Diagnostic value of serum prolidase enzyme activity to predict the liver histological lesions in non-alcoholic fatty liver disease: a surrogate marker to distinguish steatohepatitis from simple steatosis

Beta vulgaris L. var cicla Decreases Liver Injury Induced by Antiarrhytmic Agent, Amiodarone

Amiodarone (AMD) is an effective antiarrhythmic drug, but its long-term usage strongly forms liver toxicity due to its accumulation tendency. The chard (Beta vulgaris L. var. cicla) is a unique plant which has a blood sugar-lowering effect and powerful antioxidant activity. The aim of the current study was to investigate the possible protective effects of chard on AMD-induced liver injury. Male Sprague-Dawley rats were divided into four groups. Control group, aqueous chard extract given group 500 mg/kg/day for one week, AMD given group 100 mg/kg/day for one week, AMD+Chard given group (at the same doses and times). They were sacrificed on the 8th day. The blood and liver samples were taken. The serum and liver biochemical parameters were found to be changed in AMD treated group. Chard administration reversed these parameters in serum and liver. In histological experiments, necrotic areas, mononuclear cell infiltration, the endothelial rupture in central vein, sinusoidal dilatation, hyperemia, dark eosinophilic cells and picnotic nucleus were observed in liver tissues of AMD treated group. Chard treatment reduced liver tissue damage. Considering results, we can suggest that chard prevented AMD induced liver injury biochemically and histologically.

Chronic Liver Disease in Patients with Prolidase Deficiency: A Case Series

Introduction

Prolidase deficiency is a rare autosomal recessive disorder caused by variants in the PEPD gene. Patients usually have multi-organ involvement and a wide range of clinical features including recurrent skin ulcers, dysmorphic facial features, recurrent infections, intellectual disability, and splenomegaly. Studies have shown that patients with prolidase deficiency may have hepatic manifestations including hepatomegaly and abnormal liver enzymes. However, there is no detailed description of liver disease in this patient population.

Case Presentation

Here, we present 3 patients with prolidase deficiency with varying extents of hepatic involvement.

Conclusion

Prolidase deficiency patients with liver disease should be followed up long term to understand more about the pathophysiology and the impact of liver disease on long-term outcomes.

Advances in Noninvasive Biomarkers for Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) currently represents one of the most common liver diseases worldwide. Early diagnosis and disease staging is crucial, since it is mainly asymptomatic, but can progress to nonalcoholic steatohepatitis (NASH) or cirrhosis or even lead to the development of hepatocellular carcinoma. Over time, efforts have been put into developing noninvasive diagnostic and staging methods in order to replace the use of a liver biopsy. The noninvasive methods used include imaging techniques that measure liver stiffness and biological markers, with a focus on serum biomarkers. Due to the impressive complexity of the NAFLD's pathophysiology, biomarkers are able to assay different processes involved, such as apoptosis, fibrogenesis, and inflammation, or even address the genetic background and "omics" technologies. This article reviews not only the currently validated noninvasive methods to investigate NAFLD but also the promising results regarding recently discovered biomarkers, including biomarker panels and the combination of the currently validated evaluation methods and serum markers.

Prolidase as a marker of fibrogenesis in idiopathic primary ovarian insufficiency

OBJECTIVES

To evaluate the serumlevel of prolidase,which isa marker of fibrogenic activity, in women with idiopathic primary ovarian insufficiency (POI).

STUDY DESIGN

This is a prospective case-control study. Serum prolidase level was compared between the study group including 68 women with POI and control group including 65 normally menstruating women. Serum proline and hydroxyproline levels were also compared. Correlation analyses were performed between the prolidase level and POI related parameters including estradiol (E), follicle stimulating hormone (FSH), anti-mullerian hormone (AMH) levels, and presence of POI family history.

RESULTS

Serum prolidase and proline level were significantly increased in women with the diagnosis of POI compared to the control group (1082.57 (147.53) vs 981.13 (223.26) U/L, 233.30 (83.16) vs 218.94 (82.59) µmol/L, respectively). Prolidase level found to have significant correlations with AMH, E, FSH levels, and presence of POI family history (r = -0.49, p = 0.001; r = -0.39, p = 0.001; r = 0.42, p = 0.001; r = 0.22, p = 0.01; respectively). In receiver operating characteristics analysis, prolidase was shown to be a discriminative factor for POI at 1031.14 U/L cut-off value with 75 % sensitivity and 65 % specificity. Thearea under curve was 0.71 [(95 % CI: 0.62-0.79), p = 0.001].

CONCLUSION

The current study revealed increased prolidase level in women withPOI. Serum prolidase level was also negatively correlated with the serum AMH level. Considering the present findings,prolidase may be a candidate molecule in assessment of POI cases.

Relationship between serum sialic acid levels and prolidase activity with airflow obstruction in patients with COPD

ABSTRACT

Our aim in this study was to evaluate the prognostic significance of sialic acid (SA) and prolidase activity and to evaluate the association between airflow obstruction severity and these parameters in chronic obstructive pulmonary disease (COPD) patients.Ninety-four patients (84 M, 10 F) and 34 healthy subjects (19 M, 15 F) were included into the study. COPD staging was performed to COPD patients according to new global initiative for chronic obstructive lung disease criteria which includes pulmonary function tests, symptoms and hospitalization; COPD patients were divided into 4 subgroups as group A (n = 25), group B (n = 19), group C (n = 20), and group D (n = 28).SA and C-reactive protein levels were significantly higher than the control group in all COPD groups. SA levels were significantly higher in group B patients than the control and group A. Prolidase activity was significantly lower than control group in total COPD groups (P < .05). There was a weak negative correlation between SA and forced vital capacity (r = -0.217, P = .038) and forced expiratory volume in 1 second (FEV1) (r = -0.210, P = .045), whereas weak positive correlation was present between SA and Creactive protein (r = 0.247, P = .018) in all patient groups. There was weak positive correlation between prolidase and FEV1 (r = 0.222, P = .033) and FEV1/forced vital capacity (r = 0.230, P = .027).Our study shows that systemic inflammation, prolidase activity, and SA levels in stable COPD patients are associated with airflow obstruction severity. In addition to the prolidase activity; SA levels might be associated with inflammation.

