Von Willebrand factor could be an index of endothelial dysfunction in patients with cirrhosis: relationship to degree of liver failure and nitric oxide levels

Editorial: Prediction of decompensation/death in advanced chronic liver disease with vWF: Non-invasive vascular factors trump liver function

This article is linked to Dominik et al paper. To view this article, visit https://doi.org/10.1111/apt.17945

Von Willebrand factor for outcome prediction within different clinical stages of advanced chronic liver disease

BACKGROUND AND AIMS

The prognostic performance of von Willebrand factor (VWF) may vary across clinical stages of advanced chronic liver disease (ACLD). Therefore, we investigated the evolution of VWF and other biomarkers throughout the full ACLD spectrum and evaluated their stage-specific prognostic utility.

METHODS

We retrospectively included Viennese ACLD patients with available information on hepatic venous pressure gradient (HVPG), C-reactive protein (CRP)/VWF levels and outcomes. ACLD stages were defined according to D'Amico et al. We included an external validation cohort from Padua.

RESULTS

We observed gradual increases in VWF throughout ACLD stages. In contrast, HVPG levelled off in decompensated ACLD (dACLD), whereas MELD showed only minor changes in the early stages and CRP did not increase until stage 3. VWF was associated with hepatic decompensation/liver-related death in compensated ACLD (cACLD) in a fully adjusted model, while it was not independently predictive of ACLF/liver-related death in dACLD. After backward selection, HVPG/CRP/VWF remained the main predictors of hepatic decompensation/liver-related death in cACLD. Notably, the performance of the non-invasive CRP/VWF-based model was comparable to invasive HVPG-based models (C-index:0.765 ± 0.034 vs. 0.756 ± 0.040). The discriminative ability of the CRP/VWF-based model was confirmed in an external validation cohort using another VWF assay which yielded systematically lower values.

CONCLUSION

VWF is the only biomarker that gradually increases across all ACLD stages. It is of particular prognostic value in cACLD, where a CRP/VWF-based model is equivalent to an invasive HVPG-based model. Systematic differences in VWF underline the importance of interlaboratory surveys. Moreover, our findings reinforce the notion that, already in cACLD, inflammation is a key disease-driving mechanism.

Von Willebrand factor processing in patients with advanced chronic liver disease and its relation to portal hypertension and clinical outcome

BACKGROUND AND AIMS

Endothelial dysfunction and portal hypertension (PH) are reflected by increased von Willebrand factor antigen (VWF-Ag) levels in advanced chronic liver disease (ACLD). This study investigated VWF release and cleavage and their association with PH and clinical outcomes.

METHODS

Levels of VWF-Ag, VWF-N (VWF-propeptide), and VWF-A (VWF processed by the main VWF-cleaving protease ADAMTS13) were assessed in 229 patients with clinically stable ACLD (hepatic venous pressure gradient [HVPG] ≥ 6 mmHg; absence of bacterial infections or acute decompensation) undergoing HVPG-measurement. Liver-healthy individuals served as controls (n = 24).

RESULTS

VWF-Ag and VWF-N were similarly accurate for the identification of clinically significant PH (CSPH; HVPG ≥ 10 mmHg) in compensated ACLD (AUROC: VWF-Ag 0.748; VWF-N 0.728). ADAMTS13 activity was similar between patients with ACLD and controls and did not correlate with PH and disease severity, whereas VWF cleavage decreased in patients with CSPH (i.e., VWF-Ag/-A-ratio increased). In vitro VWF activity strongly reflected VWF-Ag levels (Spearman's r = 0.874, p < 0.001), but decreased (vs. controls) in patients with CSPH when normalized to VWF-Ag levels (VWF-activity/-Ag-ratio). VWF-Act/-Ag ratio correlated negatively with ADAMTS13 activity (r =- 0.256, p < 0.001). ADAMTS13 activity was independently predictive for (i) portal vein thrombosis (PVT) and (ii) hepatic decompensation or liver-related death.

CONCLUSIONS

VWF-Ag levels and its propeptide are similarly suitable surrogates of PH in patients with compensated ACLD. ADAMTS13-Act was not linked to disease and PH severity, however, when normalized to VWF-Ag, both VWF cleavage and VWF activity were decreased in patients with CSPH, as compared to liver-healthy individuals. Low ADAMTS13-Act was associated with presumably more procoagulant VWF and adverse outcomes.

CLINICAL TRIAL NUMBER

NCT03267615.

Viscoelastometry to Manage Bleeding in Liver Disease

A state of "re-balanced haemostasis" describes complex coagulation changes that arise in patients with liver disease. Changes include alterations in procoagulant and anticoagulant proteins, platelets and von Willebrand factor, as well as the fibrinolytic system. Various circumstances including infection, trauma, or surgery may disrupt this balance and predispose an individual to bleeding or thrombosis. The prothrombin time, international normalised ratio, and activated partial thromboplastin time are conventional coagulation screening tests that are routinely employed by clinicians to investigate unexplained bleeding, monitor anticoagulation, and inform preoperative assessments of bleeding risk. These standard coagulation tests assess quantitative defects in procoagulant clotting factors and are insensitive to levels of natural anticoagulants, which together with procoagulant factors, are often perturbed in liver disease. Therefore, the prolongation of clotting times measured by these tests often does not reflect the multifaceted alterations of haemostasis in these patients. Viscoelastic testing (VET) provides a more encompassing assessment of clotting function by recording real-time viscoelastic changes in whole blood and includes parameters that provide information on coagulation factor function, platelet contribution to clot formation, as well as fibrinolysis. To date, VET has been employed to predict and inform transfusion support in obstetric, trauma, and cardiac surgical fields, and its use in patients undergoing liver transplantation is well established. The ability of VET to accurately predict bleeding risk and precisely guide transfusion algorithms for patients with liver disease undergoing other invasive procedures or experiencing bleeding complications has been the topic of research over the last decade. This review is a critical summary of this data and provides a detailed snapshot of the position of VET as a clinical tool in patients with liver disease.

From the Discovery of ADAMTS13 to Current Understanding of Its Role in Health and Disease

ADAMTS13 (a disintegrin-like metalloprotease domain with thrombospondin type 1 motif, member 13) is a protease of crucial importance in the regulation of the size of von Willebrand factor multimers. Very low ADAMTS13 activity levels result in thrombotic thrombocytopenic purpura, a rare and life-threatening disease. The mechanisms involved can either be acquired (immune-mediated thrombotic thrombocytopenic purpura [iTTP]) or congenital (cTTP, Upshaw-Schulman syndrome) caused by the autosomal recessive inheritance of disease-causing variants (DCVs) located along the ADAMTS13 gene, which is located in chromosome 9q34. Apart from its role in TTP, and as a regulator of microthrombosis, ADAMTS13 has begun to be identified as a prognostic and/or diagnostic marker of other diseases, such as those related to inflammatory processes, liver damage, metastasis of malignancies, sepsis, and different disorders related to angiogenesis. Since its first description almost 100 years ago, the improvement of laboratory tests and the description of novel DCVs along the ADAMTS13 gene have contributed to a better and faster diagnosis of patients under critical conditions. The ability of ADAMTS13 to dissolve platelet aggregates in vitro and its antithrombotic properties makes recombinant human ADAMTS13 treatment a potential therapeutic approach targeting not only patients with cTTP but also other medical conditions.

Clinical significance of substantially elevated von Willebrand factor antigen levels in patients with advanced chronic liver disease

BACKGROUND

Von Willebrand factor antigen (VWF) is a non-invasive marker for clinically significant portal hypertension (HVPG≥10 mmHg) and confers HVPG-independent prognostic information. While quantification of increased VWF-levels is not relevant in the context of von Willebrand disease, highly elevated VWF may be of clinical significance in ACLD. Thus, we have modified our analytical approach to quantify very high VWF-levels (i.e.,>420%) and investigated their prognostic value.

