were selected. Thirty-nine trials comparing interferon alpha to no treatment and 25 trials comparing different schedules of interferon were reviewed. Conventional meta-analysis according to the DerSimonian and Laird method was used for the pooling of results.

RESULTS

The pooled probability of late relapse among sustained responders with negative serum HCV-RNA 6 months after treatment was very low (8.7%; 95% confidence interval 5.8-11.6%). The overall risk difference between treated and control groups was 16.63% (95% confidence interval 11.95-21.31%) for sustained aminotransferase normalization. Therapy with higher interferon dose compared with standard dose significantly improves the rate of sustained response (pooled risk difference 10.56%, 95% CI 5.47-15.65%). Cumulative meta-analyses suggest that a clear dose-response relationship exists across a wide range of interferon dosages. The multivariate meta-regression model confirms that the total interferon dose is an independent predictor of sustained response and that it seems more important than the length of treatment.

CONCLUSIONS

Testing for serum HCV-RNA, 6 months after interferon therapy in sustained biochemical responders, is useful for predicting long term response. The current standard total interferon dose of 234 mega-units is suboptimal. Further trials that directly compare different schedules of treatment are needed.

Collagen-related markers of bone turnover reflect the severity of liver fibrosis in patients with primary biliary cirrhosis

The influence of a nonskeletal disease with increased connective tissue synthesis or degradation in the collagen-related markers of bone turnover has been evaluated in 34 women with primary biliary cirrhosis (PBC; age range 41-81 years), a disease with increased hepatic fibrosis, often associated with osteoporosis. Serum osteocalcin (BGP), and carboxy-terminal (PICP) and amino-terminal (PINP) propeptides of type I collagen were assessed as indexes of bone formation, whereas serum tartrate-resistant acid phosphatase (TRAP), and cross-linked carboxy-terminal telopeptide of type I collagen (ICTP), and urinary hydroxyproline (HYP), pyridinoline (PYR), deoxypyridinoline (DPYR), and type I collagen cross-linked N- (NTX) and C-telopeptide (CTX) were measured as markers of bone resorption. The histologic stage of the disease and serum amino-terminal propeptide of type III collagen (PIIINP) as an index of liver fibrogenesis were also evaluated. BGP levels were significantly lower, whereas PICP and PINP levels were higher in patients than in controls. Among the bone resorption markers, serum ICTP and urinary PYR, DPYR, HYP, NTX, and CTX levels were significantly higher in patients than in controls. Serum PIIINP levels were also increased in PBC patients. BGP did not correlate with PICP and PINP, but these markers of bone formation as well as ICTP, PYR, DPYR, and NTX correlated with serum PIIINP levels. Serum TRAP did not correlate with collagen-related markers of bone resorption. Moreover, patients with PIIINP and bilirubin above normal levels had higher PICP, PINP, ICTP PYR, DPYR, CTX, and NTX. These markers correlated with the histologic stage of the disease, but not with osteopenia measured by densitometric procedures in 22 patients. In conclusion, collagen-related markers of bone turnover do not reflect bone remodeling in PBC. The close association of these markers with PIIINP and the clinical and histologic stage of the liver disease suggests that they are influenced by liver collagen metabolism.

N-terminal peptide of type III procollagen: a possible predictor of colorectal carcinoma recurrence

BACKGROUND

The first step of colorectal carcinoma spread depends on the ability of the tumor cells to degrade and invade the extracellular matrix (ECM). The objectives of the current study were to evaluate the serum pattern of laminin, C-terminal peptide of Type I (PIP), and N-terminal peptide of Type III (PIIIP) procollagens, markers of ECM synthesis, in the follow-up of patients after resection for colorectal carcinoma and to evaluate their role in predicting local recurrence or metastases.

METHODS

A total of 32 patients who had undergone resection for colorectal carcinoma were followed for a median period of 24 months (range, 6-36 months). Every 3 months, laminin, PIP, and PIIIP were measured in the sera together with the tumor markers carcinoembryonic antigen (CEA), CA 19-9, and tissue plasminogen activator (TPA). Twenty-one patients (Group 1) had no signs of recurrence, whereas the remaining 11 (Group 2) developed hepatic (n = 7) or pulmonary (n = 4) metastases.

RESULTS

No variations were observed in either group for laminin, CEA, CA 19-9, or TPA, whereas significant increases in PIP and PIIIP were observed in both groups 3 months after surgery. The increase in PIP and PIIIP at the 3-month follow-up was significantly greater in Group 1 than in Group 2. The difference between values at 3 months and basal values enabled a discrimination between Group 1 and Group 2, with a sensitivity of 36% and 91% and a specificity of 71% and 71% for PIP and PIIIP, respectively.

CONCLUSIONS

The authors believe PIIIP is useful as an early prognostic indicator of recurrence in the follow-up of patients who have undergone radical resection for colorectal carcinoma.

Serum hyaluronan as a disease marker

Hyaluronan is a connective tissue polysaccharide which has also been found in blood serum in concentrations < 100 micrograms/L (average 30-40 micrograms/L in middle-aged persons). The serum level is regulated by the influx of the polysaccharide from the tissues via lymph and its receptor-mediated clearance by liver endothelial cells. Markedly high serum levels are noted in certain liver diseases, especially in patients with cirrhosis, when the clearance is impaired. In these cases serum hyaluronan can be used to follow the development of the disease. Serum hyaluronan is also a sensitive marker for impending rejection of liver transplants. Patients with rheumatoid arthritis constitute another major group with increased serum hyaluronan, but in this case the level varies markedly during the day corresponding to physical activity. There are good indications that in these subjects the excess hyaluronan comes from the joints. Under stringent sampling conditions of serum it should be possible to extract interesting information on the inflammatory joint process. Increased hyaluronan levels are also seen in other inflammatory diseases and it is of special interest that high hyaluronan levels in patients with septic conditions is a sign of poor prognosis. Certain tumours, notably Wilms' tumour and mesothelioma, produce factors which activate synthesis of hyaluronan and increase its serum level. Rare hereditary diseases with disturbances of hyaluronan metabolism and elevated blood levels have also been discovered, e.g. Werner's syndrome and cutaneous hyaluronanosis. Information accumulated during the last decade regarding the metabolism of hyaluronan has made this polysaccharide an interesting clinical marker for a number of pathological conditions.