PROLIDASE: A Review from Discovery to its Role in Health and Disease

Prolidase (peptidase D), encoded by the PEPD gene, is a ubiquitously expressed cytosolic metalloproteinase, the only enzyme capable of cleaving imidodipeptides containing C-terminal proline or hydroxyproline. Prolidase catalyzes the rate-limiting step during collagen recycling and is essential in protein metabolism, collagen turnover, and matrix remodeling. Prolidase, therefore plays a crucial role in several physiological processes such as wound healing, inflammation, angiogenesis, cell proliferation, and carcinogenesis. Accordingly, mutations leading to loss of prolidase catalytic activity result in prolidase deficiency a rare autosomal recessive metabolic disorder characterized by defective wound healing. In addition, alterations in prolidase enzyme activity have been documented in numerous pathological conditions, making prolidase a useful biochemical marker to measure disease severity. Furthermore, recent studies underscore the importance of a non-enzymatic role of prolidase in cell regulation and infectious disease. This review aims to provide comprehensive information on prolidase, from its discovery to its role in health and disease, while addressing the current knowledge gaps.

Serum prolidase level in patients with brucellosis and its possible relationship with pathogenesis of the disease: a prospective observational study

Background/aim

Changes in collagen metabolism and fibroblastic activity may play a role in the pathogenesis of brucellosis. The prolidase enzyme plays an important role in collagen synthesis. We aimed to investigate the association of prolidase levels with brucellosis.

Materials and methods

Serum prolidase levels in 20 patients newly diagnosed with brucellosis were compared with levels in 30 healthy control subjects. Patients with brucellosis were reassessed 3 months later for prolidase, other laboratory measurements, and response to treatment.

Results

The levels of serum prolidase were significantly higher in brucellosis patients compared with those of healthy controls. Prolidase, sedimentation, and C-reactive protein levels were significantly lower after antibrucellosis treatment than before treatment.

Conclusion

The current study is the first to demonstrate significantly increased serum prolidase levels in patients with brucellosis compared with healthy controls. Prolidase levels also significantly decreased with antibrucellosis treatment. This finding provides a new experimental basis to understand the pathogenesis of brucellosis in relation to collagen metabolism. The increase in serum prolidase levels might be related to several factors such as tissue destruction, increased fibroblastic activity, and granuloma formation, all of which are involved in the natural history of brucellosis.

Evaluation of the effect of Lactobacillus reuteri V3401 on biomarkers of inflammation, cardiovascular risk and liver steatosis in obese adults with metabolic syndrome: a randomized clinical trial (PROSIR)

Background

Obesity is characterized by increased fat mass and is associated with the development of insulin resistance syndrome (IRS), usually known as metabolic syndrome. The alteration of the intestinal microbiota composition has a role in the development of IRS associated with obesity, and probiotics, which are live microorganisms that confer a health benefit to the host, contribute to restore intestinal microbiota homeostasis and lower peripheral tissue insulin resistance. We aim to evaluate the effects of the probiotic strain Lactobacillus reuteri (L. reuteri) V3401 on the composition of intestinal microbiota, markers of insulin resistance and biomarkers of inflammation, cardiovascular risk, and hepatic steatosis in patients with overweight and obesity exhibiting IRS.

Methods/design

We describe a randomized, double-blind, crossover, placebo-controlled, and single-centre trial. Sixty participants (aged 18 to 65 years) diagnosed with IRS will be randomized in a 1:1 ratio to receive either a daily dose of placebo or 5 × 10⁹ colony-forming units of L. reuteri V3401. The study will consist of two intervention periods of 12 weeks separated by a washout period of 6 weeks and preceded by another washout period of 2 weeks. The primary outcome will be the change in plasma lipopolysaccharide (LPS) levels at 12 weeks. Secondary outcomes will include anthropometric parameters, lipid profile, glucose metabolism, microbiota composition, hepatic steatosis, and inflammatory and cardiovascular biomarkers. Blood and stool samples will be collected at baseline, at the midpoint (only stool samples) and immediately after each intervention period. Luminex technology will be used to measure interleukins. For statistical analysis, a mixed ANOVA model will be employed to calculate changes in the outcome variables.

Discussion

This is the first time that L. reuteri V3401 will be evaluated in patients with IRS. Therefore, this study will provide valuable scientific information about the effects of this strain in metabolic syndrome patients.

Trial registration

The trial has been retrospectively registered in ClinicalTrials.gov on the 23rd November 2016 (ID: NCT02972567), during the recruitment phase.

Electronic supplementary material

The online version of this article (10.1186/s12906-018-2371-x) contains supplementary material, which is available to authorized users.

Nonalcoholic fatty liver disease: Diagnostic biomarkers

Nonalcoholic fatty liver disease is a common medical condition worldwide and its prevalence has increased notably in the past few years due to the increases in prevalence of obesity and metabolic syndrome. However, diagnosis of this disease is still a matter of debate because of disease variations and pathophysiologic alterations. Specific single markers have gained considerable attention recently, among them markers related to hepatic pathophysiology, inflammation, adipocytokines and so forth. But, it seems that no single marker is sufficient for diagnosis and staging of the disease, and applying a panel including different types of tests may be more useful.