METHODS

Patients undergoing HVPG-measurement at the Vienna Hepatic Hemodynamic Lab with evidence of ACLD and information on VWF were considered. Clinical stages (CS) were defined as follows: Probable compensated ACLD (cACLD): LSM≥10kPa&HVPG<6 mmHg; 0: cACLD&6-9 mmHg; 1: cACLD&HVPG≥10 mmHg; 2: bleeding; 3: non-bleeding decompensation; 4: ≥2 decompensations.

RESULTS

124 (16%) of 793 patients had VWF>420%. The proportion of VWF>420% increased with disease severity (probable cACLD-0: 5(4%) vs. 1: 22(10%) vs. 2-4: 97(23%),p ≤ 0.001) as well as across HVPG (<6mmHg: 1(2%) vs. 6-9: 6(6%) vs. 10-15: 17(9%) vs. ≥16: 100(22%),p ≤ 0.001) and MELD (<10: 17(6%) vs. 10-14: 27(10%) vs. ≥15: 79(32%),p ≤ 0.001) strata. In patients with VWF>420%, median VWF was 533 (IQR:466-611)% and VWF was unrelated to HVPG (Spearman's ρ=0.139,p = 0.123), but showed direct correlations of weak/moderate strength with MELD (ρ=0.336,p < 0.001) and CRP (ρ=0.286,p = 0.001). In the subgroup with VWF>420%, VWF was predictive of decompensation/liver-related mortality (VWF per 10%; hazard ratio (HR): 1.02(95% confidence interval (95%CI): 1.01-1.04),p = 0.008, even after adjusting for other factors (VWF per 10%; adjusted HR: 1.02(95%CI: 1.00-1.05),p = 0.031).

CONCLUSION

The proportion of patients with substantially elevated VWF values steadily increases with disease progression. While VWF is not reflective of HVPG in these patients, it is correlated with hepatic dysfunction and systemic inflammation. Importantly, quantification of high values provides prognostic information.

Plasma Endothelial and Oxidative Stress Biomarkers Associated with Late Mortality in Hospitalized COVID-19 Patients

Background: Coronavirus infectious disease 2019 (COVID-19) is a significant public health problem worldwide. COVID-19 increases the risk of non-pulmonary complications such as acute myocardial injury, renal failure, thromboembolic events, and multi-organic damage. Several studies have documented increased inflammation molecules, endothelial dysfunction biomarkers, and dysregulation of coagulation factors in COVID-19 patients. In addition, endothelium dysfunction is exacerbated by the oxidative stress (OxS) promoted by endocrine and cardiovascular molecules. Our objective was to evaluate whether endothelial and OxS biomarkers were associated with mortality in hospitalized COVID-19 patients. Methods: A prospective cohort study was performed. Patients ≥18 years old with confirmed COVID-19 that required hospitalization were included in a prospective cohort study. Endothelium and oxidative stress biomarkers were collected between 3 and 5 days after admission. Results: A total of 165 patients were evaluated; 56 patients succumbed. The median follow-up was 71 days [23–129]. Regarding endothelial dysfunction and OxS biomarkers, patients who did not survive had higher levels of nitrates (0.4564 [0.1817–0.6761] vs. 0.2817 [0.0517–0.5], p = 0.014), total nitrates (0.0507 [−0.0342–0.1809] vs. −0.0041 [−0.0887–0.0909], p = 0.016), sE-Selectin (1.095 [0.86–1.495] vs. 0.94 [0.71–1.19], p = 0.004), and malondialdehyde (MDA) (0.50 [0.26–0.72] vs. 0.36 [0.23–0.52], p = 0.010) compared to patients who survived. Endothelial and OxS biomarkers independently associated with mortality were sE-selectin (HR:2.54, CI95%; from 1.11 to 5.81, p = 0.027), nitrates (HR:4.92, CI95%; from 1.23 to 19.63, p = 0.024), and MDA (HR: 3.05, CI95%; from 1.14 to 8.15, p = 0.025). Conclusions: Endothelial dysfunction (sE-selectin and nitrates) and OxS (MDA) are independent indicators of a worse prognosis in COVID-19 patients requiring hospitalization.

Targeting von Willebrand factor in liver diseases: A novel therapeutic strategy?

Acute and chronic liver disease are associated with substantial alterations in the hemostatic system. Evidence from both experimental and clinical studies suggests that anticoagulants slow the progression of liver disease. Efficacy of those anticoagulant drugs is, in part, attributed to a reduction of microthrombi formation within the liver. Although anticoagulant drugs show promising results, bleeding risk associated with these drugs is an obvious drawback, particularly in patients with a complex coagulopathy driven by decreased liver function. Identifying therapies that reduce intrahepatic thrombosis with minimal bleeding risk would significantly advance the field. Among the hemostatic alterations observed in patients are substantially increased levels of the platelet-adhesive protein von Willebrand factor (VWF). In contrast, levels of A Disintegrin and Metalloproteinase with Thrombospondin motifs, the enzyme that regulates VWF activity, are significantly reduced in patients with liver disease. Highly elevated VWF levels are proposed to accelerate intrahepatic thrombus formation and thus be a driver of disease progression. Strong clinical evidence suggesting a link between liver disease and changes in VWF is now being matched by emerging mechanistic data showing a detrimental role for VWF in the progression of liver disease. This review focuses on clinical and experimental evidence supporting a connection between VWF function and the progression of acute and chronic liver diseases. Furthermore, with the recent anticipated approval of several novel therapies targeting VWF, we discuss potential strategies and benefits of targeting VWF as an innovative therapy for patients with liver disease.

The von Willebrand Factor Facilitates Model for End-Stage Liver Disease-Independent Risk Stratification on the Waiting List for Liver Transplantation

BACKGROUND AND AIMS

The Model for End-Stage Liver Disease (MELD) is used for clinical decision-making and organ allocation for orthotopic liver transplantation (OLT) and was previously upgraded through inclusion of serum sodium (Na) concentrations (MELD-Na). However, MELD-Na may underestimate complications arising from portal hypertension or infection. The von Willebrand factor (vWF) antigen (vWF-Ag) correlates with portal pressure and seems capable of predicting complications in patients with cirrhosis. Accordingly, this study aimed to evaluate vWF-Ag as an adjunct surrogate marker for risk stratification on the waiting list for OLT.

APPROACH AND RESULTS

Hence, WF-Ag at time of listing was assessed in patients listed for OLT. Clinical characteristics, MELD-Na, and mortality on the waiting list were recorded. Prediction of 3-month waiting-list survival was assessed by receiver operating characteristics and net reclassification improvement. Interestingly, patients dying within 3 months on the waiting list displayed elevated levels of vWF-Ag (P < 0.001). MELD-Na and vWF-Ag were comparable and independent in their predictive potential for 3-month mortality on the waiting list (area under the curve [AUC], vWF-Ag = 0.739; MELD-Na = 0.764). Importantly, a vWF-Ag cutoff at 413% identified patients at risk for death within 3 months of listing with a higher odds ratio (OR) than the previously published cutoff at a MELD-Na of 20 points (vWF-Ag, OR = 10.873, 95% confidence interval [CI], 3.160, 36.084; MELD-Na, OR = 7.594, 95% CI, 2.578, 22.372; P < 0.001, respectively). Ultimately, inclusion of vWF-Ag into the MELD-Na equation significantly improved prediction of 3-month waiting-list mortality (AUC, MELD-Na-vWF = 0.804).

