Serum hyaluronan and aminoterminal propeptide of type III procollagen in primary biliary cirrhosis: relation to clinical symptoms, liver histopathology and outcome

Noninvasive Evaluation of Fibrosis and Portal Hypertension in Primary Biliary Cholangitis

Primary biliary cholangitis (PBC) is a chronic cholestatic liver disease that, if left untreated or insufficiently treated, inexorably progresses toward cirrhosis and its potentially fatal complications. Alongside with the biochemical response to ursodeoxycholic acid therapy, advanced liver fibrosis and portal hypertension (PH) were shown to be major prognostic determinants in PBC. Therefore, one of the goals of noninvasive PBC evaluation should be to early diagnose compensated advanced disease and/or clinically significant PH. In this article, the main methods of noninvasive assessment of liver fibrosis and PH in PBC, and their clinical relevance, will be reviewed.

Diagnostic Modalities of Non-Alcoholic Fatty Liver Disease: From Biochemical Biomarkers to Multi-Omics Non-Invasive Approaches

Non-Alcoholic Fatty Liver Disease (NAFLD) is currently the most common cause of chronic liver disease worldwide, and its prevalence is increasing globally. NAFLD is a multifaceted disorder, and its spectrum includes steatosis to steatohepatitis, which may evolve to advanced fibrosis and cirrhosis. In addition, the presence of NAFLD is independently associated with a higher cardiometabolic risk and increased mortality rates. Considering that the vast majority of individuals with NAFLD are mainly asymptomatic, early diagnosis of non-alcoholic steatohepatitis (NASH) and accurate staging of fibrosis risk is crucial for better stratification, monitoring and targeted management of patients at risk. To date, liver biopsy remains the gold standard procedure for the diagnosis of NASH and staging of NAFLD. However, due to its invasive nature, research on non-invasive tests is rapidly increasing with significant advances having been achieved during the last decades in the diagnostic field. New promising non-invasive biomarkers and techniques have been developed, evaluated and assessed, including biochemical markers, imaging modalities and the most recent multi-omics approaches. Our article provides a comprehensive review of the currently available and emerging non-invasive diagnostic tools used in assessing NAFLD, also highlighting the importance of accurate and validated diagnostic tools.

Index serum hyaluronic acid independently and accurately predicts mortality in patients with liver disease

BACKGROUND

Hyaluronic acid is a recognised noninvasive marker of liver fibrosis. However, its prognostic ability has not been extensively studied.

AIMS

To investigate the ability of an index serum hyaluronic acid measurement to independently predict transplant-free survival in patients with liver disease of varying aetiology and severity.

METHODS

This was a retrospective single-centre cohort study. Serum hyaluronic acid was measured at the discretion of the attending clinicians, in patients attending the liver clinic, to assess disease severity. Patients with a hyaluronic acid measurement between 1995 and 2010 were identified. Patient characteristics at the point of hyaluronic acid measurement were recorded from medical records. Follow-up was from date of index hyaluronic acid measurement to date of death, date of transplant or censor date (July 01, 2015). Primary outcomes were all-cause and liver-related mortality. Kaplan-Meier analysis was used to compare survival in 3 patient groups with hyaluronic acid levels of <100 μg/L, 100-300 μg/L and >300 μg/L. Survival models were constructed using Cox proportional hazard and prediction accuracy was assessed by Harrell's C-statistic.

RESULTS

Five hundred and eighty nine patients fulfilled inclusion criteria. Median follow-up was 5.6 years (range 0.1-19.7). Transplant-free survival was significantly different between patients with hyaluronic acid <100 μg/L, 100-300 μg/L and >300 μg/L for liver-related as well as all-cause mortality (P < 0.001). Hyaluronic acid level was an independent predictor of survival (liver-related: HR 1.39, 95% CI 1.20-1.60, P < 0.001; all-cause: HR 1.04, 95% CI 1.02-1.06, P = 0.001). The liver-related prediction accuracy of hyaluronic acid was 0.74 (Standard error 0.03).

CONCLUSION

Index hyaluronic acid measurement can accurately and independently predict liver-related and all-cause mortality in patients with liver disease.