Non-alcoholic fatty liver diseases: update on the challenge of diagnosis and treatment

The prevalence of non-alcoholic fatty liver disease (NAFLD) is estimated to be 25-30% of the population, and is the most common cause of elevated liver enzymes in Korea. NAFLD is a “hot potato” for pharmaceutical companies. Many clinical trials are underway to develop a first-in-class drug to treat NAFLD. However, there are several challenging issues regarding the diagnosis of NAFLD. Currently, liver biopsy is the gold standard method for the diagnosis of NAFLD and steatohepatitis. Ideally, globally recognized standards for histological diagnosis and methods to optimize observer agreement on biopsy interpretation should be developed. Liver biopsy is the best method rather than a perfect one. Recently, multi-parametric magnetic resonance imagery can estimate the amount of intrahepatic fat successfully and is widely used in clinical trials. But no diagnostic method can discriminate between steatohepatitis and simple steatosis. The other unresolved issue in regard to NAFLD is the absence of satisfactory treatment options. Vitamin E and obeticholic acid have shown protective effects in randomized controlled trials, but this drug has not been approved for use in Korea. This study will provide a description of diagnostic methods and treatments that are currently recommended for NAFLD.

Cost-effectiveness of non-invasive methods for assessment and monitoring of liver fibrosis and cirrhosis in patients with chronic liver disease: systematic review and economic evaluation

BACKGROUND

Liver biopsy is the reference standard for diagnosing the extent of fibrosis in chronic liver disease; however, it is invasive, with the potential for serious complications. Alternatives to biopsy include non-invasive liver tests (NILTs); however, the cost-effectiveness of these needs to be established.

OBJECTIVE

To assess the diagnostic accuracy and cost-effectiveness of NILTs in patients with chronic liver disease.

DATA SOURCES

We searched various databases from 1998 to April 2012, recent conference proceedings and reference lists.

METHODS

We included studies that assessed the diagnostic accuracy of NILTs using liver biopsy as the reference standard. Diagnostic studies were assessed using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool. Meta-analysis was conducted using the bivariate random-effects model with correlation between sensitivity and specificity (whenever possible). Decision models were used to evaluate the cost-effectiveness of the NILTs. Expected costs were estimated using a NHS perspective and health outcomes were measured as quality-adjusted life-years (QALYs). Markov models were developed to estimate long-term costs and QALYs following testing, and antiviral treatment where indicated, for chronic hepatitis B (HBV) and chronic hepatitis C (HCV). NILTs were compared with each other, sequential testing strategies, biopsy and strategies including no testing. For alcoholic liver disease (ALD), we assessed the cost-effectiveness of NILTs in the context of potentially increasing abstinence from alcohol. Owing to a lack of data and treatments specifically for fibrosis in patients with non-alcoholic fatty liver disease (NAFLD), the analysis was limited to an incremental cost per correct diagnosis. An analysis of NILTs to identify patients with cirrhosis for increased monitoring was also conducted.

RESULTS

Given a cost-effectiveness threshold of £20,000 per QALY, treating everyone with HCV without prior testing was cost-effective with an incremental cost-effectiveness ratio (ICER) of £9204. This was robust in most sensitivity analyses but sensitive to the extent of treatment benefit for patients with mild fibrosis. For HBV [hepatitis B e antigen (HBeAg)-negative)] this strategy had an ICER of £28,137, which was cost-effective only if the upper bound of the standard UK cost-effectiveness threshold range (£30,000) is acceptable. For HBeAg-positive disease, two NILTs applied sequentially (hyaluronic acid and magnetic resonance elastography) were cost-effective at a £20,000 threshold (ICER: £19,612); however, the results were highly uncertain, with several test strategies having similar expected outcomes and costs. For patients with ALD, liver biopsy was the cost-effective strategy, with an ICER of £822.

LIMITATIONS

A substantial number of tests had only one study from which diagnostic accuracy was derived; therefore, there is a high risk of bias. Most NILTs did not have validated cut-offs for diagnosis of specific fibrosis stages. The findings of the ALD model were dependent on assuptions about abstinence rates assumptions and the modelling approach for NAFLD was hindered by the lack of evidence on clinically effective treatments.

CONCLUSIONS

Treating everyone without NILTs is cost-effective for patients with HCV, but only for HBeAg-negative if the higher cost-effectiveness threshold is appropriate. For HBeAg-positive, two NILTs applied sequentially were cost-effective but highly uncertain. Further evidence for treatment effectiveness is required for ALD and NAFLD.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42011001561.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Assessment of the correlation between serum prolidase and alpha-fetoprotein levels in patients with hepatocellular carcinoma

AIM: To determine the predictive value of increased prolidase activity that reflects increased collagen turnover in patients with hepatocellular carcinoma (HCC).

METHODS: Sixty-eight patients with HCC (mean age of 69.1 ± 10.1), 31 cirrhosis patients (mean age of 59.3 ± 6.3) and 33 healthy volunteers (mean age of 51.4 ± 12.6) were enrolled in this study. Univariate and multivariate analysis were used to evaluate the association of serum α-fetoprotein (AFP) values with HCC clinicopathological features, such as tumor size, number and presence of vascular and macrovascular invasion. The patients with HCC were divided into groups according to tumor size, number and presence of vascular invasion (diameters; ≤ 3 cm, 3-5 cm and ≥ 5 cm, number; 1, 2 and ≥ 3, macrovascular invasion; yes/no). Barcelona-clinic liver cancer (BCLC) criteria were used to stage HCC patients. Serum samples for measurement of prolidase and alpha-fetoprotein levels were kept at -80 °C until use. Prolidase levels were measured spectrophotometrically and AFP concentrations were determined by a chemiluminescence immunometric commercial diagnostic assay.

RESULTS: In patients with HCC, prolidase and AFP values were evaluated according to tumor size, number, presence of macrovascular invasion and BCLC staging classification. Prolidase values were significantly higher in patients with HCC compared with controls (P < 0.001). Prolidase levels were significantly associated with tumor size and number (P < 0.001, P = 0.002, respectively). Prolidase levels also differed in patients in terms of BCLC staging classification (P < 0.001). Furthermore the prolidase levels in HCC patients showed a significant difference compared with patients with cirrhosis (P < 0.001). In HCC patients grouped according to tumor size, number and BCLC staging classification, AFP values differed separately (P = 0.032, P = 0.038, P = 0.015, respectively). In patients with HCC, there was a significant correlation (r = 0.616; P < 0.001) between prolidase and AFP values in terms of tumor size, number and BCLC staging classification, whereas the presence of macrovascular invasion did not show a positive association with serum prolidase and AFP levels.