CONCLUSIONS

A single measurement of vWF-Ag at listing for OLT predicts early mortality. Combining vWF-Ag levels with MELD-Na improves risk stratification and may help to prioritize organ allocation to decrease waiting-list mortality.

Heparin-like Effect Associated With Risk of Bleeding, Sepsis, and Death in Patients With Severe Alcohol-Associated Hepatitis

BACKGROUND & AIMS

Endogenous heparinoids or heparin-like effects (HLEs) can cause coagulation failure in patients with cirrhosis and sepsis. We performed a prospective study of the association between HLE and bleeding events, sepsis, and outcomes of patients with severe alcohol-associated hepatitis.

METHODS

Our final analysis comprised 78 patients with severe alcohol-associated hepatitis (44.3 ± 11.7 years; all male; discriminant function >32) who presented without sepsis at a single center in India from August 2015 through August 2016. Blood samples were collected at days 0, 3, and 7 after presentation and assessed by a global coagulation assay; by SONOCLOT (global and heparinase treated); and in assays for factor VIII, von Willebrand factor, protein C, and antithrombin. Patients were followed for sepsis, bleeding and outcome. The primary outcome was association of HLE with survival 28 days after presentation.

RESULTS

HLEs were observed in 32 patients (41%) at day 0, 27 patients (34.6%) at day 3, and 28 patients (35.9%) patients at day 7. Factors associated with mortality at day 0 were factor VIII activity >160% (hazard ratio [HR], 3.1; 95% CI, 1.4-9.5; P = .026), level of protein C <34% (HR, 0.7; 95% CI, 0.5-0.8; P = .037), antithrombin activity <28% (HR, 0.7; 95% CI, 0.3-1.1; P = .008) and international normalized ratio >2.6 (HR, 2.3; 95% CI, 1.8-9.7; P = .010). In multivariate analyses, only factor VIII activity (HR, 2.3; 95% CI, 1.6-7.8; P = .046), international normalized ratio (1.9; 95% CI, 1.2-4.3; P = .039), level of protein C (HR, 0.9; 95% CI, 0.7-1.1; P = .052) and model for end-stage liver disease score (HR, 3.2; 95% CI, 1.9-10.2; P = .042) were associated with mortality. Episodes of epistaxis, hemorrhoid bleeding, hemoperitoneum, and pulmonary hemorrhage occurred in 10.2%, 12.3%, 3.4%, and 4.5% of patients respectively. The presence of HLE at day 0 increased the risk of sepsis (HR, 2.5; 95% CI, 2.2-4.3; P = .002), bleeding (HR, 1.4; 95% CI, 1.2-5.3; P = .004) and death (HR, 1.2; 95% CI, 1.4-1.7; P = .044).

CONCLUSIONS

In a prospective study of patients with severe alcohol-associated hepatitis, we associated HLE with coagulation abnormalities, risk of sepsis, and mortality. Clinicaltrials.govNCT02307409.

Coagulation, Microenvironment and Liver Fibrosis

Fibrosis is the main consequence of any kind of chronic liver damage. Coagulation and thrombin generation are crucial in the physiological response to tissue injury; however, the inappropriate and uncontrolled activation of coagulation cascade may lead to fibrosis development due to the involvement of several cellular types and biochemical pathways in response to thrombin generation. In the liver, hepatic stellate cells and sinusoidal endothelial cells orchestrate fibrogenic response to chronic damage. Thrombin interacts with these cytotypes mainly through protease-activated receptors (PARs), which are expressed by endothelium, platelets and hepatic stellate cells. This review focuses on the impact of coagulation in liver fibrogenesis, describes receptors and pathways involved and explores the potential antifibrotic properties of drugs active in hemostasis in studies with cells, animal models of liver damage and humans.

Perioperative von Willebrand factor dynamics are associated with liver regeneration and predict outcome after liver resection

von Willebrand Factor (vWF) was found to mediate platelet influx during the early phase of liver regeneration in mice. Furthermore, increased vWF-antigen (vWF-Ag) levels were shown to be predictive for outcome of patients with chronic liver disease. Accordingly, we aimed to assess the relevance of perioperative vWF-Ag dynamics in terms of liver regeneration and clinical outcome in patients undergoing liver resection (LR). Accordingly, we observed that vWF-Ag and its activity-estimated by ristocetin cofactor measurement-increased immediately after induction of liver regeneration and was associated with platelet accumulation within the liver. However, a significant vWF-Ag burst was only observed in patients with unaffected postoperative liver regeneration. E-selectin, as an established marker for endothelial cell activation, was found to correlate with vWF-Ag in the liver vein after induction of liver regeneration (R = 0.535, P = 0.022). Preoperative vWF-Ag levels significantly predicted postoperative liver dysfunction (LD; N = 95; area under the curve, 0.725; P = 0.009). Furthermore, a cutoff of vWF-Ag ≥182% was defined to identify patients with a higher risk for postoperative LD or morbidity. This was confirmed within an independent mulitcenter validation cohort (N = 133). Ultimately, multivariable analysis revealed that vWF-Ag was an independent predictor of postoperative LD and morbidity.

CONCLUSION

Within this study, we were able to provide evidence that an initial vWF burst is required to allow for adequate platelet accumulation and concomitant liver regeneration post-LR and might be abolished as a consequence of intrahepatic endothelial cell dysfunction. We were further able to reveal and validate the potential of preoperative vWF-antigen levels to predict poor postoperative outcome in patients undergoing LR. Despite the pathophysiological relevance of our findings, vWF-Ag seems to be a valuable tool for preoperative risk assessment in patients undergoing LR. (Hepatology 2018;67:1516-1530).

Von Willebrand factor indicates bacterial translocation, inflammation, and procoagulant imbalance and predicts complications independently of portal hypertension severity

BACKGROUND

Elevated plasma von Willebrand factor antigen (vWF) has been shown to indicate the presence of clinically significant portal hypertension, and thus, predicts the development of clinical events in patients with cirrhosis.

AIM

To investigate the impact of bacterial translocation and inflammation on vWF, as well as the association between vWF and procoagulant imbalance. Moreover, we assessed whether vWF predicts complications of cirrhosis, independent of the severity of portal hypertension.

METHODS

Our study population comprised 225 patients with hepatic venous pressure gradient (HVPG) ≥ 10 mm Hg without active bacterial infections or hepatocellular carcinoma.

RESULTS

vWF correlated with markers of bacterial translocation (lipopolysaccharide-binding protein [LBP; ρ = 0.201; P = 0.021]), inflammation (interleukin 6 [IL-6; ρ = 0.426; P < 0.001] and C-reactive protein [CRP; ρ = 0.249; P < 0.001]), and procoagulant imbalance (factor VIII/protein C ratio; ρ = 0.507; P < 0.001). Importantly, the associations between vWF and these parameters were independent of HVPG. Moreover, vWF (per 10%) independently predicted variceal bleeding (hazard ratio [HR]: 1.08 [95% confidence interval (95% CI): 1.01-1.16]; P = 0.023), requirement of paracentesis (HR: 1.05 [95% CI: 1.01-1.1]; P = 0.023) and bacterial infections (HR: 1.04 [95% CI: 1-1.09]; P = 0.04) including spontaneous bacterial peritonitis (HR: 1.09 [95% CI: 0.999-1.18]; P = 0.053) on a trend-wise level. After backward elimination, vWF (HR: 1.05 [95% CI: 1.02-1.08]; P = 0.003) and CRP (per 10 mg/L; HR: 1.53 [95% CI: 1.14-2.05]; P = 0.005) remained in the final model for transplant-free mortality. Finally, the independent prognostic value of vWF/CRP groups for mortality was confirmed by competing risk analysis.

