Mechanisms by which food intake elevates circulating levels of hyaluronan in humans

Clinical validation of preoperative serum markers for liver fibrosis in living donor liver transplantation recipients

PURPOSE

To validate the reliability of fibrosis markers as predictors of graft survival in living donor liver transplantation (LDLT) recipients.

METHODS

We reviewed data retrospectively, from 163 patients who underwent adult LDLT with preoperative measurements of type IV collagen (CIV), Mac-2 binding protein glycosylation isomer (M2BPGi), and hyaluronic acid (HA). Patients were divided into high and low groups for each biomarker, based on optimal cutoff values, and graft loss within 6 months was evaluated in each group.

RESULTS

The high CIV level group showed significantly lower 6-month graft survival rates and significantly higher rates of postoperative sepsis and sepsis from pneumonia. However, the groups with high and low M2BPGi levels and those with high and low HA levels did not show significant differences in 6-month graft survival rates or rates of postoperative sepsis. Multivariate analysis revealed that a CIV level ≥ 590 was a significant predictor of graft loss within 6 months, postoperative sepsis, and sepsis from pneumonia.

CONCLUSION

Unlike other fibrosis markers, preoperative CIV levels can predict graft survival, postoperative sepsis, and sepsis from pneumonia after LDLT.

Subclinical synovial proliferation in patients with severe haemophilia A: The value of ultrasound screening and biochemical markers

AIM

Subclinical bleeding and inflammation play a role in progression of haemophilic arthropathy. Synovial proliferation is predictive of joint bleeding and its early detection may guide treatment changes and prevent arthropathy progression. This study evaluated the prevalence of active and inactive subclinical synovial proliferation and investigated potential biochemical blood/urine markers to identify patients with active subclinical synovial proliferation.

METHODS

This cross-sectional study included patients with severe haemophilia A born 1970-2006 who were evaluated during routine clinic visits. Patients with (a history of) inhibitors or recent joint bleeding were excluded. Elbows, knees and ankles were examined for subclinical synovial proliferation by ultrasound and physical examination. Active synovial proliferation was distinguished from inactive synovial proliferation using predefined criteria. Blood/urine biochemical markers (serum osteopontin, sVCAM-1, Coll2-1, COMP, CS846, TIMP, and urinary CTX-II) were compared individually and as combined indexes between patients with and without active synovial proliferation.

RESULTS

This cohort consisted of 79 patients with a median age of 31 years (range 16.5-50.8 years) with 62/79 (78%) of the patients using continuous prophylaxis. The annualized joint bleeding rate over the last 5 years was .6 (.2-1.1). Active (17/79, 22%) and inactive subclinical synovial proliferation (17/79, 22%) were both prevalent in this cohort. Biochemical markers were not correlated with active subclinical synovial proliferation.

CONCLUSION

Subclinical synovial proliferation, both active and inactive, was prevalent in patients with severe haemophilia A with access to prophylaxis and would be overlooked without routinely performed ultrasounds. Biochemical markers were unable to identify patients with active subclinical synovial proliferation.

Liver fibrosis in children: a comprehensive review of mechanisms, diagnosis, and therapy

Chronic liver disease incidence is increasing among children worldwide due to a multitude of epidemiological changes. Most of these chronic insults to the pediatric liver progress to fibrosis and cirrhosis to different degrees. Liver and immune physiology differs significantly in children from adults. Because most of pediatric liver diseases have no definitive therapy, a better understanding of population and disease-specific fibrogenesis is mandatory. Furthermore, fibrosis development has prognostic significance and often guide treatment. Evaluation of liver fibrosis continues to rely on the gold-standard liver biopsy. However, many high-quality studies put forward the high diagnostic accuracy of numerous diagnostic modalities in this setting. Herein, we summarize and discuss the recent literature on fibrogenesis with an emphasis on pediatric physiology along with a detailed outline of disease-specific signatures, noninvasive diagnostic modalities, and the potential for antifibrotic therapies.

Noninvasive Fibrosis Testing in Chronic Liver Disease Including Caveats

Assessment of liver fibrosis is important as the range of liver disease management has expanded, rendering biopsy both imperfect and impractical in many situations. Noninvasive tests of fibrosis leverage laboratory, imaging and elastography techniques to estimate disease extent, often with the goal of identifying advanced fibrosis. This review attempts to summarize their utility across a broad range of possible clinical scenarios while considering the central tenets of health care quality: access, quality, and cost. For each test, it also discusses the caveats whereby each test may have reduced effectiveness and how to consider each in a typical clinical setting.