CONCLUSION: Considering the levels of both serum prolidase and AFP could contribute to the early diagnosing of hepatocellular carcinoma.

Prolidase activity in chronic plaque psoriasis patients

INTRODUCTION

Psoriasis is a chronic, inflammatory, T-cell-mediated and hyperproliferative skin disease characterized by erythematous, squamous, sharply circumscribed and infiltrated plaques. The metabolisms of the collagen proteins undergo considerable changes due to the acceleration of their turnovers as a result of increased prolidase activity in psoriasis patients.

AIM

To determine the level of prolidase activity in psoriasis patients and evaluate its relationship with the oxidative system.

MATERIAL AND METHODS

The serum prolidase enzyme activity, total antioxidant levels and total oxidant levels of 40 psoriasis patients and a control group including 47 healthy individuals were analyzed by using their serum samples, and their oxidative stress indices were calculated.

RESULTS

The prolidase levels (p < 0.01), total oxidant levels (p < 0.01) and oxidative stress index levels (p < 0.001) of the patient group were higher than the corresponding parameters in the control group. The total antioxidant level was low (p < 0.01). Although a positive correlation was found between the prolidase and total antioxidant levels and the total oxidant level, no correlation was found between prolidase and the oxidative stress index.

CONCLUSIONS

It has been determined that the activity of the prolidase enzyme increases due to the increased collage turnover in psoriasis patients. Increased serum oxidant levels and oxidative stress indices values may play a role in the pathogenesis of psoriasis.

Serum prolidase activity and oxidant-antioxidant status in children with chronic hepatitis B virus infection

BACKGROUND

Chronic hepatitis B (CHB) is a global health problem that can result in serious complications associated with collagen degradation. Prolidase is a specific imidodipeptidase that plays an important role in the breakdown of collagen. The aim of this study was to investigate prolidase activity and oxidant-antioxidant status in children with CHB.

METHODS

This prospective case control study includes 38 patients with CHB, 31 patients with inactive hepatitis B (IHB), and 29 healthy matched control subjects. Serum prolidase enzyme activity (SPEA), total antioxidant capacity (TAC), total oxidative activity (TOA), and malondialdehyde (MDA) level were measured and oxidative stress index (OSI) was calculated for each group.

RESULTS

Patients with CHB had significantly higher SPEA levels (207.82 ± 186.80 IU/L) than did the controls (58.6 ± 38.1 IU/L) and IHB patients (67.1 ± 39.9) (p < 0.001). CHB patients also had significantly higher TOA (45.0 ± 19.9 vs. 29.4 ± 11.7 (μmolH2O2 Eq./L), p = 0.005), OSI (33.1 ± 21.4 vs. 17.5 ± 10.2, p = 0.002) and MDA (13.4 ± 4.0 vs. 7.8 ± 2.6 μm/L, p < 0.001) values compared with the controls. TOA (32.0 ± 10.0) and OSI (15.4 ± 11.0) values of IHB patients were significantly lower than those of CHB patients (p < 0.05). SPEA had significant correlations with HBV- DNA and ALT values (r =0.514 and r =0.454, p < 0.001).

CONCLUSION

Our results suggest that prolidase activity can be considered as a reliable marker for CHB and increased oxidative stress appears to be related to chronicity of the disease.

Nonalcoholic fatty liver disease: A comprehensive review of a growing epidemic

Nonalcoholic fatty liver disease (NAFLD) is quickly becoming one of the most prominent causes of liver disease worldwide. The increasing incidence of NAFLD is tied to the obesity epidemic and the subsequent metabolic derangements brought along with it. Current efforts to elucidate the mechanism and causes of the disease have answered some questions, but much remains unknown about NAFLD. The aim of this article is to discuss the current knowledge regarding the pathogenesis of the disease, as well as the current and future diagnostic, preventative, and therapeutic options available to clinicians for the management of NAFLD.

Progress in the search for circulating biomarkers of nonalcoholic fatty liver disease

CONTEXT

The definitive standard for the diagnosis of nonalcoholic fatty liver disease (NAFLD) is clinico-pathological correlation, but frequently the only laboratory abnormality is an elevation of serum aminotransferases.

OBJECTIVE

This has resulted in the search for more specific laboratory biomarkers.

METHODS

The literature was searched for novel plasma/serum markers of NAFLD.

RESULTS

Studies reviewed here included histologically-confirmed patients presenting some stage of NAFLD and monitored one or more novel serum/plasma biomarkers.

CONCLUSION

The most promising application of some of these novel biomarkers for the detection and quantification of NAFLD and particularly NASH appears to be in the combination of several into diagnostic panels.

Biomarkers of liver fibrosis

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

Cordyceps cicadae induces G2/M cell cycle arrest in MHCC97H human hepatocellular carcinoma cells: a proteomic study

Background

Cordyceps cicadae is a medicinal fungus that is often used for treating cancer. However, the anticancer mechanisms of C. cicadae are largely unknown. This study aims to investigate the anticancer mechanisms of C. cicadae against hepatocellular carcinoma cells in vitro using a proteomic approach.

Methods

Human hepatocellular carcinoma MHCC97H cells were treated with a water extract of C. cicadae (0, 100, 250, 500, and 1000 μg/mL) for 48 h and harvested for cell viability assays. The significant differences in protein expression between control and C. cicadae-treated cells were analyzed by two-dimensional gel-based proteomics coupled with matrix-assisted laser desorption ionization-time of flight mass spectrometry. Flow cytometry analysis was employed to investigate the cell cycle and cell death. The anticancer molecular mechanism was analyzed by whole proteome mapping.