CONCLUSION

Our results demonstrate that vWF is not only a marker of portal hypertension but also independently linked to bacterial translocation, inflammation and procoagulant imbalance, which might explain its HVPG-independent association with most clinical events. Prognostic groups based on vWF/CRP efficiently discriminate between patients with a poor 5-year survival and patients with a favourable prognosis.

The Coagulation Profile of End-Stage Liver Disease and Considerations for Intraoperative Management

The coagulopathy of end-stage liver disease results from a complex derangement in both anticoagulant and procoagulant processes. With even minor insults, cirrhotic patients experience either inappropriate bleeding or clotting, or even both simultaneously. The various phases of liver transplantation along with fluid and blood product administration may contribute to additional disturbances in coagulation. Thus, anesthetic management of patients undergoing liver transplantation to improve hemostasis and avoid inappropriate thrombosis in the perioperative environment can be challenging. To add to this challenge, traditional laboratory tests of coagulation are difficult to interpret in patients with end-stage liver disease. Viscoelastic coagulation tests such as thromboelastography (Haemonetics Corporation, Braintree, MA) and rotational thromboelastometry (TEM International, Munich, Germany) have helped to reduce transfusion of allogeneic blood products, especially fresh frozen plasma, but have also lead to the increased use of fibrinogen-containing products. In general, advancements in surgical techniques and anesthetic management have led to significant reduction in blood transfusion requirements during liver transplantation. Targeted transfusion protocols and pharmacologic prevention of fibrinolysis may further aid in the management of the complex coagulopathy of end-stage liver disease.

von Willebrand factor antigen (vWF-Ag): A non-invasive predictor of treatment response and serious adverse events in HCV patients with interferon triple therapy

BACKGROUND

Treatment of chronic hepatitis C virus (HCV) infection was revolutionized within the last years. Interferon free antiviral regimens are not accessible without limitations. Combination of peginterferon/ribavirin with first generation direct acting antivirals is less effective and associated with serious adverse events.

AIM

We have shown that vWF-Ag is associated with portal hypertension and treatment response to PEG/RBV and we evaluated if vWF-Ag is a predictive marker for treatment response and safety in patients with triple therapy.

METHODS

222 HCV-GT 1 patients and DAA based triple therapy were included in this retrospective, multicenter study.

RESULTS

Median vWF-Ag levels were 167.0% [IQR: 124.0-210.0%]. Significantly higher levels were seen in patients without SVR; median 190% [IQR: 146.0-259.5%] versus SVR: 142.5% [IQR: 114.3-196.8%], p<0.001. Furthermore levels of vWF-Ag were identified as independent predictor of non SVR; (OR: 1.009; 95%CI: 1.016-1.3, p=0.005). In patients with cirrhosis elevated vWF-Ag levels were associated with increased incidence of SAEs (OR: 1.016; 95%CI: 1.004-1.028; p=0.007). Best cut off for prediction of SAEs was vWF-Ag>281.5% with a sensitivity of 78% and a specificity of 90%.

CONCLUSION

Baseline vWF-Ag levels predict outcome of DAA based treatment in HCV-1 patients and identify patients with a risk of SAEs. Therefore vWF-Ag may be an additional marker for selecting patients for interferon free therapeutic regimens.

von Willebrand factor antigen as a therapeutic target of portal hypertension in cirrhosis

Increased thrombotic potential within the liver sinusoids due to local endothelial production of von Willebrand factor antigen macromolecules could represent an additional therapeutic target of portal hypertension in patients with cirrhosis. In this case, anti-inflammatory and antithrombotic drugs could modulate portal pressure by preventing the formation of intrahepatic platelet-induced microthrombi.

Hemostatic balance in patients with liver cirrhosis: Report of a consensus conference

Patients with cirrhosis present with hemostatic alterations secondary to reduced availability of pro-coagulant and anti-coagulant factors. The net effect of these changes is a rebalanced hemostatic system. The Italian Association of the Study of the Liver (AISF) and the Italian Society of Internal Medicine (SIMI) promoted a consensus conference on the hemostatic balance in patients with cirrhosis. The consensus process started with the review of the literature by a scientific board of experts and ended with a formal consensus meeting in Rome in December 2014. The statements were graded according to quality of evidence and strength of recommendations, and approved by an independent jury. The statements presented here highlight strengths and weaknesses of current laboratory tests to assess bleeding and thrombotic risk in cirrhotic patients, the pathophysiology of hemostatic perturbations in this condition, and outline the optimal management of bleeding and thrombosis in patients with liver cirrhosis.

von Willebrand factor as a novel noninvasive predictor of portal hypertension and esophageal varices in hepatitis B patients with cirrhosis

OBJECTIVE

At present, there is no perfect noninvasive method to assess portal hypertension and esophageal varices. Early predicting esophageal varices can provide evidence for managing cirrhotic patients. We aimed to further investigate von Willebrand factor (vWF) as a noninvasive predictor of portal hypertension, especially of esophageal varices.

MATERIAL AND METHODS

A total of 60 hepatitis B patients with cirrhosis and 45 healthy subjects were enrolled in this study. Levels of six markers were examined. All patients underwent hepatic venous pressure gradient (HVPG) and esophagogastroduodenoscopy. We evaluated the performance of six factors for diagnosis of portal hypertension and esophageal varices. The vWF levels in liver tissues were observed by immunohistochemistry. Correlations between the level of vWF in liver tissues and HVPG and between levels of vWF in tissues and plasma were examined.

RESULTS

Cutoff values of plasma vWF (1510.5 mU/mL and 1701 mU/mL) showed high positive predictive value (PPV, 90.2% and 87.5%) in predicting clinically significant portal hypertension and severe portal hypertension. Cutoff values of vWF (1414 mU/ml and 1990 mU/mL, PPV 90.3% and 86.3%, respectively) were provided to detect the presence and degree of esophageal varices. Linear correlations were observed between levels of vWF in liver tissues and HVPG (r(2) = 0.552, p < 0.001) and between the level of vWF in liver tissues and in plasma (r(2) = 0.461, p < 0.001).

CONCLUSION

The vWF is a noninvasive predictor of portal hypertension and esophageal varices in hepatitis B patients with cirrhosis. Increased levels of vWF in liver tissues may induce the elevated plasma vWF levels, but molecular mechanism is needed for further study.

Relevance of ADAMTS13 to liver transplantation and surgery

A disintegrin-like and metalloproteinase with thrombospondin type-1 motifs 13 (ADAMTS13) specifically cleaves unusually-large von Willebrand factor (VWF) multimers under high shear stress, and down-regulates VWF function to form platelet thrombi. Deficiency of plasma ADAMTS13 activity induces a life-threatening systemic disease, termed thrombotic microangiopathy (TMA) including thrombotic thrombocytopenic purpura (TTP). Children with advanced biliary cirrhosis due to congenital biliary atresia sometimes showed pathological features of TMA, with a concomitant decrease of plasma ADAMTS13 activity. Disappearance of their clinical findings of TTP after successful liver transplantation suggested that the liver is a major organ producing plasma ADAMTS13. In situ hybridization analysis showed that ADAMTS13 was produced by hepatic stellate cells. Subsequently, it was found that ADADTS13 was not merely responsible to development of TMA and TTP, but also related to some kinds of liver dysfunction after liver transplantation. Ischemia-reperfusion injury and acute rejection in liver transplant recipients were often associated with marked decrease of ADAMTS13 and concomitant formation of unusually large VWF multimers without findings of TMA/TTP. The similar phenomenon was observed also in patients who underwent hepatectomy for liver tumors. Imbalance between ADAMTS13 and VWF in the hepatic sinusoid might cause liver damage due to microcirculatory disturbance. It can be called as “local TTP like mechanism” which plays a crucial role in liver dysfunction after liver transplantation and surgery.