Low plasma hyaluronan is associated with faster functional decline in patients with amyotrophic lateral sclerosis

Objective: Hyaluronan, a glycosaminoglycan that forms a major constituent of the extracellular matrix, has been shown to be increased in the serum of patients with amyotrophic lateral sclerosis (ALS) with longer disease duration. We sought to determine whether measures of venous hyaluronan may serve as a predictive marker for disease progression in patients with ALS. Methods: Sixty-two patients with ALS, and 59 healthy control participants provided a plasma sample for the assessment of hyaluronan. Hyaluronan was compared against functional measures of disability, disease progression, and survival. Results: Hyaluronan was lower in patients with ALS when compared to healthy controls. Plasma hyaluronan was positively correlated with the change in the revised ALS functional rating scale, ΔFRS. Hyaluronan was also found to improve the prognostic power of the ΔFRS. Conclusion: Hyaluronan may serve as a predictive marker for functional decline in patients with ALS. Longitudinal studies are needed to fully explore the prognostic value of hyaluronan as a biomarker for disease progression, and to improve our understanding of components of the extracellular matrix specific to the pathophysiology of ALS.

Adipose tissue hyaluronan production improves systemic glucose homeostasis and primes adipocytes for CL 316,243-stimulated lipolysis

Plasma hyaluronan (HA) increases systemically in type 2 diabetes (T2D) and the HA synthesis inhibitor, 4-Methylumbelliferone, has been proposed to treat the disease. However, HA is also implicated in normal physiology. Therefore, we generated a Hyaluronan Synthase 2 transgenic mouse line, driven by a tet-response element promoter to understand the role of HA in systemic metabolism. To our surprise, adipocyte-specific overproduction of HA leads to smaller adipocytes and protects mice from high-fat-high-sucrose-diet-induced obesity and glucose intolerance. Adipocytes also have more free glycerol that can be released upon beta3 adrenergic stimulation. Improvements in glucose tolerance were not linked to increased plasma HA. Instead, an HA-driven systemic substrate redistribution and adipose tissue-liver crosstalk contributes to the systemic glucose improvements. In summary, we demonstrate an unexpected improvement in glucose metabolism as a consequence of HA overproduction in adipose tissue, which argues against the use of systemic HA synthesis inhibitors to treat obesity and T2D.

Usefulness of serum hyaluronic acid levels as a predictor of incidence of hand osteoarthritis analyzed by longitudinal analysis from the Iwaki cohort

The factors predicting hand osteoarthritis (HOA) in patients remain unknown. We aimed to investigate the usefulness of serum hyaluronic acid (sHA) levels in predicting HOA progression from a 6-year longitudinal epidemiological study. A total of 417 participants in the Iwaki cohort were followed-up over 6 years. Hand and knee radiographs taken at baseline and follow-up were scored according to Kellgren–Lawrence grades and Kallman score. Participants were classified into the HOA group and the non-HOA group. sHA levels at baseline were determined by ELISA. Correlations between sHA levels, the number of involved joints, and Kallman score were estimated. Factors related to the incidence or progression of HOA over 6 years were analyzed. The prevalence of HOA was 19.9% at baseline, and 3.6 ± 2.1 joints were involved. sHA levels in the HOA group at baseline were significantly higher than in the non-HOA group (p < 0.001) and correlated with the number of involved joints (r = 0.399, p < 0.001) and Kallman score (r = 0.540, p < 0.001). The incidence rate was 14.5%, and the progression rate was 46.1% over 6 years. Higher sHA levels at baseline were the risk factor of HOA incidence. Thus, sHA levels predicted the incidence of HOA over 6 years.