Results

The water extract of C. cicadae (0, 100, 250, 500, and 1000 μg/mL) inhibited the growth of MHCC97H cells in a dose-dependent manner via G2/M phase cell cycle arrest with no evidence of apoptosis. Among the identified proteins with upregulated expression were dynactin subunit 2, N-myc downstream-regulated gene 1, heat shock protein beta-1, alpha-enolase isoform 1, phosphatidylinositol transfer protein, and WD repeat-containing protein 1. Meanwhile, the proteins with downregulated expression were 14-3-3 gamma, BUB3, microtubule-associated protein RP/EB family member 1, thioredoxin-like protein, chloride intracellular channel protein 1, ectonucleoside triphosphate diphosphohydrolase 5, xaa-Pro dipeptidase, enoyl-CoA delta isomerase 1, protein-disulfide isomerase-related chaperone Erp29, hnRNP 2H9B, peroxiredoxin 1, WD-40 repeat protein, and serine/threonine kinase receptor-associated protein.

Conclusion

The water extract of C. cicadae reduced the growth of human hepatocellular carcinoma MHCC97H cells via G2/M cell cycle arrest.

Evaluation of the utility of serum prolidase as a marker for liver fibrosis

BACKGROUND

Liver dysfunction is common and often unrecognized. Liver biopsy is the gold standard in the assessment of liver fibrosis, but has disadvantages. We assessed the diagnostic accuracy of serum prolidase enzyme activity (SPA) in predicting the presence and degree of liver fibrosis, as compared with liver biopsy. Further, we evaluated the effect of hemolysis on measured SPA levels.

METHODS

We undertook a prospective case control study. Thirty eight outpatients without apparent liver illness and 20 patients with liver pathology scheduled to undergo liver biopsy had their SPA levels measured.

RESULTS

Patients undergoing liver biopsy had higher SPA levels (361 (268) IU/l [median (interquartile range)]) compared with controls (169 (160) (P < 0.001)). A SPA cutoff value of 200 IU/l yielded a sensitivity of 89%, specificity of 59%, an odds ratio of 11.5, negative predictive value of 92%, and a positive predictive value of 50%. Hemolysis causes an apparent increase in SPA levels.

CONCLUSION

Higher SPA levels in patients undergoing liver biopsies compared with controls may reflect the presence of liver fibrosis. SPA levels could not be used to stage the degree of fibrosis. SPA measurement may be useful in the diagnostic workup of suspected liver disease.

Does prolidase indicate worsening of hepatitis B infection?

BACKGROUND

Hepatitis B infection is a health problem that affects more than 400 million people all over the world. We aimed to evaluate the usability of prolidase enzyme that plays an important role in collagen synthesis. Prolidase levels increase in hepatic damage, which can be used as diagnostic parameters in the progressions to chronic hepatitis B (CHB) infection by evaluating it in different clinical forms of hepatitis B infection.

METHODS

A total of 69 patients who presented to our clinic with chronic hepatitis B (CHB) infection, 72 patients with inactive hepatitis B infection (IHB), and 45 healthy volunteers were included into this study. Alanine transaminase (ALT), Aspartate aminotransferase (AST) and prolidase levels of patients were measured. Hepatic biopsy was performed in patients with CHB infection. Prolidase levels were evaluated in three different groups, and its correlations with fibrosis were investigated.

RESULTS

Prolidase was different between all groups (P < 0.001). Prolidase level was found to be higher in CHB and IHB compared to the control group. There was no correlation between this enzyme, fibrosis, and histological activity index.

CONCLUSION

In this present study, it is shown that prolidase levels increase in hepatitis B infection. It may be used as a biochemical marker in the chronic hepatitis B.

Systematic review with meta-analysis: non-invasive assessment of non-alcoholic fatty liver disease--the role of transient elastography and plasma cytokeratin-18 fragments

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) affects 15-40% of the general population. Some patients have non-alcoholic steatohepatitis (NASH) and progressive fibrosis, and would be candidates for monitoring and treatment.

AIM

To review current literature on the use of non-invasive tests to assess the severity of NAFLD.

METHODS

Systematic literature searching identified studies evaluating non-invasive tests of NASH and fibrosis using liver biopsy as the reference standard. Meta-analysis was performed for areas with adequate number of publications.

RESULTS

Serum tests and physical measurements like transient elastography (TE) have high negative predictive value (NPV) in excluding advanced fibrosis in NAFLD patients. The NAFLD fibrosis score comprises of six routine clinical parameters and has been endorsed by current American guidelines as a screening test to exclude low-risk individuals. The pooled sensitivities and specificities for TE to diagnose F ≥ 2, F ≥ 3 and F4 disease were 79% and 75%, 85% and 85%, and 92% and 92% respectively. Liver stiffness measurement often fails in obese patients, but the success rate can be improved with the use of the XL probe. A number of biomarkers have been developed for the diagnosis of NASH, but few were independently validated. Serum/plasma cytokeratin-18 fragments have been most extensively evaluated and have a pooled sensitivity of 66% and specificity of 82% in diagnosing NASH.

CONCLUSIONS

Current non-invasive tests are accurate in excluding advanced fibrosis in NAFLD patients, and may be used for initial assessment. Further development and evaluation of NASH biomarkers are needed.

Non-invasive diagnosis of non-alcoholic fatty liver disease. A critical appraisal

Non-alcoholic fatty liver disease (NAFLD) affects one in every three subjects in the occidental world. The vast majority will not progress, but a relevant minority will develop liver cirrhosis and its complications. The classical gold standard for diagnosing and staging NAFLD and assessing fibrosis is liver biopsy (LB). However, it has important sample error issues and subjectivity in the interpretation, apart from a small but real risk of complications. The decision to perform an LB is even harder in a condition so prevalent such as NAFLD, in which the probability of finding severe liver injury is low. In an attempt to overcome LB and to subcategorize patients with NAFLD in different prognoses allowing better management decisions, several non-invasive methods have been studied in the last decade. The literature is vast and confusing. This review will summarize which methods have been tested and how they perform, which tests are adequate for clinical practice and how they can change the management of these patients.