Utility of Noninvasive Markers of Fibrosis in Cholestatic Liver Diseases

Methods of liver fibrosis assessment have changed considerably in the last 20 years, and noninvasive markers now have been recognized as major first-line tools in the management of patients with chronic viral hepatitis infection. But what about the efficiency and utility of these surrogate indices for the more uncommon chronic cholestatic liver diseases, namely primary biliary cirrhosis and primary sclerosing cholangitis? This article provides clinicians with a global overview of what is currently known in the field. Both diagnostic and prognostic aspects of noninvasive markers of fibrosis in cholestatic liver diseases are presented and discussed.

Hyaluronic acid as a biomarker of fibrosis in chronic liver diseases of different etiologies

Chronic liver diseases represent a significant public health problem worldwide. The degree of liver fibrosis secondary to these diseases is important, because it is the main predictor of their evolution and prognosis.

Hyaluronic acid is studied as a non-invasive marker of liver fibrosis in chronic liver diseases, in an attempt to avoid the complications of liver puncture biopsy, considered the gold standard in the evaluation of fibrosis. We review the advantages and limitations of hyaluronc acid, a biomarker, used to manage patients with chronic viral hepatitis B or C infection, non-alcoholic fatty liver disease, HIV-HCV coinfection, alcoholic liver disease, primary biliary cirrhosis, biliary atresia, hereditary hemochromatosis and cystic fibrosis.

Hyaluronan as an immune regulator in human diseases

Accumulation and turnover of extracellular matrix components are the hallmarks of tissue injury. Fragmented hyaluronan stimulates the expression of inflammatory genes by a variety of immune cells at the injury site. Hyaluronan binds to a number of cell surface proteins on various cell types. Hyaluronan fragments signal through both Toll-like receptor (TLR) 4 and TLR2 as well as CD44 to stimulate inflammatory genes in inflammatory cells. Hyaluronan is also present on the cell surface of epithelial cells and provides protection against tissue damage from the environment by interacting with TLR2 and TLR4. Hyaluronan and hyaluronan-binding proteins regulate inflammation, tissue injury, and repair through regulating inflammatory cell recruitment, release of inflammatory cytokines, and cell migration. This review focuses on the role of hyaluronan as an immune regulator in human diseases.

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 markers of liver fibrosis are highly predictive of liver-related death in a cohort of HCV-infected individuals with and without HIV infection

OBJECTIVES

Noninvasive markers of liver fibrosis correlate with the stage of liver fibrosis, but have not been widely applied to predict liver-related mortality.

METHODS

We assessed the ability of two indices of liver fibrosis, aspartate aminotransferase (AST)-to-platelet ratio index (APRI) and Fib-4, and two markers of extracellular matrix metabolism, hyaluronic acid (HA) and YKL40, to predict liver mortality in a prospective cohort of hepatitis C virus (HCV)-infected individuals with and without HIV coinfection. These were compared with two established prognostic scores, the Child-Pugh-Turcotte (CPT) and model of end-stage liver disease (MELD) scores.

RESULTS

A total of 303 subjects, of whom 207 were HIV positive at study entry, were followed up for a mean period of 3.1 years. There were 33 deaths due to liver disease. The ability of each test and score to predict 3-year liver mortality was expressed as the area under the receiver operator curve. The area under the receiver operator curve 95% confidence intervals were: HA 0.92 (0.86-0.96), CPT 0.91 (0.79-0.96), APRI 0.88 (0.80-0.93), Fib-4 0.87 (0.77-0.92), MELD 0.84 (71-0.91). In multivariate analyses HA, APRI, and fib-4 were independent predictors of mortality when included in models with MELD or CPT.

CONCLUSION

Noninvasive markers of liver fibrosis are highly predictive of liver outcome in HCV-infected individuals with and without HIV coinfection. These markers seem to have a prognostic value independent of CPT and MELD.

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.

Diagnostic accuracy of serum hyaluronic acid, FIBROSpect II, and YKL-40 for discriminating fibrosis stages in chronic hepatitis C

OBJECTIVES

Noninvasive serum markers of liver fibrosis are being used as an alternative to liver biopsy. Currently available tests distinguish, with accuracy, only absent/minimal fibrosis (Ishak stages 0-1) and advanced fibrosis/cirrhosis (Ishak stages 4-6), but not intermediate fibrosis (Ishak stages 2-3). Our aim was to evaluate the diagnostic accuracy of hyaluronic acid (HA), FIBROSpect II (FS-II), and YKL-40 (chondrex, human cartilage glycoprotein-39) in various clinically important categories of fibrosis, and further correlate these serum markers with digital quantification of fibrosis (DQF) and Ishak stages.