Significant Association between Serum Levels of Von Willebrand Factor (vWF) Antigen with Stages of Cirrhosis

OBJECTIVE

Von Willebrand factor (vWF) is a mediator that increases endotoxemic medium like in cirrhosis. In this study we evaluated the association of serum VWF antigen (Ag) level with the stage of cirrhosis (according to Child-Pugh classification).

MATERIALS AND METHODS

We included 82 cirrhotic patients (Female/Male (F/M): 26/56) and 86 healthy subjects (F/M: 44/42) in the study. Ages of the both groups of patients were not different (P= 0.095). We excluded possible other reasons that may cause VWF level increase. Diagnosis of cirrhosis was made on the basis of biopsy in 7 patients and with clinical and laboratory parameters in 75 patients. VWF Ag level was determined by immunoturbidimetric test. The stage of cirrhosis was defined with Child-Pugh classification. Data were analysed by using Statistical Package for the Social Sciences (SPSS) 10.0 software program.

RESULTS

VWF Ag level was significantly higher in cirrhotic patients compared to control group (220±90 and 87±38, P<0.001, respectively). We observed significant increase of VWF Ag level with the increasing stages of cirrhosis according to Child-Pugh score (VWF Ag level for Child A-B-C 156.4±54/215±45/284.8±93, respectively; P values for Child A-B/A-C/B-C; <0.001/<0.001/0.006, respectively).

CONCLUSION

Serum VWF Ag level increases in cirrhotic patients and this is more pronounced with higher stages of cirrhosis.

Von Willebrand factor antigen for detection of hepatopulmonary syndrome in patients with cirrhosis

BACKGROUND & AIMS

Hepatopulmonary syndrome (HPS) occurs in 20-30% of patients with liver cirrhosis and is associated with a >2 fold increased mortality. Endothelial dysfunction seems to play a central role in its pathogenesis. von Willebrand factor antigen (vWF-Ag), an established marker of endothelial dysfunction, is significantly elevated in patients with liver cirrhosis, portal hypertension, and in experimental HPS. Aim of the present study was to evaluate the impact of vWF-Ag as a screening marker for presence of HPS in patients with stable cirrhosis.

METHODS

145 patients with stable liver cirrhosis were screened for presence of HPS in this prospective cohort type cross sectional diagnostic study. vWF-Ag and SaO2 levels were assessed at time of screening for HPS. Criteria of HPS were fulfilled in 31 (21%) patients.

RESULTS

vWF-Ag levels were significantly higher in patients with HPS compared to patients without HPS (p<0.001). Furthermore, vWF-Ag correlated significantly with gas exchange in HPS positive patients (p<0.05). vWF-Ag is an independent predictor of HPS after correction for sex, age, model for endstage-liver disease (MELD), and hepatic venous pressure gradient (HVPG) (OR per 1% increase of vWF-Ag: 1.02, 95% CI: 1.00-1.04, p<0.05). The best cut-off was 328% at a sensitivity of 100% and specificity of 53.5%; positive predictive value: 36.9%; negative predictive value: 100%.

CONCLUSIONS

HPS is associated with elevated vWF-Ag levels. vWF-Ag may be a useful screening tool for early detection of HPS. Further studies investigating vWF-Ag in HPS will be needed to confirm our findings.

Human serum albumin, systemic inflammation, and cirrhosis

Human serum albumin (HSA) is one of the most frequent treatments in patients with decompensated cirrhosis. Prevention of paracentesis-induced circulatory dysfunction, prevention of type-1 HRS associated with bacterial infections, and treatment of type-1 hepatorenal syndrome are the main indications. In these indications treatment with HSA is associated with improvement in survival. Albumin is a stable and very flexible molecule with a heart shape, 585 residues, and three domains of similar size, each one containing two sub-domains. Many of the physiological functions of HSA rely on its ability to bind an extremely wide range of endogenous and exogenous ligands, to increase their solubility in plasma, to transport them to specific tissues and organs, or to dispose of them when they are toxic. The chemical structure of albumin can be altered by some specific processes (oxidation, glycation) leading to rapid clearance and catabolism. An outstanding feature of HSA is its capacity to bind lipopolysaccharide and other bacterial products (lipoteichoic acid and peptidoglycan), reactive oxygen species, nitric oxide and other nitrogen reactive species, and prostaglandins. Binding to NO and prostaglandins are reversible, so they can be transferred to other molecules at different sites from their synthesis. Through these functions, HSA modulates the inflammatory reaction. Decompensated cirrhosis is a disease associated systemic inflammation, which plays an important role in the pathogenesis of organ or system dysfunction/failure. Although, the beneficial effects of HAS have been traditionally attributed to plasma volume expansion, they could also relate to its effects modulating systemic and organ inflammation.

An unbalance between von Willebrand factor and ADAMTS13 in acute liver failure: implications for hemostasis and clinical outcome

Emerging evidence supports the concept of a rebalanced hemostatic state in liver disease as a result of a commensurate decline in prohemostatic and antihemostatic drivers. In the present study, we assessed levels and functionality of the platelet-adhesive protein von Willebrand factor (VWF) and its cleaving protease ADAMTS13 in the plasma of patients with acute liver injury and acute liver failure (ALI/ALF). Furthermore, we explored possible associations between VWF, ADAMTS13, and disease outcome. We analyzed the plasma of 50 patients taken on the day of admission for ALI/ALF. The plasma of 40 healthy volunteers served as controls. VWF antigen levels were highly elevated in patients with ALI/ALF. In contrast, the collagen-binding activity and the ratio of the VWF ristocetin cofactor activity and VWF antigen was significantly decreased when compared with healthy controls. Also, the proportion of high molecular weight VWF multimers was reduced, despite severely decreased ADAMTS13 levels. In spite of these functional defects, platelet adhesion and aggregation were better supported by plasma of patients with ALI/ALF when compared with control plasma. Low ADAMTS13 activity, but not high VWF antigen, was associated with poor outcome in patients with ALI/ALF as evidenced by higher grades of encephalopathy, higher transplantation rates, and lower survival. VWF or ADAMTS13 levels were not associated with bleeding or thrombotic complications.

CONCLUSION

Highly elevated levels of VWF in plasma of patients with ALI/ALF support platelet adhesion, despite a relative loss of function of the molecule. Furthermore, low ADAMTS13 activity is associated with progressive liver failure in the patient cohort, which might be attributed to platelet-induced microthrombus formation in the diseased liver resulting from a substantially unbalanced VWF/ADAMTS13 ratio.

ADAMTS13 activity may predict the cumulative survival of patients with liver cirrhosis in comparison with the Child-Turcotte-Pugh score and the Model for End-Stage Liver Disease score

AIM

  Decreased plasma ADAMTS13 activity (ADAMTS13:AC) results in accumulation of unusually large von Willebrand factor multimers and platelet thrombi formation. Our aim was to evaluate whether ADAMTS13:AC is a prognostic marker in patients with liver cirrhosis.

METHODS

  Plasma ADAMTS13:AC and its related parameters were examined in 108 cirrhotic patients.