Prolidase could act as a diagnosis and treatment mediator in lung fibrosis

Idiopathic pulmonary fibrosis (IPF) is a chronic lung disease with unknown etiology and pathogenesis. With high mortality risks, most of the IPF cases emerged after a damage of alveolar epithelium, where this situation stimulates the over expression of matrix components. Inflammatory process observed as a reaction to emerged damage. Prolidase as an iminodipeptidase significantly increased during the development of fibrosis. The aim of this study is to measure prolidase activity as a marker of treatment and diagnosis in an experimental lung fibrosis animal model. Thirty male Wistar rats randomly divided into three experimental groups, with ten rats in each group. Group 1, control group; group 2, bleomycin (BLM)-induced lung fibrosis group, and group 3, BLM-induced lung fibrosis treated with palosuran (urotensin-II receptor antagonist). For histopathology, the middle lobes of right lungs were embedded in paraffin, followed by fixation in 10 % buffered formalin, and evaluation of IPF was performed using the Ashcroft scoring method. Prolidase activity was determined by a photometric method based on the measurement of proline levels produced by prolidase. The fibrosis scores and the prolidase activity were significantly enhanced by BLM stimulation. The BLM + palosuran treatment decreased prolidase activity in group 3. There was a positive correlation between prolidase activity and fibrosis scores. Palosuran seems to be effective in the treatment of lung fibrosis, and prolidase activity can be used for the diagnosis and/or for management of the treatment. However, further clinical and experimental studies with animals and/or patients are needed to verify these conclusions.

Prolidase and oxidative stress in chronic hepatitis C

BACKGROUND

Hepatitis C infection represents a common healthcare issue worldwide. The present trial was designed to investigate the role of prolidase, an enzyme that is significantly involved in the biosynthesis of collagen, and of the oxidative stress that is considered to be involved in the pathogenesis of various diseases, in the chronic hepatitis C infection. The trial was performed to assess the serum prolidase enzyme level and the oxidative-antioxidative status and to determine the relation between the serum prolidase activity and the oxidative stress parameters.

METHODS

A total of 95 individuals, including 55 patients with chronic hepatitis C infection (CHC) and 40 healthy adults, were enrolled in the trial. The values for prolidase, the total antioxidant status (TAS), the total oxidative stress (TOS), the oxidative stress index (OSI), sulfhydryl (SH), lipid peroxidation LOOH, catalase (CAT), and ceruloplasmin were measured and compared between the patient groups.

RESULTS

The prolidase, TOS, LOOH, CAT, and the OSI values were higher in the chronic hepatitis C group compared to the control group (P < 0.001). The TAS, SH, and ceruloplasmin levels were lower in the CHC group relative to the control group (P < 0.001).

CONCLUSION

We suppose that the values of prolidase and the oxidative stress are increased while the antioxidant levels are decreased in CHC. As a result, prolidase and the oxidative stress seem to be related with the progression of the disease.

Urinary metabolite variation is associated with pathological progression of the post-hepatitis B cirrhosis patients

Cirrhosis is a common and terminal outcome of many chronic liver conditions. A urinary metabonomic study using gas chromatography-mass spectrometry (GC-MS) and ultra performance liquid chromatography time-of-flight mass spectrometry (UPLC-TOFMS) was carried out to elucidate the pathophysiological basis of posthepatitis B cirrhosis in 63 posthepatitis B cirrhosis patients and 31 health controls. Urinary metabolic profile and corresponding differential metabolites associated with Child-Pugh (CP) grading of liver function were characterized, in addition to the blood routine, liver, and renal function tests. Multivariate statistical tools including principal component analysis (PCA) and orthogonal partial least-squares-discriminant analysis (OPLS-DA) were employed in the metabolite analysis along with a univariate statistical method, Wilcoxon-Mann-Whitney test. The alterations of differential metabolites contributing to the intergroup variation between healthy controls and cirrhotic patients, and among cirrhosis of CP grade A, B and C were also investigated. Six metabolites, α-hydroxyhippurate, tyrosine-betaxanthin, 3-hydroxyisovalerate, canavaninosuccinate, estrone, and glycoursodeoxycholate, were significantly altered among cirrhotic patients with CP A, B, and C, reflecting abnormal metabolism of amino acid, bile acids, hormones, and intestinal microbial metabolism. The results show that dynamic alteration of urinary metabolome, characterized by the changes of a panel of the differential metabolite markers, is indicative of an exacerbated liver function, highlighting their diagnostic and prognostic potential for the liver cirrhosis development.

Non-invasive Diagnosis of Fibrosis in Non-alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease in developed as well as in developing countries. Its prevalence continues to rise currently affecting approximately 20-30% of adults and 10% of children in the United States. Non-alcoholic fatty liver disease represents a wide spectrum of conditions ranging from fatty liver, which in general follows a benign non-progressive clinical course, to non-alcoholic steatohepatitis (NASH), a more serious form of NAFLD that may progress to cirrhosis and end-stage liver disease. Liver biopsy remains the gold standard for evaluating the degree of hepatic necroinflammation and fibrosis; however, several non-invasive investigations, such as serum biomarkers, have been developed to establish the diagnosis and also to evaluate treatment response. There has been a substantial development of non-invasive risk scores, biomarker panels, and radiological modalities to identify at risk patients with NAFLD without recourse to liver biopsy on a routine basis. Examples include combination of serum markers like NAFLD fibrosis score (NFS), BARD score, fibrometer, FIB4, and non-invasive tools like fibroscan which assess fibrosis in patients with NAFLD. Other markers of fibrosis that have been evaluated include high-sensitivity C-reactive protein, plasma pentraxin 3, interleukin-6, and cytokeratin-18. This review focuses on the methods currently available in daily clinical practice in hepatology and touches briefly on the potential future markers under investigation.