METHODS

Serum HA, YKL-40, and FS-II were retrospectively assessed and correlated with Ishak stages and DQF scores in 75 patients with chronic hepatitis C (HCV). Spearman's rho statistics assessed relationships among all parameters, and receiver operator characteristic curves evaluated accuracy of each parameter when compared to the Ishak stages.

RESULTS

All three serum markers and DQF correlated highly with one another (P < or = 0.01) and with Ishak stages of fibrosis. Among the serum markers, HA was effective in discriminating between Ishak stages 0-1 and Ishak stages 2-3 compared with FS-II, with an area under the curve of 0.76 versus 0.66 and a false-positive rate of 0.33 versus 0.67, respectively. All three serum markers predicted advanced fibrosis and cirrhosis. YKL-40 had the highest false-positive rates in all categories of fibrosis.

CONCLUSIONS

HA can be utilized as a reliable surrogate marker in distinguishing three clinically relevant stages of fibrosis: absent/minimal, intermediate, and advanced/cirrhosis. HA should be considered as a cost-effective alternative to other serum markers for staging fibrosis and for determining the timing and selection of HCV treatment.

[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.

Assessment of biliary fibrosis by transient elastography in patients with PBC and PSC

Noninvasive measurement of liver stiffness with transient elastography has been recently validated for the evaluation of hepatic fibrosis in chronic hepatitis C. The current study assessed the diagnostic performance of liver stiffness measurement (LSM) for the determination of fibrosis stage in chronic cholestatic diseases. One hundred one patients with primary biliary cirrhosis (PBC, n=73) or primary sclerosing cholangitis (PSC, n=28) were prospectively enrolled in a multicenter study. All patients underwent liver biopsy (LB) and LSM. Histological and fibrosis stages were assessed on LB by two pathologists. LSM was performed by transient elastography. Efficiency of LSM for the determination of histological and fibrosis stages were determined by a receiver operating characteristics (ROC) curve analysis. Analysis failed in six patients (5.9%) because of unsuitable LB (n=4) or LSM (n=2). Stiffness values ranged from 2.8 to 69.1 kPa (median, 7.8 kPa). LSM was correlated to both fibrosis (Spearman's rho= 0.84, P < .0001) and histological (0.79, P < .0001) stages. These correlations were still found when PBC and PSC patients were analyzed separately. Areas under ROC curves were 0.92 for fibrosis stage (F) > or =2, 0.95 for F > or =3 and 0.96 for F=4. Optimal stiffness cutoff values of 7.3, 9.8, and 17.3 kPa showed F > or =2, F > or =3 and F=4, respectively. LSM and serum hyaluronic acid level were independent parameters associated with extensive fibrosis on LB. In conclusion, transient elastography is a simple and reliable noninvasive means for assessing biliary fibrosis. It should be a promising tool to assess antifibrotic therapies in PBC or PSC.

Evaluation of liver fibrosis: a concise review

The diagnosis of liver fibrosis has traditionally relied on liver biopsy. However, recent studies have suggested that there can be up to a 33 % error in the diagnosis of cirrhosis. In this article, we review the current status of liver biopsy as a gold standard for the diagnosis of liver fibrosis and discuss the radiological and serum tests that have been proposed as potential adjuncts or alternatives to biopsies. Indirect markers of liver fibrosis which reflect alterations in liver function and or inflammation are discussed as well as more direct markers of liver fibrosis. The limitations of utilization of these markers for both cross-sectional diagnosis of fibrosis and monitoring disease progression or regression are discussed.

Quantitative testing of liver function compared to prognostic scores in patients with primary biliary cirrhosis

AIM

Primary biliary cirrhosis (PBC) is a slowly progressive liver disease which can lead to cirrhosis. We investigated if quantitative tests of liver function (QTLF) and serum levels of a surrogate marker of hepatic fibrogenesis (PIIINP) provide information in addition to established prognostic scores.

METHODS

In 34 PBC patients PIIINP, PBC-relevant parameters, histological staging and QTLF at entry and at 2 years were determined and compared with the Christensen (CPS I, CPS II) and Mayo prognosis score. QTLF included aminopyrine breath test, galactose elimination capacity, sorbitol and indocyanine green clearance.