Serum hyaluronic acid, a marker for improved liver perfusion after gradual surgical attenuation of extrahepatic portosystemic shunt closure in dogs

Current liver function tests used in dogs do not consistently normalise after successful surgical attenuation of portosystemic shunts (PSS). Serum hyaluronic acid (sHA) concentrations in dogs with PSS are reported to be higher at diagnosis than in healthy dogs. The objective of this study was to assess sHA as a marker of liver perfusion by measuring sHA concentrations in dogs before and after gradual surgical attenuation of extrahepatic (EH)PSS and by determining whether sHA concentrations could differentiate closed EHPSS from persistent shunting. Specificity of sHA was assessed by comparing sHA concentrations in dogs with EHPSS to those in dogs with other liver diseases. Twenty dogs with EHPSS had sHA concentrations measured at diagnosis, 1, 3, and 6 months postoperatively. In addition, sHA concentrations were determined in 10 dogs with other liver diseases. At EHPSS diagnosis, median sHA concentration was 335.6 ng/mL (43.0-790.7 ng/mL). All dogs had a significant decrease in sHA concentrations from 1 month postoperatively onwards (P < 0.05), regardless of surgical outcome. At all postoperative follow-up visits, there was a significant difference between the median sHA concentration in dogs with closed EHPSS vs. those with persistent shunting (P < 0.05). Median sHA concentration in dogs with other liver diseases was 89.8 ng/mL (22.9-160.0 ng/mL), which was significantly lower than dogs with EHPSS at diagnosis (P < 0.001). In conclusion, sHA is a promising non-invasive biomarker that can help to determine liver perfusion after surgical attenuation of EHPSS. In addition, sHA could potentially be used to differentiate dogs with EHPSS from dogs with other liver diseases.

Transfer of orally administered hyaluronan to the lymph

Hyaluronan (HA) has been widely used in medicines, cosmetics and supplements for health and beauty maintenance. Oral administration is the most desirable and convenient means for consumers. The intestine plays an important role in immune system. We hypothesized that orally administered HA would be transferred to both blood and lymph. In this study, we investigated how orally administered HA was absorbed from the gastrointestinal tract and how much HA was incorporated. Four HA formulations, HA-2,000, 8,000, 50,000 and 300,000, were administered to rats, and concentrations of HA in blood and lymph were determined. In the HA-2,000 group, the HA plasma concentration increased after oral administration. The highest lymph concentration of HA was also obtained by administration of HA-2,000. The plasma and lymph concentrations slightly increased after oral administration in the HA-8,000 group. On the other hand, little absorption was found in the HA-50,000 and 300,000 groups. It is speculated that smaller molecules of HA are more easily absorbed. HA-2,000 was absorbed mainly through the portal vein and through the lymph in gastrointestinal absorption. This is the first report showing that HAs, large molecular weight and water-soluble molecules, after oral administration are transferred not only into blood but also into lymph.

Limitations of non-invasive tests for assessment of liver fibrosis

The diagnostic assessment of liver injury is an important step in the management of patients with chronic liver disease (CLD). Although liver biopsy is the reference standard for the assessment of necroinflammation and fibrosis, the inherent limitations of an invasive procedure, and need for repeat sampling, have led to the development of several non-invasive tests (NITs) as alternatives to liver biopsy. Such non-invasive approaches mostly include biological (serum biomarker algorithms) or physical (imaging assessment of tissue stiffness) assessments. However, currently available NITs have several limitations, such as variability, inadequate accuracy and risk factors for error, while the development of a newer generation of biomarkers for fibrosis may be limited by the sampling error inherent to the reference standard. Many of the current NITs were initially developed to diagnose significant fibrosis in chronic hepatitis C, subsequently refined for the diagnosis of advanced fibrosis in patients with non-alcoholic fatty liver disease, and further adapted for prognostication in CLD. An important consideration is that despite their increased use in clinical practice, these NITs were not designed to reflect the dynamic process of fibrogenesis, differentiate between adjacent disease stages, diagnose non-alcoholic steatohepatitis, or follow longitudinal changes in fibrosis or disease activity caused by natural history or therapeutic intervention. Understanding the strengths and limitations of these NITs will allow for more judicious interpretation in the clinical context, where NITs should be viewed as complementary to, rather than as a replacement for, liver biopsy.

Role of serum M2BPGi levels on diagnosing significant liver fibrosis and cirrhosis in treated patients with chronic hepatitis B virus infection

Background

Mac-2-binding protein glycosylation isomer (M2BPGi), a novel serum marker for liver fibrosis, was seldom studied in chronic hepatitis B (CHB). We aimed to evaluate its role on diagnosing significant fibrosis and cirrhosis in treated CHB patients.

Methods

CHB patients treated with nucleos(t)ide analogues (NAs) with baseline liver biopsies and retrievable serum samples were recruited. Paired liver biopsies were performed in patient subgroups at 1 and 3 years.