Non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) refers to the accumulation of hepatic steatosis not due to excess alcohol consumption. The prevalence of NAFLD is up to 30% in developed countries and nearly 10% in developing nations, making NAFLD the most common liver condition in the world. The pathogenesis of NAFLD is related to insulin resistance and, thus, it is frequently found in individuals who have central obesity or diabetes. Insulin resistance and excess adiposity are associated with increased lipid influx into the liver and increased de novo hepatic lipogenesis, promoting hepatic triglyceride accumulation. Defects in lipid utilization via mitochondrial oxidation and lipid export may also contribute to hepatic lipid build-up. Adipocytokine alterations, lipotoxicity from saturated fatty acids and fructose have been all been implicated in causing hepatocyte injury in NAFLD through pathways involving oxidative and endoplasmic reticulum stress. Clinically, NAFLD is commonly asymptomatic and frequently detected incidentally by blood liver function tests or imaging performed for other reasons. Subjects with NAFLD have a higher mortality rate than the general population and are at increased risk of developing cardiovascular disease and diabetes in the future. Histologically, NAFLD occurs as a spectrum from mild hepatic steatosis only, to non-alcoholic steatohepatitis (NASH) characterized by hepatocellular injury and inflammation, to cirrhosis. A diagnosis of NASH with associated fibrosis heralds a more significant prognosis as it is more likely to progressive to cirrhosis with complications of hepatic failure and hepatocellular carcinoma. Currently, the diagnosis of NASH requires a liver biopsy, however, serum based markers of hepatocyte apoptosis such as cytokeratin-18 fragments offer promise as accurate non-invasive diagnostic tests. Treatment of NAFLD revolves around addressing concomitant metabolic risk factors and improving insulin resistance through weight loss measures and exercise. Insulin sensitizing agents such as pioglitazone and anti-oxidant agents such as vitamin E show some promise in improving liver histology in patients with NASH, however, the long-term benefit of these medications has not been demonstrated.

Diagnosis and evaluation of nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is the most common cause of elevated liver function tests results, after the commonly investigated causes have been excluded, and frequently coexists with type 2 diabetes mellitus (T2DM) because the conditions have common risk factors. As both T2DM and NAFLD are related to adverse outcomes of the other, diagnosis and valuation of fatty liver is an important part of the management of diabetes. Although noninvasive methods, such as biomarkers, panel markers, and imaging, may support a diagnostic evaluation of NAFLD patients, accurate histopathological findings cannot be achieved without a liver biopsy. As it is important to know whether steatohepatitis and liver fibrosis are present for the management of NAFLD, liver biopsy remains the gold standard for NAFLD diagnosis and evaluation. Therefore, new investigations of the pathogenesis of NAFLD are necessary to develop useful biomarkers that could provide a reliable noninvasive alternative to liver biopsy.

Improved prolidase activity assay allowed enzyme kinetic characterization and faster prolidase deficiency diagnosis

BACKGROUND

Prolidase is a metallo-exopeptidase hydrolyzing X-Pro and X-Hyp dipeptides. Its absence or reduced level is typical in prolidase deficiency (PD) patients, and altered prolidase activity was reported in various diseases. Therefore, standardized and accurate measurement of prolidase activity is essential for PD diagnosis, as well as to elucidate the pathophysiology of other disorders.

METHODS

Human recombinant prolidase was used to optimize a spectrophotometric enzyme activity assay. Kinetic parameters and Mn(2+) affinity were evaluated. The method was validated on blood and fibroblasts from PD patients.

RESULTS

An activation step consisting in prolidase incubation with 1 mmol/l MnCl(2) and 0.75 mmol/l reduced glutathione at 50°C for 20 min was necessary to obtain the maximum activity and to accurately determine, for the recombinant enzyme, V(max) (489 U/mg), K(m) (5.4 mM) and Mn(2+) affinity (54 mM(-1)). The method applied to PD diagnosis revealed an intra-assay CV=8% for blood and 9% for fibroblasts lysates. The inter-assay CV was 21% for blood and 20% for cell lysates.

CONCLUSION

We optimized a faster spectrophotometric method to measure the activity when the enzyme is fully activated, this is crucial to allow a reliable evaluation of prolidase activity from different sources.

Systematic review: the diagnosis and staging of non-alcoholic fatty liver disease and non-alcoholic steatohepatitis

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) has become the most prevalent cause of liver disease in Western countries. The development of non-alcoholic steatohepatitis (NASH) and fibrosis identifies an at-risk group with increased risk of cardiovascular and liver-related deaths. The identification and management of this at-risk group remains a clinical challenge.

AIM

To perform a systematic review of the established and emerging strategies for the diagnosis and staging of NAFLD.

METHODS

Relevant research and review articles were identified by searching PubMed, MEDLINE and EMBASE.

RESULTS

There has been a substantial development of non-invasive risk scores, biomarker panels and radiological modalities to identify at-risk patients with NAFLD without recourse to liver biopsy on a routine basis. These modalities and algorithms have improved significantly in their diagnosis and staging of fibrosis and NASH in patients with NAFLD, and will likely impact on the number of patients undergoing liver biopsy.

CONCLUSIONS

Staging for NAFLD can now be performed by a combination of radiological and laboratory techniques, greatly reducing the requirement for invasive liver biopsy.

