Proteomic analysis reveals that apolipoprotein A1 levels are decreased in patients with Budd-Chiari syndrome

Circulating proteomic panels for diagnosis and risk stratification of acute-on-chronic liver failure in patients with viral hepatitis B

Chronic HBV infection (CHB) can lead to acute-on-chronic liver failure (HBV-ACLF) characterized by high mortality. This study aimed to reveal ACLF-related proteomic alterations, from which protein based diagnostic and prognostic scores for HBV-ACLF were developed. Methods: Ten healthy controls, 16 CHB, and 19 HBV-ACLF according to COSSH (Chinese group on the study of severe hepatitis B) criteria were enrolled to obtain the comprehensive proteomic portrait related to HBV-ACLF initiation and progression. Potential markers of HBV-ACLF were further selected based on organ specificity and functionality. An additional cohort included 77 healthy controls, 92 CHB and 71 HBV-ACLF was used to validate the proteomic signatures via targeted proteomic assays. Results: Significant losses of plasma proteins related to multiple functional clusters, including fatty acid metabolism/transport, immuno-response, complement and coagulation systems, were observed in ACLF patients. In the validation study, 28 proteins were confirmed able to separate ACLF, CHB patients. A diagnostic classifier P4 (APOC3, HRG, TF, KLKB1) was built to differentiate ACLF from CHB with high accuracy (auROC = 0.956). A prognostic model P8 (GC, HRG, HPR, SERPINA6, age, NEU, INR and total protein) was built to distinguish survivors from non-survivors in 28 and 90-days follow-up (auROC = 0.882, 0.871), and to stratify ACLF patients into risk subgroups showing significant difference in 28 and 90-days mortality (HR=7.77, 7.45, both P<0.0001). In addition, P8 score correlated with ACLF grades and numbers of extra-hepatic organ failures in ACLF patients, and was able to predict ACLF-associated coagulation and brain failure within 90 days (auROC = 0.815, 0.842). Conclusions: Proteomic signatures developed in this study reflected the deficiency of key hematological functions in HBV-ACLF patients, and show potential for HBV-ACLF diagnosis and risk prediction in complementary to current clinical based parameters.

Diagnosis and treatment guidelines for aberrant portal hemodynamics: The Aberrant Portal Hemodynamics Study Group supported by the Ministry of Health, Labor and Welfare of Japan

Idiopathic portal hypertension (IPH), causing aberrant portal hemodynamics, is a disease with an as yet unidentified cause and no established treatment protocol. The Japanese research group on IPH in Japan was set up in 1975 by the Ministry of Health, Labor and Welfare. Extrahepatic portal obstruction and Budd-Chiari syndrome (BCS) have since been added to the group's research subjects. The aims of the research group are to accurately evaluate the current status of the three diseases in Japan, elucidate their etiology and pathogenesis, and develop new treatments. Due to the long-term efforts of the Japanese research group, aberrant portal hemodynamics has been investigated in a variety of aspects, from epidemiological and pathological studies to molecular biology analyses. As a result, it has been shown that there are abnormal genes in the liver, specific for IPH. In addition, pathological findings of BCS were internationally compared and the difference in findings between Japan and Europe (or North America) has been clarified. Furthermore, it was found that complication rates of hepatocellular carcinoma in BCS were higher in Japan. Based on the research, "Diagnosis and treatment of aberrant portal hemodynamics (2001)", including diagnostic criteria for aberrant portal hemodynamics, was published in 2001. In 2013, it was revised to "Diagnosis and treatment guidelines for aberrant portal hemodynamics (2013)" after the incorporation of diagnosis and treatment in accordance with its current status.

Review article: the aetiology of primary Budd-Chiari syndrome - differences between the West and China

BACKGROUND

China may have the largest number of Budd-Chiari syndrome (BCS) cases in the world (at least 1914 original papers were published, and at least 20 191 BCS patients were reported). Considering the discrepancy in the clinical profiles and preferred treatment selection of primary BCS between the West and China, understanding its aetiology in these two different regions is very important.

AIM

To review the data from large cohort studies and meta-analyses to illustrate the epidemiology of risk factors for BCS in the West and China.

METHODS

Relevant papers were identified by major English- and Chinese-language databases, conference abstracts, and by manual search.

RESULTS

Risk factors reviewed include myeloproliferative neoplasms (MPNs) and their related gene mutations, anti-phospholipid syndrome, paroxysmal nocturnal haemoglobinuria (PNH), hyperhomocysteinaemia and 5,10-methylenetetrahydrofolate reductase (MTHFR) C677T mutation, factor V Leiden (FVL) and prothrombin G20210A mutations, inherited anti-thrombin, protein C and protein S deficiencies, pregnancy and puerperium, poverty, and family history.