Results

In total, 327 NA-treated CHB patients (M:F = 229:98; median age 38.1 years) were recruited. The median M2BPGi values were 0.26, 0.34, 0.57 and 1.21 cutoff index (COI), in liver histology with Ishak F0–1, F2, F3 and F4, respectively (p < 0.01). M2BPGi levels correlated with the Ishak scores (ρ = 0.312, p < 0.001). Using the cutoff values of 0.25, 0.45 and 0.96 COI for ≥F2, ≥F3 and F4, the AUROCs were 0.653, 0.795 and 0.914, respectively. Multivariate analysis with several other serum indices showed that M2BPGi was the most significant independent factor for ≥F3 (OR: 8.197, 95% CI: 2.699–24.897, p < 0.001). In patient subgroups with serial liver biopsies, both the proportion of F3/F4 and M2BPGi decreased at 1 year (8.3% vs. 2.8% and 0.32 vs. 0.21 COI, respectively; both p < 0.001). Histological fibrosis progression after ≥3 years of NA therapy accompanied with an increase in M2BPGi level, compared to patients without progression (+0.14 vs −0.03 COI, p = 0.045).

Conclusion

Serum M2BPGi is a reliable non-invasive marker for diagnosing ≥F2, ≥F3 and F4. It is the only significant marker for ≥F3 among several other indices. NA produced concordant dynamic changes in M2BPGi levels and histological fibrosis.

Association of Mac-2-binding protein glycosylation isomer level with nutritional status in chronic liver disease

BACKGROUND AND AIM

Mac-2-binding protein glycosylation isomer (M2BPGi) was recently identified as a serum glycobiomarker for liver fibrosis. However, the relationship between M2BPGi and malnutrition in patients with chronic liver disease (CLD) is unknown. We aimed to evaluate whether M2BPGi could be a surrogate marker for malnutrition in patients with CLD.

METHODS

In total, 338 outpatients with CLD were enrolled (median age: 67 years). We evaluated the associations among liver fibrosis markers (M2BPGi, fibrosis-4 index, and aspartate aminotransferase-to-platelet count ratio index), Child-Pugh stages, and nutritional status markers.

RESULTS

The median value (range) of serum M2BPGi levels was 0.94 cut-off index (COI) (0.22-11.57) in chronic hepatitis and Child-Pugh A (n = 274), 4.775 COI (1.32-16.68) in Child-Pugh B (n = 46), and 11.37 COI (6.03-18.33) in Child-Pugh C (n = 18) (overall significance, P < 0.001). Serum M2BPGi levels showed a strong correlation with serum albumin concentration and controlling nutritional status score (rs  = -0.649, P < 0.001 and rs  = 0.671, P < 0.001, respectively). The correlations between M2BPGi and nutritional status markers were especially high in patients with hepatitis C virus infection and non-B non-C hepatitis and patients with hepatocellular carcinoma. Among the three fibrosis markers, M2BPGi yielded the highest area under the receiver operating characteristic curve (0.920) for predicting hypoalbuminemia at an optimal cut-off value of 2.41 (sensitivity, 87.3%; specificity, 87.6%; P < 0.001).

CONCLUSIONS

Serum M2BPGi levels are correlated with nutritional status markers in patients with CLD and could be a useful clinical marker of malnutrition.

Study of FibroTest and hyaluronic acid biological variation in healthy volunteers and comparison of serum hyaluronic acid biological variation between chronic liver diseases of different etiology and fibrotic stage using confidence intervals

OBJECTIVES

Personalized ranges of liver fibrosis serum biomarkers such as FibroTest or hyaluronic acid could be used for early detection of fibrotic changes in patients with progressive chronic liver disease. Our aim was to generate reliable biological variation estimates for these two biomarkers with confidence intervals for within-subject biological variation and reference change value.

DESIGN AND METHODS

Nine fasting healthy volunteers and 66 chronic liver disease patients were included. Biological variation estimates were calculated for FibroTest in healthy volunteers, and for hyaluronic acid in healthy volunteers and chronic liver disease patients stratified by etiology and liver fibrosis stage.