RESULTS

  ADAMTS13:AC decreased as the severity of liver disease increased (means: controls 100%, Child A-cirrhotics 79%, Child B-cirrhotics 63%, and Child C-cirrhotics 31%). ADAMTS13:AC markedly decreased in the cirrhotics with hepatorenal syndrome, refractory ascites and hepatic encephalopathy. The cumulative survival time was the shortest (median: 4.5 months) in the cirrhotics with severe to moderate ADAMTS13:AC deficiency (<3-25%), followed by those with mild ADAMTS13:AC deficiency (25-50%), and was the longest in those with normal activity (>50%). In contrast, based on the Child-Turcotte-Pugh (CTP) score, Child C-cirrhotics had the worst survival, but the survival probabilities did not differ between Child A and B cirrhotics. Based on the Model for End-Stage Liver Disease (MELD) score, the survival was the worst for the cirrhotics in the fourth quartile, but it was not different among cirrhotics in the first three quartiles. Cox proportional-hazards regression analysis showed that ADAMTS13:AC and serum albumin were independent factors affecting the survival.

CONCLUSIONS

  ADAMTS13:AC concomitantly decreases as the functional liver capacity decreases. This activity may be a useful prognostic marker that is equal or superior to the CTP score and the MELD score to predict not only the short-term prognosis but also the long-term survival of the cirrhotic patients.

Recipient and donor thrombophilia and the risk of portal venous thrombosis and hepatic artery thrombosis in liver recipients

Background

Vascular complications, such as HAT, are an important cause of graft loss and recipient mortality. We aimed to characterize post-transplant thrombotic events in a cohort of liver transplant recipients, and identify independent risk factors for these complications.

Methods

We conducted a thrombophilic study of 293 orthotopic liver transplants performed in the Digestive Surgery Department of the 12 de Octubre Hospital (Madrid, Spain) between January 2001 and December 2006.

Results

The most frequent post-transplant thrombotic events were HAT (9%) and PVT (1.7%). The one variable associated with post-transplant thrombotic event was a high fibrinogen level in the global cohort of liver transplantation. But toxicity as event post-OLT has been associated with post-transplant thrombotic event in the retrospective group and high fibrinogen level and low protein C levels were associated post-transplant thrombotic event in the prospective group. Liver disease relapse (HR 6.609, p < 0.001), high levels of FVIII (HR 1.008, p = 0.019)) and low levels of antithrombin (HR 0.946, p < 0.001) were associated with poor overall survival (OS).

In conclusion, high fibrinogen and decreased protein C levels were associated with allograft thrombosis. Further studies are required in order to assess the clinical relevance of these parameters in prospective studies and to study the effect of anticoagulation prophylaxis in this group of risk.

Determination of ADAMTS13 and Its Clinical Significance for ADAMTS13 Supplementation Therapy to Improve the Survival of Patients with Decompensated Liver Cirrhosis

The liver plays a central role in hemostasis by synthesizing clotting factors, coagulation inhibitors, and fibrinolytic proteins. Liver cirrhosis (LC), therefore, impacts on both primary and secondary hemostatic mechanisms. ADAMTS13 is a metalloproteinase, produced exclusively in hepatic stellate cells, and specifically cleaves unusually large von Willebrand factor multimers (UL-VWFM). Deficiency of ADAMTS13 results in accumulation of UL-VWFM, which induces platelet clumping or thrombi under high shear stress, followed by sinusoidal microcirculatory disturbances and subsequent progression of liver injuries, eventually leading to multiorgan failure. The marked imbalance between decreased ADAMTS13 activity (ADAMTS13 : AC) and increased production of UL-VWFM indicating a high-risk state of platelet microthrombi formation was closely related to functional liver capacity, hepatic encephalopathy, hepatorenal syndrome, and intractable ascites in advanced LC. Some end-stage LC patients with extremely low ADAMTS13 : AC and its IgG inhibitor may reflect conditions similar to thrombotic thrombocytopenic purpura (TTP) or may reflect "subclinical TTP." Hence, cirrhotic patients with severe to moderate deficiency of ADAMTS13 : AC may be candidates for FFP infusion as a source of ADAMTS13 or for recombinant ADAMTS13 supplementation. Such treatments may improve the survival of patients with decompensated LC.

A comprehensive analysis of the dynamic biological networks in HCV induced hepatocarcinogenesis

Hepatocellular carcinoma (HCC) is a primary malignancy of the liver, which is closely related to hepatitis C and cirrhosis. The molecular mechanisms underlying the hepatocarcinogenesis induced by HCV infection remain clarified from a standpoint of systems biology. By integrating data from protein-protein interactions, transcriptional regulation, and disease related microarray analysis, we carried out a dynamic biological network analysis on the progression of HCV induced hepatocarcinogenesis, and systematically explored the potentially disease-related mechanisms through a network view. The dysfunctional interactions among proteins and deregulatory relationships between transcription factors and their target genes could be causes for the occurrence and progression of this disease. The six pathologically defined disease stages in the development and progression of HCC after HCV infection were included in this study. We constructed disease-related biological networks for each disease stage, and identified progression-related sub-networks that potentially play roles in the developmental stage of the corresponding disease and participate in the later stage of cancer progression. In addition, we identified novel risk factors related to HCC based on the analysis of the progression-related sub-networks. The dynamic characteristics of the network reflect important features of the disease development and progression, which provide important information for us to further explore underlying mechanisms of the disease.

Pivotal role of ADAMTS13 function in liver diseases

The liver is a major source of clotting and fibrinolytic proteins, and plays a central role in thrombo-regulation. Patients with advanced liver diseases tend to bleed because of reduced plasma levels of several clotting factors and thrombocytopenia, but they do also exhibit thrombotic complications. ADAMTS13 is a metalloproteinase, produced exclusively in hepatic stellate cells, and specifically cleaves highly multimeric von Willebrand factor (VWF). VWF plays a pivotal role in hemostasis and thrombosis, and its function is dependent on its multimeric state. Deficiency of ADAMTS13 results in accumulation of unusually large VWF multimers (UL-VWFM) in plasma, in turn induces platelet clumping or thrombi under high shear stress, followed by microcirculatory disturbances. Considering that UL-VWFM, the substrate of ADAMTS13, is produced in transformed vascular endothelial cells at sites of liver injury, decreased ADAMTS13 activity may be involved in not only sinusoidal microcirculatory disturbances, but also subsequent progression of liver injuries, eventually leading to multiorgan failure. This concept can be applied to the development or aggravation of liver diseases, including liver cirrhosis, alcoholic hepatitis, veno-occlusive disease, and adverse events after liver transplantation. These results promise to bring further understanding of the pathophysiology of liver diseases, and offer new insight for development of therapeutic strategies.

Endothelial markers in schistosomiasis patients with or without portal hypertension

PURPOSE

To evaluate the serum levels of von Willebrand factor (vWF), vascular endothelial growth factor (VEGF), endothelin-1 (ET-1), and endothelin-3 (ET-3) in patients with the isolated, inactive form of Schistosomiasis mansoni. Patients were classified into two groups: 10 patients without (SM group) and 18 with (PH group) portal hypertension.

RESULTS

Serum albumin, VEGF, and vWF levels did not differ between the two groups (P > 0.05). The prothrombin time (INR), number of platelets, spleen size, splenic vein diameter, and endothelin levels differentiated the PH group, which showed decreased ET-1 (SM = 22.4 +/- 2.4 pg/ml and PH = 16.4 +/- 1.5 pg/ml; P = 0.034) and increased ET-3 (SM = 2.1 +/- 0.1 ng/ml and PH = 3.2 +/- 0.1 ng/ml; P = 0.000) levels.

CONCLUSIONS

In patients with schistosomiasis and portal hypertension (presinusoidal type), the levels of VEGF and ET-1 differ from those reported in patients with cirrhosis.