RESULTS

Bilirubin, serum IgM and PIIINP were elevated at both time points, whereas albumin and prothrombin time remained normal. Clinical findings (ascites, cirrhosis, central cholestasis) and histological staging worsened after 2 years, as did the CPS II. However, QTLF, PIIINP, CPS I and the Mayo score revealed no significant changes.

CONCLUSIONS

Only CPS II changed after 2 years, whereas CPS I and the Mayo score remained unaltered. QTLF and PIIINP did not provide any further information on progression of PBC, suggesting that QTLF cannot predict prognosis of PBC patients in a two-year interval and that CPS II is superior to CPS I and the Mayo score in short-term studies for PBC.

[11C]Hyaluronan uptake with positron emission tomography in liver disease

BACKGROUND

A hyaluronan-loading test has been developed for assessment of hyaluronan kinetics and applied in patients with liver and joint diseases. This test describes the metabolic process of hyaluronan but cannot define the specific contribution of different organs. A method for labelling of hyaluronan with the short-lived positron-emitting radionuclide 11C has been published and in this study applied in healthy subjects and liver diseases.

MATERIALS AND METHODS

Positron emission tomography (PET) was used for the regional assessment and quantification of [11C]hyaluronan uptake in three healthy subjects, four patients with alcoholic liver cirrhosis, one with alcoholic hepatitis and one with liver steatosis. After intravenous administration of 60 MBq of 11C-labelled hyaluronan, a 55-min PET scan was performed over the liver and plasma radioactivity was analysed. Rate constants describing the transport of the [11C]hyaluronan tracer from plasma to the liver were calculated.

RESULTS

High uptake was observed in the liver combined with a rapid elimination of tracer from plasma. The liver uptake rate (k1) was significantly lower in patients (0.018 min-1) than in healthy subjects (0.043 min-1, P = 0.002). The rate constants seem to be related to the severity of the disease as defined by the Child-Pugh score.

CONCLUSIONS

The study suggests that PET with [11C]hyaluronan could be an accurate method by which to assess liver dysfunction, in conditions where endothelial cell function is impaired. The possibility of quantification over extended portions of the body also opens up possibilities to explore regional differences in liver function and to assess other elimination routes of hyaluronan.

Aminoterminal propeptide of type III procollagen and hyaluronan in patients with primary biliary cirrhosis: markers of fibrosis in primary biliary cirrhosis

The aminoterminal propeptide of type III procollagen (PIIINP) and hyaluronan have previously been studied in different liver diseases. The results of these studies are controversial. The aim of the present study was to examine the relationship between PIIINP and hyaluronan levels and the clinical, biochemical and histological features of primary biliary cirrhosis (PBC) and its prognosis. Fifty-five PBC patients were studied at the time of diagnosis of PBC and were followed up for a mean of 58 months. During the follow-up period 21 patients died. In addition, 30 healthy subjects were examined in the present study. Hyaluronan and PIIINP were measured by radioimmunoassay and the levels of both PIIINP and hyaluronan were higher in PBC patients than in healthy volunteers (P < 1.8 x 10(-6) and 1.6 x 10(-9), respectively). Hyaluronan and PIIINP levels were above normal values in 82 and 84% of PBC patients, respectively. There were correlations between PIIINP and hyaluronan and the histological stage of PBC (r = 0.44, P < 0.004 and r = 0.56, P < 0.00001, respectively). The correlation between PIIINP and hyaluronan was 0.46 (P < 0.0035). In symptomatic patients, both PIIINP and hyaluronan values were higher than in controls (P < 0.002 and P < 0.006, respectively). The levels of PIIINP correlated significantly with bilirubin (r = 0.43, P < 0.006), while hyaluronan was correlated with age (r = 0.33, P < 0.015), pruritus (r = 0.32, P < 0.02), fatigue (r = 0.41, P < 0.003), hepatomegaly (r = -0.46, P < 0.0008), the presence of oesophageal varices (r = 0.34, P < 0.002), weight loss (r = 0.29, P < 0.05), bilirubin (r = 0.54, P < 0.0001), albumin (r = -0.30, P < 0.04), extent of fat excretion (r = 0.53, P < 0.009) and length of symptomatic period before diagnosis of PBC (r = 0.43, P < 0.002). Using Cox's logistic regression analysis, survival was found to be influenced by bilirubin concentration but not by hyaluronan, PIIINP, age, albumin or histological stage. Therefore, hyaluronan is a more sensitive marker for predicting advanced PBC than is PIIINP. However, neither hyaluronan nor PIIINP gave any indication of prognostic outcome.