RESULTS

In healthy volunteers, within-subject biological coefficient of variation (with 95% confidence intervals) and index of individuality were 20% (16%-28%) and 0.6 for FibroTest and 34% (27%-47%) and 0.79 for hyaluronic acid, respectively. Overall hyaluronic acid within-subject biological coefficient of variation was similar among non-alcoholic fatty liver disease and chronic hepatitis C with 41% (34%-52%) and 45% (39%-55%), respectively, in contrast to chronic hepatitis B with 170% (140%-215%). Hyaluronic acid within-subject biological coefficients of variation were similar between F0-F1, F2 and F3 liver fibrosis stages in non-alcoholic fatty liver disease with 34% (25%-49%), 41% (31%-59%) and 34% (23%-62%), respectively, and in chronic hepatitis C with 34% (27%-47%), 33% (26%-45%) and 38% (27%-65%), respectively. However, corresponding hyaluronic acid indexes of individuality were lower in the higher fibrosis stages.

CONCLUSION

Non-overlapping confidence intervals of biological variation estimates allowed us to detect significant differences regarding hyaluronic acid biological variation between chronic liver disease subgroups.

Gene expression in salivary glands: effects of diet and mouse chromosome 17 locus regulating macronutrient intake

Dcpp2, Prrt1, and Has1 are plausible candidate genes for the Mnic1 (macronutrient intake-carbohydrate) locus on mouse chromosome 17, based on their map positions and sequence variants, documented expression in salivary glands, and the important role of saliva in oral food processing and taste. We investigated the effects of genotype and diet on gene expression in salivary glands (parotid, submandibular, sublingual) of carbohydrate-preferring, C57BL6J.CAST/EiJ-17.1 subcongenic mice compared to fat-preferring wild-type C57BL/6J. To achieve accurate normalization of real-time quantitative RT-PCR data, we evaluated multiple reference genes to identify the most stably expressed control genes in salivary gland tissues, and then used geometric averaging to produce a reliable normalization factor. Gene expression was measured in mice fed different diets: (1) rodent chow, (2) macronutrient selection diets, (3) high-fat diet, and (4) low-fat diet. In addition, we measured salivary hyaluronan concentrations. All three genes showed strain differences in expression, in at least one major salivary gland, and diet effects were observed in two glands. Dcpp2 expression was limited primarily to sublingual gland, and strongly decreased in B6.CAST-17.1 subcongenic mice compared to wild-type B6, regardless of diet. In contrast, both genotype and diet affected Prrt1 and Has1 expression, in a gland-specific manner, for example, Prrt1 expression in the parotid gland alone was strongly reduced in both mouse strains when fed macronutrient selection diet compared to chow. Notably, we discovered an association between diet composition and salivary hyaluronan content. These results demonstrate robust effects of genetic background and diet composition on candidate gene expression in mouse salivary glands.

Associations between biomarkers of joint metabolism, hand osteoarthritis, and hand pain and function: the Johnston County Osteoarthritis Project

OBJECTIVE

To determine the associations between joint metabolism biomarkers and hand radiographic osteoarthritis [(rOA), based on Kellgren Lawrence (KL) grade ≥ 2], symptoms, and function.

METHODS

Cross-sectional data were available for 663 participants (mean age 63 yrs, 63% white, 49% women). Three definitions of hand rOA were considered: (1) a composite measure involving at least 3 hand joints distributed bilaterally with 2 of 3 in the same joint group, including ≥ 1 distal interphalangeal joint, without metacarpophalangeal (MCP) swelling; (2) rOA in at least 1 joint of a group; and (3) number of joints with KL ≥ 2. We assessed hand symptoms and the 15-item Australian Canadian Hand Osteoarthritis Index (AUSCAN; Likert format). We measured serum cartilage oligomeric matrix protein (sCOMP), hyaluronic acid (sHA), carboxy-terminal propeptide of type II collagen, type II collagen degradation product, urinary C-terminal crosslinked telopeptide of type II collagen, and urinary N-terminal crosslinked telopeptide. Linear regression models were performed to assess associations between each biomarker with hand rOA, AUSCAN, and symptoms, adjusting for age, sex, race, current smoking/drinking status, body mass index, and hip and knee rOA.

RESULTS

In adjusted analyses, MCP (p < 0.0001) and carpometacarpal rOA (p = 0.003), and a higher number of hand joints with rOA (p = 0.009), were associated with higher levels of sHA. Positive associations were seen between AUSCAN and hand symptoms and levels of sCOMP (p ≤ 0.003) and sHA (p ≤ 0.048).

CONCLUSION

Hand symptoms and higher AUSCAN scores were independently associated with higher levels of both sCOMP and sHA; hand rOA was associated only with sHA levels.