CONCLUSIONS

We examined the differences in the aetiological distribution of BCS between the West and China. Several recommendations should be considered in Chinese BCS patients: (i) screening for hyperhomocysteinaemia and MTHFR mutation should be regularly performed; (ii) screening for MPNs, PNH, and anti-phospholipid syndrome should be selectively performed; (iii) inherited anti-thrombin, protein C, and protein S deficiencies should be actively explored; (iv) screening for FVL and prothrombin G20210A mutations may be unnecessary; and (v) the clinical significance of pregnancy and puerperium, poverty with bacterial infections and unsanitary environments, and family history as possible risk factors should never be neglected.

Proteomic analysis of venous thromboembolism: an update

Venous thromboembolism is a complex, multifactorial disorder, the pathogenesis of which typically involves a variety of inherited or acquired factors. The multifactorial etiology of this disease and the partial correlation between genotype and prothrombotic phenotype limit greatly the value of genetic analysis in assessing thrombotic risk. The integration of several new 'omics' techniques enables a multifaceted and holistic approach to the study of venous thrombotic processes and pave the way to the search and identification of novel blood biomarkers and/or effectors of thrombus formation that can also be the possible future target of new anticoagulant and thrombolytic therapies for more personalized medicine. This review provides a comprehensive overview of the latest candidate proteomic biomarkers of venous thrombosis and of the proteomics studies relevant to its pathophysiology, some of which seem to confirm the existence of a common physiopathological basis for venous thromboembolism and atherothrombosis.

Identification and characterization of α1 -antitrypsin in fibrin clots

BACKGROUND AND OBJECTIVES

Preliminary studies indicated that α1 -antitrypsin (A1AT) is the most abundant protein that is non-covalently bound to fibrin clots prepared from plasma. The aim of this study was to identify and characterize fibrin(ogen)-bound A1AT.

METHODS AND RESULTS

Plasma clots were prepared and extensively washed with saline. Clot-bound A1AT could only be extracted using denaturing agents such as urea, thiourea or SDS, pointing to an apparently strong association. Purified fibrinogen, but still containing A1AT as a contaminant, was gel filtered, which showed that the A1AT was bound to fibrinogen. A specific ELISA detected the presence of A1AT-fibrinogen complexes in both purified fibrinogen and pooled normal plasma. Finally, fibrin(ogen)-Sepharose chromatography indicated that A1AT purified from plasma contained a small fraction of fibrin(ogen)-binding A1AT. To study the inhibitory activity of fibrin(ogen)-bound A1AT, both fibrinogen containing A1AT and washed plasma clots were incubated with increasing amounts of elastase. SDS-PAGE and Western blotting showed under both conditions the generation of the A1AT-elastase complex as well as cleaved A1AT. The inhibitory activity of fibrin(ogen)-bound A1AT was also demonstrated by measuring elastase-induced lysis of fibrin clots.

CONCLUSION

Fibrin clots contain strongly bound A1AT, which is functionally active as a serine protease inhibitor (serpin). This A1AT might play a role in the local regulation of proteases involved in coagulation or fibrinolysis and represent a novel link between the inflammatory and hemostatic systems.

High-density cholesterol and apolipoprotein AI as modifiers of plasma fibrin clot properties in apparently healthy individuals

Low high-density lipoprotein cholesterol (HDL-C) increases cardiovascular risk, whereas its high levels protect against atherosclerosis via multiple beneficial effects. Dense and poorly lysable fibrin clot formation is observed in cardiovascular disease. We sought to investigate whether HDL-C and its major component apolipoprotein A (Apo A)-I affect fibrin clot properties. In 136 apparently healthy individuals (99 men, 37 women, aged 49-69 years) we determined plasma fibrin clot permeability (Ks coefficient) and lysis time (t50%) together with Apo A-I and lipoprotein (a) [Lp(a)] levels. The median HDL-C level was 1.33  mmol/l (range from 0.77 to 2.19  mmol/l). HDL-C was positively associated with Apo A-I (r = 0.62, P < 0.00001). HDL-C and Apo A-I were positively correlated with Ks (r = 0.52, P < 0.00001 and r = 0.44, P < 0.00001, respectively) and inversely with t50% (r = -0.44, P < 0.00001 and r = -0.35, P = 0.00003, respectively). No such associations were seen for other lipid variables. Ks and t50% were associated with Lp(a) (r = -0.42, P < 0.00001 and r = 0.42, P < 0.00001, respectively) and fibrinogen (r = -0.31, P = 0.00024 and r = 0.39, P < 0.00001, respectively). Individuals with HDL-C at least 1.4 mmol/l (n = 54) had 19% higher Ks (P = 0.00016) and 17% shorter t50% (P = 0.0012) than the remainder. After adjustment for age, fibrinogen, and Lp(a), HDL-C was the independent predictor of Ks (β = 0.7, P < 0.00001) and t50% (β = -0.62, P < 0.00001). This study shows that elevated HDL-C levels are associated with improved fibrin clot permeability and lysis, indicating a novel antithrombotic mechanism underlying the postulated beneficial effects of therapy targeted at HDL-C.