Superimposed coagulopathic conditions in cirrhosis: infection and endogenous heparinoids, renal failure, and endothelial dysfunction

In this article, the authors discuss three pathophysiologic mechanisms that influence the coagulation system in patients who have liver disease. First, bacterial infections may play an important role in the cause of variceal bleeding in patients who have liver cirrhosis, affecting coagulation through multiple pathways. One of the pathways through which this occurs is dependent on endogenous heparinoids, on which the authors focus in this article. Secondly, the authors discuss renal failure, a condition that is frequently encountered in patients who have liver cirrhosis. Finally, they review dysfunction of the endothelial system. The role of markers of endothelial function in cirrhotic patients, such as von Willebrand factor and endothelin-1, is discussed.

The platelet and platelet function testing in liver disease

Patients who have liver disease commonly present with alterations in platelet number and function. Recent data have questioned the contribution of these changes to bleeding complications in these patients. Modern tests of platelet function revealed compensatory mechanisms for the decreased platelet number and function, the most prominent compensatory mechanism being substantially elevated levels of the adhesive protein von Willebrand's factor. Consequently, standard diagnostic tests of platelet functions seem to be of little use to predict bleeding complication in patients who have liver disease. This article outlines the role of platelet abnormalities and possibilities for platelet function testing in patients who have liver disease.

Decreased Activity of Plasma ADAMTS13 May Contribute to the Development of Liver Disturbance and Multiorgan Failure in Patients with Alcoholic Hepatitis

BACKGROUND

The pathogenesis of alcoholic hepatitis (AH) remains unclear and the prognosis of severe alcoholic hepatitis (SAH) is very poor. Deficiency of von Willebrand factor (VWF)-cleaving protease (VWF-CP/ADAMTS13) results in an increase of the plasma unusually large VWF multimer and leads to platelet clumping, which causes microcirculatory disturbance and finally multiorgan failure. The aim of this study was to explore the potential role of ADAMTS13 on the development of liver disturbance and multiorgan failure in AH.

METHODS

The activity of plasma ADAMTS13 and its clinical correlation were determined in 14 patients with AH, 4 with SAH (Maddrey score, mean 62), and 10 with alcoholic liver cirrhosis (LC).

RESULTS

The activity of the plasma ADAMTS13 significantly decreased in patients with AH (mean 59%, p < 0.001), SAH (17%, p < 0.001) and LC (76%, p < 0.02) as compared with the healthy subjects (102%, n = 60). The activity was markedly lower in SAH than in AH (p < 0.02) and LC (p < 0.02). In three nonsurvivors with SAH who had multiorgan failure, it was extremely low (4.5%, 5.0%, and 16.0%, respectively), but in a survivor with SAH it remained mild decrease (44%). In AH, the protease activity increased at the recovery stage (42% --> 75%, p < 0.05). In the univariate analysis, the activity correlated with 10 clinical variables including functional liver capacity, inflammation signs, renal function, and platelet count in patients with AH and SAH. Among these, multivariate analysis showed that serum total bilirubin and C-reactive protein independently correlated with the protease activity.

CONCLUSION

The activity of plasma ADAMTS13 markedly decreased in SAH in addition to AH. The activity was closely related to hyperbilirubinemia and inflammation signs, and was extremely low in nonsurvivors with SAH and multiorgan failure. The marked decrease of plasma ADAMTS13 may, in part, contribute to not only the progression of liver disturbance in AH, but also the development of multiorgan failure in SAH through microcirculatory disturbance.

Increased von Willebrand factor over decreased ADAMTS13 activity may contribute to the development of liver disturbance and multiorgan failure in patients with alcoholic hepatitis

BACKGROUND

Severe alcoholic hepatitis (SAH) in addition to alcoholic hepatitis (AH) is a life-threatening complication of alcohol abuse, and its pathogenesis remains unclear. The deficiency of ADAMTS13 results in an increase of the plasma unusually large von Willebrand factor multimer (UL-VWFM) and finally causes microcirculatory disturbance and multiorgan failure. We investigated the relationship of ADAMTS13 and von Willebrand factor antigen (VWF:Ag) with the clinical features of AH and SAH.

METHODS

The plasma levels of ADAMTS13 activity, VWF:Ag, and UL-VWFM were determined in 24 patients with AH, 5 with SAH, and 10 with alcoholic liver cirrhosis (LC).

RESULTS

The ADAMTS13 activity was significantly lower in SAH (mean 24%), AH (62%), and LC (76%) than in the healthy subjects (102%, n=62). The VWF:Ag levels were higher in SAH (806%), AH (405%), and LC (514%) than in the healthy subjects (100%), resulting in a higher ratio of VWF:Ag to ADAMTS13 activity in SAH (102.2), AH (8.9), and LC (8.6) compared with the healthy subjects (1.0). In 3 nonsurvivors with SAH and multiorgan failure, the protease activity markedly decreased (from 4.5 to 16%), and VWF:Ag remarkably increased (from 560 to 1,202%), resulting in an extremely high ratio of VWF:Ag to the activity (from 35.0 to 240.4). At the recovery stage in the survivors with SAH and AH, the protease activity increased and the VWF:Ag decreased, whereas in a nonsurvivor with SAH, the activity remained extremely low and the VWF:Ag was still high. Unusually large von Willebrand factor multimer was detected in 80.0% of SAH and 55.6% of AH. Multivariate analysis showed that the serum albumin and platelet count independently correlated with VWF:Ag.

CONCLUSION

The enhanced production of UL-VWFM over deficient activity of ADAMTS13 may, in part, contribute to not only the progression of liver injury but also the development of multiorgan failure through microcirculatory disturbance in SAH in addition to AH. The imbalance between the plasma ADAMTS13 activity and VWF:Ag could be a useful prognostic marker in AH.

New insights into the coagulopathy of liver disease and liver transplantation

The liver is an essential player in the pathway of coagulation in both primary and secondary haemostasis. Only von Willebrand factor is not synthetised by the liver, thus liver failure is associated with impairment of coagulation. However, recently it has been shown that the delicate balance between pro and antithrombotic factors synthetised by the liver might be reset to a lower level in patients with chronic liver disease. Therefore, these patients might not be really anticoagulated in stable condition and bleeding may be caused only when additional factors, such as infections, supervene. Portal hypertension plays an important role in coagulopathy in liver disease, reducing the number of circulating platelets, but platelet function and secretion of thrombopoietin have been also shown to be impaired in patients with liver disease. Vitamin K deficiency may coexist, so that abnormal clotting factors are produced due to lack of gamma carboxylation. Moreover during liver failure, there is a reduced capacity to clear activated haemostatic proteins and protein inhibitor complexes from the circulation. Usually therapy for coagulation disorders in liver disease is needed only during bleeding or before invasive procedures. When end stage liver disease occurs, liver transplantation is the only treatment available, which can restore normal haemostasis, and correct genetic clotting defects, such as haemophilia or factor V Leiden mutation. During liver transplantation haemorrage may occur due to the pre-existing hypocoagulable state, the collateral circulation caused by portal hypertension and increased fibrinolysis which occurs during this surgery.

Proteome of endothelial cell-derived procoagulant microparticles

Microparticles (MP) are small membrane vesicles that are released from cells upon activation or during apoptosis. Cellular MP in body fluids constitute a heterogeneous population, differing in cellular origin, numbers, size, antigenic composition and functional properties. MP support coagulation by exposure of tissue factor (TF), the initiator of coagulation in vivo. Moreover, MP may transfer bioactive molecules to other cells, thereby stimulating them to produce cytokines, cell-adhesion molecules, growth factors and TF, and modulate endothelial functions. However, a comprehensive characterization of the antigenic composition of MP has been poorly defined. This study describes the protein composition of endothelial cell (EC)-derived MP (EMP) using a proteomic approach. MS analysis indicated the presence of newly described protein such as metabolic enzymes, proteins involved in adhesion and fusion processes, members of protein folding event, cytoskeleton associated proteins and nucleosome. In conclusion, circulating EMP behave as an actual storage pool, able to disseminate blood-borne TF activity and other bioactive effectors, as confirmed by our experiments showing an increased procoagulant activity of EC exposed to EMP.