Increased incidence of antiretroviral drug discontinuation among patients with viremic hepatitis C virus coinfection and high hyaluronic acid, a marker of liver fibrosis

BACKGROUND

Most antiretroviral drugs are metabolized by the liver; hepatic disease or liver damage as a result of hepatitis C virus (HCV) could impair this metabolism leading to an increased risk of drug toxicity. This study aimed to determine the risk of antiretroviral drug discontinuation among HCV/HIV coinfected patients.

METHODS

EuroSIDA patients taking combination antiretroviral therapy were included. Poisson regression identified factors associated with antiretroviral treatment discontinuation.

RESULTS

A total of 9535 HIV-positive patients with known HCV status were included (6939 HCVAb-negative; 2596 HCVAb-positive at baseline). Viremic HCV infection was associated with a 44% increased risk of antiretroviral drug discontinuation compared with aviremic infection [adjusted incidence rate ratio, aIRR: 1.44 (95% confidence interval, CI 1.22-1.69)]; this relationship was largest among nonnucleoside reverse transcriptase inhibitors [aIRR: 1.59 (95% CI 1.18-2.14)]. In the subset of 935 HIV-positive patients also HCV-positive or HBV-positive with plasma hyaluronic acid measured, hyaluronic acid more than 100 ng/ml was associated with a 37% increased risk of antiretroviral drug discontinuation [aIRR: 1.37 (95% CI 1.08-1.73) vs. hyaluronic acid ≤100 ng/ml] and the effect of HCV viremia became nonsignificant; the largest drug association was seen for protease inhibitors [aIRR: 1.40 (95% CI 1.04-1.89)].

CONCLUSION

HCV viremia and high levels of hyaluronic acid predict antiretroviral drug discontinuation. Evidence was also found to suggest a link between impaired liver function and protease inhibitor toxicity.

Ultrasonography (US) and non-invasive diagnostic methods for non-alcoholic fatty liver disease (NAFLD) and early vascular damage. Possible application in a population study on the metabolic syndrome (MS)

Abdominal ultrasonography (US) represents the first-line imaging examination in chronic liver diseases; in most cases, US, laboratory findings and the clinical context are generally sufficient to guide the diagnosis. Thanks to the considerable diffusion of US, we have seen an increased diagnosis of NAFLD in recent years, although this condition is generally silent from a clinical point of view. We have to identify the metabolic syndrome in the general population and to promptly recognize NAFLD to prevent its development into non-alcoholic steatohepatitis, cirrhosis and hepatocellular carcinoma. Among the non-invasive diagnostic techniques for NAFLD and for early vascular damage, ultrasonography represents the method of choice. In fact, besides the traditional semiotics of fundamental US of the liver, new US techniques have recently been proposed (contrast enhancement US, acoustic structure characterization), with respect to serum biomarkers and Fibroscan, for the study of liver fibrosis. Similarly, also as concerns the US measurement of carotid intima-media thickness, new automated methods with sophisticated software and radio-frequency signal have recently been introduced. Finally, we report the preliminary results of a personal experience on liver and carotid US in the epidemiology of the metabolic syndrome.

Molecular serum markers of liver fibrosis

Fibrosis is a hallmark histologic event of chronic liver diseases and is characterized by the excessive accumulation and reorganization of the extracellular matrix (ECM). The gold standard for assessment of fibrosis is liver biopsy. As this procedure has various limitations, including risk of patient injury and sampling error, a non-invasive serum marker for liver fibrosis is desirable. The increasing understanding of the pathogenesis of hepatic fibrosis has suggested several markers which could be useful indicators of hepatic fibrogenesis and fibrosis. These markers include serum markers of liver function, ECM synthesis, fibrolytic processes, ECM degradation and fibrogenesis related cytokines. Recently, neo-epitopes, which are post-translational modifications of proteins, have been successfully used in bone and cartilage diseases which are characterized by extensive ECM remodeling. Increasing numbers of studies are being undertaken to identify neo-epitopes generated during liver fibrosis, and which ultimately might be useful for diagnosing and monitoring fibrogenesis. To date, the metalloproteinases generated fragment of collagen I, III, IV and VI have been proven to be elevated in two rat models of fibrosis. This review summarizes the recent efforts that have been made to identify potentially reliable non-invasive serum markers. We used the recently proposed BIPED (Burden of disease, Investigative, Prognostic, Efficacy and Diagnostic) system to characterize potential serum markers and neo-epitope markers that have been identified to date.