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.

Clinical significance of serum hyaluronan in patients with chronic viral liver disease

In order to elucidate the clinical significance of serum hyaluronan in chronic viral hepatitis, serum hyaluronan concentrations were measured using a sandwich enzyme binding assay in 115 patients with chronic viral hepatitis. These findings were examined in relation to the results of laboratory liver tests, levels of serum markers for fibrosis and liver histological findings. Serum hyaluronan levels increased with the progress of liver disease, particularly in liver cirrhosis. There were no significant differences in serum hyaluronan levels among the cirrhotic patients according to Child's grade. Multivariate analysis showed that the significant independent predictors of serum hyaluronan were serum aspartate aminotransferase (P = 0.020), serum alanine aminotransferase (P = 0.008), serum cholinesterase (P < 0.001), particularly serum type IV collagen 7S domain (P < 0.0001), and the histological degree of liver fibrosis (P < 0.0001). These findings suggest that elevated serum hyaluronan levels are closely related to the severity of liver fibrosis. We assessed the predictive value of serum hyaluronan in differentiating cirrhosis from chronic hepatitis, constructing receiver operating curves; we found that serum hyaluronan was a better test for diagnosing cirrhosis than serum type IV collagen 7S domain and laboratory liver tests.

Serum type III procollagen peptide, type IV collagen 7S domain, central triple-helix of type IV collagen and tissue inhibitor of metalloproteinases in patients with chronic viral liver disease: relationship to liver histology

To assess the clinical value of serum biochemical markers, the aminoterminal peptide of type III procollagen, type IV collagen 7S domain, the central triple-helix of type IV collagen and tissue inhibitor of metalloproteinases, as a marker of hepatic fibrosis, we measured these four serum markers in 132 patients with chronic viral liver disease and compared these serum markers with liver histological findings. Serum levels of these markers increased closely with the progress of liver disease, and the abnormal percentages of type III procollagen peptide, type IV collagen 7S domain, central triple-helix of type IV collagen and tissue inhibitor of metalloproteinases in patients with cirrhosis were 97%, 95%, 83% and 48%, respectively. These four serum markers strongly correlated with the histological degree of periportal with or without bridging hepatocellular necrosis and of liver fibrosis and correlated weakly with the degree of intralobular degeneration and focal necrosis and the degree of portal inflammation. The correlation coefficients of serum type IV collagen 7S domain with periportal with or without bridging hepatocellular necrosis and with liver fibrosis were the highest among these four serum markers, suggesting that serum type IV collagen 7S domain is the most valuable diagnostic marker to assess the degree of liver fibrosis in chronic viral liver disease. When we assessed the ability of each serum marker to detect cirrhosis with a receiver operating curve, the best test was type IV collagen 7S domain, and the second best was type III procollagen peptide.(ABSTRACT TRUNCATED AT 250 WORDS)

The source and possible significance of hyaluronan in the peritoneal cavity

The levels of hyaluronan (HA) were determined in dialysate from patients receiving CAPD. The levels found after the four hour dwell were 0.162 +/- 0.08 micrograms/ml (N = 16) in non-infected fluid and 1.69 +/- 1.12 (N = 5) during peritonitis, P < 0.0025. Similarly concentrations in overnight (8 to 10 hours) dwell dialysate were 0.384 +/- 0.22 micrograms/ml (N = 13) when uninfected and 3.17 +/- 2.28 (N = 8) during peritonitis, P < 0.0002. Following de novo catheter insertion the initial peritoneal washout yielded HA levels of 0.0032 +/- 0.0018 micrograms/ml (N = 7). In vitro human peritoneal cells synthesized HA, 90% of which was secreted into the culture medium (CM). By dissociative gel permeation chromatography on Sephacryl 1000 there were no significant differences in the molecular size of HA extracted from (a) non-infected fluid, (b) infected fluid and (c), mesothelial cell culture medium. These results indicate that the process of CAPD results in an increase in HA levels in the peritoneal cavity. During episodes of peritonitis these functions are further augmented. The likely source of HA in the dialysate is the peritoneal mesothelial cells. This response may be an initial event in wound repair.