Non-invasive diagnosis of nonalcoholic fatty liver and nonalcoholic steatohepatitis

Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease in the USA and many other parts of the world. Its prevalence continues to rise; currently affecting about one in four adults and 10% of children in the USA. NAFLD represents a wide spectrum of conditions ranging from fatty liver, which in general follows a benign, no-progressive clinical course, to nonalcoholic steatohepatitis (NASH), a more serious form of NAFLD that may progress to cirrhosis and end-stage liver disease. Currently, the diagnosis of NASH requires an invasive liver biopsy with drawbacks of sampling and interpretation error. Clinical risk factors for NASH include diabetes and the metabolic syndrome; however, these are not sufficiently predictive of the condition by themselves. Routine liver enzyme levels are not reliable; however, novel plasma hepatocyte cell death markers either alone or in combination with clinical risk factors are potential non-invasive diagnostic tools for the future. This review provides a concise overview of the role non-invasive diagnostic tools for the differentiation of fatty liver from NASH as well as for the determination of presence and extent of fibrosis.

Analysis of positional candidate genes in the AAA1 susceptibility locus for abdominal aortic aneurysms on chromosome 19

BACKGROUND

Abdominal aortic aneurysm (AAA) is a complex disorder with multiple genetic risk factors. Using affected relative pair linkage analysis, we previously identified an AAA susceptibility locus on chromosome 19q13. This locus has been designated as the AAA1 susceptibility locus in the Online Mendelian Inheritance in Man (OMIM) database.

METHODS

Nine candidate genes were selected from the AAA1 locus based on their function, as well as mRNA expression levels in the aorta. A sample of 394 cases and 419 controls was genotyped for 41 SNPs located in or around the selected nine candidate genes using the Illumina GoldenGate platform. Single marker and haplotype analyses were performed. Three genes (CEBPG, PEPD and CD22) were selected for DNA sequencing based on the association study results, and exonic regions were analyzed. Immunohistochemical staining of aortic tissue sections from AAA and control individuals was carried out for the CD22 and PEPD proteins with specific antibodies.

RESULTS

Several SNPs were nominally associated with AAA (p < 0.05). The SNPs with most significant p-values were located near the CCAAT enhancer binding protein (CEBPG), peptidase D (PEPD), and CD22. Haplotype analysis found a nominally associated 5-SNP haplotype in the CEBPG/PEPD locus, as well as a nominally associated 2-SNP haplotype in the CD22 locus. DNA sequencing of the coding regions revealed no variation in CEBPG. Seven sequence variants were identified in PEPD, including three not present in the NCBI SNP (dbSNP) database. Sequencing of all 14 exons of CD22 identified 20 sequence variants, five of which were in the coding region and six were in the 3'-untranslated region. Five variants were not present in dbSNP. Immunohistochemical staining for CD22 revealed protein expression in lymphocytes present in the aneurysmal aortic wall only and no detectable expression in control aorta. PEPD protein was expressed in fibroblasts and myofibroblasts in the media-adventitia border in both aneurysmal and non-aneurysmal tissue samples.

CONCLUSIONS

Association testing of the functional positional candidate genes on the AAA1 locus on chromosome 19q13 demonstrated nominal association in three genes. PEPD and CD22 were considered the most promising candidate genes for altering AAA risk, based on gene function, association evidence, gene expression, and protein expression.

Serum prolidase enzyme activity and its relation to histopathological findings in patients with non-alcoholic steatohepatitis

The aim of this study was to investigate serum prolidase enzyme activity and to find out its association with liver biopsy specimens' histopathological findings in patients with nonalcoholic steatohepatitis (NASH), which may progress to liver fibrosis and cirrhosis. Thirty-six patients with biopsy-proven NASH and 29 healthy controls were enrolled. Serum prolidase enzyme activity was measured spectrophotometrically. Serum prolidase enzyme activity was significantly higher in patients with NASH than controls (P=0.016). A significant correlation was observed between serum prolidase enzyme activity and fibrosis score in patients with NASH (r=0.661, P<0.001). Serum prolidase activity seems to be correlated with the level of fibrosis. Monitoring serum prolidase activity may be a useful adjunctive tool in predicting liver fibrosis, especially in the absence of advanced fibrosis and other conditions, which may affect the interpretation of prolidase activity.

Strategies for the early detection of drug-induced hepatic steatosis in preclinical drug safety evaluation studies

Hepatic steatosis is characterized by the accumulation of lipid droplets in the liver. Although relatively benign, simple steatosis can eventually lead to the development of steatohepatitis, a more serious condition characterized by fibrosis, cirrhosis, and eventual liver failure if the underlying cause is not eliminated. According to the "two hit" theory of steatohepatitis, the initial hit involves fat accumulation in the liver, and a second hit leads to inflammation and subsequent tissue injury. Because some xenobiotics target liver fatty acid metabolism, especially mitochondrial β-oxidation, it is important to avoid potential drug candidates that can contribute to either the initiation of liver steatosis or progression to the more injurious steatohepatitis. The gold standard for the detection of these types of hepatic effects is histopathological examination of liver tissue. In animal studies, these examinations are slow, restricted to a single sampling time, and limited tissue sections. Recent literature suggests that rapid in vitro screening methods can be used early in the drug R&D process to identify compounds with steatotic potential. Further, progress in the identification of potential serum or plasma protein biomarkers for these liver changes may provide additional in vivo tools to the preclinical study toxicologist. This review summarizes recent developments for in vitro screening and in vivo biomarker detection for steatotic drug candidates.

Nonalcoholic steatohepatitis: risk factors and diagnosis

Nonalcoholic steatohepatitis (NASH) represents the progressive form of nonalcoholic fatty liver disease with greater potential to lead to liver-related morbidity and mortality. Diagnosing NASH mandates more intensive clinical management and consideration for clinical trials. Currently, the diagnosis of NASH requires a liver biopsy, which is invasive, with drawbacks in sampling and interpretation error. Clinical risk factors for NASH include diabetes and the metabolic syndrome; however, these are not sufficiently predictive of the condition by themselves. Routine liver aminotransaminase levels are not reliable; however, novel plasma hepatocyte apoptosis markers, either alone or in combination with clinical risk factors, are potential noninvasive diagnostic tools for the future.