Invasive and non-invasive methods for the assessment of fibrosis and disease progression in chronic liver disease

Chronic liver diseases represent a major public health problem, accounting for significant morbidity and mortality worldwide. Their prognosis and management greatly depend on the amount and progression of liver fibrosis with the risk of developing cirrhosis. Liver biopsy, traditionally considered as the reference standard for staging of fibrosis, has been challenged over the past decade by the development of novel non invasive methodologies. These methods rely on two distinct but complementary approaches: i) a 'biological' approach based on the dosage of serum biomarkers of fibrosis; ii) a 'physical' approach based on the measurement of liver stiffness using transient elastography (TE). Non invasive methods have been initially studied and validated in chronic hepatitis C but are now increasingly used in other chronic liver diseases, resulting in a significant decrease in the need for liver biopsy. However, they will likely not completely abolish the need for liver biopsy and they should rather be employed as an integrated system with liver biopsy. This review is aimed at discussing the advantages and inconveniences of non invasive methods in comparison with liver biopsy for the management of patients with chronic liver diseases.

Non-invasive assessment of liver fibrosis in chronic hepatitis C

Quantification of hepatic fibrosis is of critical importance in chronic hepatitis C not only for prognosis, but also for antiviral treatment indication. Two end points are clinically relevant: detection of significant fibrosis (indication for antiviral treatment) and detection of cirrhosis (screening for eosphageal varices and hepatocellular carcinoma). Until recently, liver biopsy was considered the reference method for the evaluation of liver fibrosis. Limitations of liver biopsy (invasiveness, sampling error, and inter-observer variability) have led to the development of non-invasive methods. Currently available methods rely on two different approaches: a "biological" approach based on the dosage of serum fibrosis biomarkers; and a "physical" approach based on the measurement of liver stiffness, using transient elastography (TE). This review is aimed at discussing the advantages and limits of non-invasive methods and liver biopsy and the perspectives for their rational use in clinical practice in the management of patients with chronic hepatitis C.

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

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

Genesis of hepatic fibrosis and its biochemical markers

Liver fibrosis is characterized by an abnormal hepatic accumulation of extracellular matrix (ECM) that results from both increased deposition and reduced degradation of collagen fibres. Fibrotic liver injury results in activation of the hepatic stellate cell (HSC). Surrogate markers are gradually being substituted for biomarkers that reflect the complex balance between synthesis and degradation of the extracellular matrix. Once the hepatic stellate cell is activated, the preceding matrix changes and recurrent injurious stimuli will perpetuate the activated state. The ECM directs cellular differentiation, migration, proliferation and fibrogenic activation or deactivation. The metabolism of the extracellular matrix is closely regulated by matrix metalloproteinases (MMP) and their specific tissue inhibitors (TIMP). Although liver biopsy combined with connective tissue stains has been a mainstay of diagnosis, there is a need for less invasive methods. These diagnostic markers should be considered in combination with liver function tests, ultrasonography and clinical manifestations.

Assessing liver fibrosis

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

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.

Predicting effect of food on extent of drug absorption based on physicochemical properties

PURPOSE

To develop a statistical model for predicting effect of food on the extent of absorption (area under the curve of time-plasma concentration profile, AUC) of drugs based on physicochemical properties.

MATERIALS AND METHODS

Logistic regression was applied to establish the relationship between the effect of food (positive, negative or no effect) on AUC of 92 entries and physicochemical parameters, including clinical doses used in the food effect study, solubility (pH 7), dose number (dose/solubility at pH 7), calculated Log D (pH 7), polar surface area, total surface area, percent polar surface area, number of hydrogen bond donor, number of hydrogen bond acceptors, and maximum absorbable dose (MAD).

RESULTS

For compounds with MAD >or= clinical dose, the food effect can be predicted from the dose number category and Log D category, while for compounds with MAD < clinical dose, the food effect can be predicted from the dose number category alone. With cross validation, 74 out of 92 entries (80%) were predicted into the correct category. The correct predictions were 97, 79 and 68% for compounds with positive, negative and no food effect, respectively.

CONCLUSIONS

A logistic regression model based on dose, solubility, and permeability of compounds is developed to predict the food effect on AUC. Statistically, solubilization effect of food primarily accounted for the positive food effect on absorption while interference of food with absorption caused negative effect on absorption of compounds that are highly hydrophilic and probably with narrow window of absorption.