Evidence for an enhanced fibrinolytic capacity in cirrhosis as measured with two different global fibrinolysis tests

BACKGROUND AND OBJECTIVES

It has been known for a long time that cirrhosis is associated with hyperfibrinolysis, which might contribute to an increased risk and severity of bleeding. However, recent papers have questioned the presence of a hyperfibrinolytic state in cirrhotic patients and postulated a rebalanced system owing to concomitant changes in both pro- and anti-fibrinolytic factors. Therefore we re-investigated the fibrinolytic state of cirrhotic patients using two different overall tests including a recently developed test for global fibrinolytic capacity (GFC) using whole blood.

PATIENTS AND METHODS

Blood was collected from 30 healthy controls and 75 patients with cirrhosis of varying severity (34 Child-Pugh A, 28 Child-Pugh B and 13 Child-Pugh C). The plasma clot lysis time (CLT), which is inversely correlated with fibrinolysis, was determined as well as the GFC.

RESULTS

The mean CLT was 74.5 min in the controls and decreased significantly to 66.9 min in Child-Pugh class A patients, 59.3 min in class B patients and 61.0 min in class C patients, and hyperfibrinolysis existed in 40% of the patients. The median GFC was 1.7 μg mL(-1) in the controls and increased significantly to 4.0 μg mL(-1) in Child-Pugh class A patients, 11.1 μg mL(-1) in class B patients and 22.5 μg mL(-1) in class C patients, and hyperfibrinolysis existed in 43% of the patients. Taken together, 60% of the patients showed hyperfibrinolysis in at least one of the two global assays.

CONCLUSION

A rebalanced fibrinolytic system may occur, but hyperfibrinolysis is found in the majority of patients with cirrhosis.

Identification of fibrin clot-bound plasma proteins

Several proteins are known to bind to a fibrin network and to change clot properties or function. In this study we aimed to get an overview of fibrin clot-bound plasma proteins. A plasma clot was formed by adding thrombin, CaCl₂ and aprotinin to citrated platelet-poor plasma and unbound proteins were washed away with Tris-buffered saline. Non-covalently bound proteins were extracted, separated with 2D gel electrophoresis and visualized with Sypro Ruby. Excised protein spots were analyzed with mass spectrometry. The identity of the proteins was verified by checking the mass of the protein, and, if necessary, by Western blot analysis. Next to established fibrin-binding proteins we identified several novel fibrin clot-bound plasma proteins, including α₂-macroglobulin, carboxypeptidase N, α₁-antitrypsin, haptoglobin, serum amyloid P, and the apolipoproteins A-I, E, J, and A-IV. The latter six proteins are associated with high-density lipoprotein particles. In addition we showed that high-density lipoprotein associated proteins were also present in fibrinogen preparations purified from plasma. Most plasma proteins in a fibrin clot can be classified into three groups according to either blood coagulation, protease inhibition or high-density lipoprotein metabolism. The presence of high-density lipoprotein in clots might point to a role in hemostasis.

Biological variation in tPA-induced plasma clot lysis time

Hypofibrinolysis is a risk factor for venous and arterial thrombosis, and can be assessed by using a turbidimetric tPA-induced clot lysis time (CLT) assay. Biological variation in clot lysis time may affect the interpretation and usefulness of CLT as a risk factor for thrombosis. Sufficient information about assay variation and biological variation in CLT is not yet available. Thus, this study aimed to determine the analytical, within-subject and between-subject variation in CLT. We collected blood samples from 40 healthy individuals throughout a period of one year (average 11.8 visits) and determined the CLT of each plasma sample in duplicate. The mean (± SD) CLT was 83.8 (± 11.1) minutes. The coefficients of variation for total variation, analytical variation, within-subject variation and between-subject variation were 13.4%, 2.6%, 8.2% and 10.2%, respectively. One measurement can estimate the CLT that does not deviate more than 20% from its true value. The contribution of analytical variation to the within-subject variation was 5.0%, the index of individuality was 0.84 and the reference change value was 23.8%. The CLT was longer in the morning compared to the afternoon and was slightly longer in older individuals (> 40 years) compared to younger (≤40 years) individuals. There was no seasonal variation in CLT and no association with air pollution. CLT correlated weakly with fibrinogen, C-reactive protein, prothrombin time and thrombin generation. This study provides insight into the biological variation of CLT, which can be used in future studies testing CLT as a potential risk factor for thrombosis.