Relationship between procollagen III aminoterminal propeptide and hyaluronan serum levels and histological fibrosis in primary biliary cirrhosis and chronic viral hepatitis C

The diagnostic values of aminoterminal propeptide of type III procollagen and hyaluronan serum levels were compared as markers of liver fibrosis in two chronic liver diseases of different etiologies and pathophysiologies, namely primary biliary cirrhosis and chronic viral hepatitis C. The results were analysed in terms of the histological extent of fibrosis. Both serum procollagen-III peptide and hyaluronan were elevated in patients with primary biliary cirrhosis and chronic viral hepatitis C (p < 0.0001) relative to control values. A positive correlation was found between serum procollagen-III peptide levels and the histological grade of fibrosis in primary biliary cirrhosis (p < 0.001) but not in chronic viral hepatitis C, while a strong correlation was found between serum hyaluronan levels and histological fibrosis in both primary biliary cirrhosis and chronic viral hepatitis C (p < 0.001), independent of age. These results suggest that, in chronic liver diseases, serum hyaluronan levels could be an important indicator of the extent of fibrosis and should be assayed to monitor the response to treatment in controlled clinical trials.

Predictive factors in ursodeoxycholic acid-treated patients with primary biliary cirrhosis: role of serum markers of connective tissue

The aim of this study was to define factors predictive of the onset of the terminal phase, defined by hyperbilirubinemia or the occurrence of a severe clinical complication, in patients with primary biliary cirrhosis treated with ursodeoxycholic acid. The 97 primary biliary cirrhosis patients in this study participated in a 2-yr clinical trial. Four of the 49 patients treated with ursodeoxycholic acid (13 to 15 mg/kg/day) entered the terminal phase of the disease, compared with 9 of the 48 patients assigned to placebo. In addition to clinical, conventional biological and histological parameters, we analyzed three serum markers of connective tissue components--type III procollagen aminoterminal peptide, hyaluronic acid and laminin. In the ursodeoxycholic acid-treated group, hyaluronic acid, type III procollagen aminoterminal peptide, bilirubin and splenomegaly were the factors most closely associated with entry into the terminal phase of the disease. In multivariate analysis, after adjustment for age, the hyaluronic acid level was the only predictive factor. In the placebo-treated group, the bilirubin level, total bile acid level, Mayo score, type III procollagen aminoterminal peptide, hyaluronic acid, splenomegaly and pruritus were associated with aggravation of disease. In multivariate analysis, high bilirubin level, high type III procollagen aminoterminal peptide or hyaluronic acid levels and low prothrombin time independently implied poor prognosis. In conclusion, when patients with primary biliary cirrhosis are treated with ursodeoxycholic acid, bilirubinemia loses, in part, its predictive value. It is replaced by hyaluronic acid and type III procollagen aminoterminal peptide. This suggests that models used in deciding on the need for liver transplantation require adaptation for patients receiving ursodeoxycholic acid.

Serum hyaluronan and aminoterminal propeptide of type III procollagen: variation with age

The serum levels of hyaluronan and the aminoterminal propeptide of Type III procollagen (PIIINP) were compared in 585 healthy individuals as a function of age. Newborn children displayed high hyaluronan (695 +/- 634 micrograms l-1, mean +/- SD) and PIIINP (295 +/- 152 micrograms l-1) values. The values were not correlated to the gestational week in which the children were born or to the birth weight but there was a significant correlation (p < 0.05) between the hyaluronan and PIIINP levels. During the first year the levels dropped and in childhood (1-16 years of age) both hyaluronan and PIIINP levels were fairly constant at 27 +/- 16 and 22 +/- 8.4 micrograms l-1, respectively. The PIIINP level showed a marked drop in adults compared to children. The drop continued to about 50 years of age (6.5 +/- 2.2 micrograms l-1) and then there was a slight increase in elderly people. The hyaluronan showed a continued increase with age from the level at 16 years of 29 +/- 17 micrograms l-1 to a mean value of 177 +/- 133 micrograms l-1 in people over 75 years. There was no increase in serum hyaluronan in women during pregnancy but the PIINP level increased in the later part of the gestational period. There was no correlation between the serum values of hyaluronan and PIIINP when compared throughout the life span which indicates that the blood levels of the two markers are regulated by independent factors.