A randomized unblinded pilot study comparing albumin versus hydroxyethyl starch in spontaneous bacterial peritonitis

The administration of albumin improves circulatory function, prevents hepatorenal syndrome, and reduces hospital mortality in patients with cirrhosis and spontaneous bacterial peritonitis. This randomized unblinded pilot study compared the effect of albumin (10 patients) and the synthetic plasma expander hydroxyethyl starch 200/0.5 (10 patients) on the systemic hemodynamics of patients with spontaneous bacterial peritonitis. Baseline measurements were performed within 12 hours after diagnosis of infection. Patients then received 2 doses of the volume expander (1.5 g/kg body weight after baseline measurements and 1 g/kg body weight on day 3). Measurements were repeated after infection resolution. Treatment with albumin was associated with a significant increase in arterial pressure and a suppression of plasma renin activity, indicating an improvement in circulatory function. This occurred in the setting of a significant expansion of central blood volume (increase in cardiopulmonary pressures and atrial natriuretic factor) and an increase in systolic volume and systemic vascular resistance. In contrast, no significant changes were observed in these parameters in patients treated with hydroxyethyl starch. Von Willebrand-related antigen plasma levels significantly decreased in patients treated with albumin but not in those treated with hydroxyethyl starch. Serum nitrates and nitrites increased in patients treated with hydroxyethyl starch but not in those treated with albumin. These data suggest an effect of albumin on endothelial function. In conclusion, albumin but not hydroxyethyl starch improves systemic hemodynamics in patients with spontaneous bacterial peritonitis. This effect is due not only to volume expansion but also to an action on the peripheral arterial circulation.

Cell-derived microparticles contain caspase 3 in vitro and in vivo

BACKGROUND

Microparticles (MP) from endothelial cells (endothelial microparticles; EMP) circulate in disease states, but the processes such as apoptosis or cell activation underlying their release are unclear.

OBJECTIVES

We investigated whether adherent (viable) or detached (apoptotic) endothelial cells are the possible source of EMP in vitro, i.e. under control and interleukin (IL)-1alpha activation conditions, and in vivo.

METHODS

Adherent and detached endothelial cells, and EMP, were isolated from human umbilical vein endothelial cell cultures (n = 6), treated without or with IL-1alpha (5 ng mL(-1); 24 h). Cell fractions were analyzed by flow cytometry for annexin V binding, propidium iodide (PI) and caspase 3 staining (n = 3). Caspase 3 in EMP was studied using Western blot (n = 6) and flow cytometry (n = 6). Plasma from healthy subjects and systemic lupus erythematosus patients (both n = 3) were analyzed for caspase 3-containing (E)MP.

RESULTS

Detached but not adherent cells double-stained for annexin V and PI, confirming the apoptotic conditions of the detached cells and the viable nature of the adherent cells. Caspase 3 was solely present in the detached cells and procaspase 3 in the adherent cells. Caspase 3 was present in EMP from both control and IL-1alpha-treated cultures. Counts of EMP and detached cells, but not adherent cells, highly correlated (r = 0.959, P < 0.0001). In vivo circulating MP from nucleated (endothelial cells, monocytes) and anucleated cells (platelets, erythrocytes) contained caspase 3.

CONCLUSIONS

EMP contain caspase 3 and may be mainly derived from detached (apoptotic) endothelial cells in vitro. The presence of caspase 3 in MP from anucleated cell types, however, suggests that its presence may not necessarily be related to apoptosis in vivo but may be associated with caspase 3 activation unrelated to apoptosis.

Localization of ADAMTS13 to the stellate cells of human liver

Although the chromosomal localization (9q34) of the gene encoding the human form of ADAMTS13 (a disintegrin-like and metalloproteinase with thrombospondin type-1 motifs 13) and its exclusive expression in the liver have been established, the cells that produce this enzyme are yet to be determined. We investigated the expression of ADAMTS13 mRNA and protein in fresh frozen specimens obtained during liver biopsies of 8 patients with liver diseases. In situ hybridizations to localize ADAMTS13 mRNA showed positive signals exclusively in perisinusoidal cells with irregularly elongated dendritic processes extending between hepatocytes. Furthermore, ADAMTS13 was detected immunohistochemically in perisinusoidal cells, whereas no staining was observed in hepatocytes. The positive cells varied in shape from unipolar to dendritic with irregularly elongated cytoplasmic processes, features common to hepatic stellate cells (HSCs). Double-labeling experiments revealed that the ADAMTS13-positive cells also expressed alpha-smooth muscle actin, confirming that these cells were activated HSCs. These results suggest that HSCs may be major cells producing ADAMTS13 in human liver.

Short- and long-term effects of therapy with interferon-alpha and pegylated interferon-alpha/ribavirin on platelet plug formation and von Willebrand factor release in patients with chronic hepatitis C

BACKGROUND

A pegylated interferon-alpha-induced decrease in platelet counts may become a limiting factor for continuation of therapy.

AIM

To evaluate the effect of pegylated interferon-alpha administration on platelet plug formation and von Willebrand factor antigen release in patients with chronic hepatitis C.

METHODS

Thirty patients with chronic hepatitis C (genotype 1; fibrosis 1-3: n = 16, cirrhosis: n = 14) received a single dose of 9 MU interferon-alpha2a, followed by weekly administration of 180 mug of pegylated interferon-alpha2a/ribavirin for 48 weeks. Platelet counts, platelet function (collagen-epinephrine-induced closure time) and von Willebrand factor antigen were measured.

RESULTS

Platelet counts and collagen-epinephrine-induced closure time decreased by 13% and 16%, respectively, 24 h after the first dose of interferon-alpha2a, and von Willebrand factor antigen levels increased by 31% (P < 0.01) compared with baseline. During a 48-week observation period, platelet counts decreased by a maximum of 33% (P < 0.001), von Willebrand factor antigen levels increased by 69% (P < 0.001) whereas collagen-epinephrine-induced closure time did not change. In noncirrhotic patients, the increase of von Willebrand factor antigen levels was maintained throughout therapy without a change in collagen-epinephrine-induced closure time. In contrast, in cirrhotics, von Willebrand factor antigen levels did not increase, while collagen-epinephrine-induced closure time was prolonged.

CONCLUSION

Single-dose interferon-alpha decreases platelet counts but improves platelet function, possibly by the release of von Willebrand factor antigen. Accordingly, long-term antiviral treatment had no effect on collagen-epinephrine-induced closure time, despite the decrease in platelet count in noncirrhotic patients. Such a compensation of decreased platelet counts by increased von Willebrand factor antigen level did not occur in cirrhotics.

Antigenic characterization of endothelial cell-derived microparticles and their detection ex vivo

BACKGROUND

Endothelial activation and dysfunction are associated with several diseases. However, hardly any specific markers are available. Microparticles (MP) from endothelial cells (EC; EMP) were reported in patient groups and healthy individuals. The antibodies used to detect EMP, however, were mainly directed against antigens without EC specificity.

OBJECTIVES

We evaluated the antigens on EC and EMP to establish proper markers for EMP detection.

METHODS

EMP were isolated from supernatants of resting and interleukin (IL)-1alpha activated human umbilical vein EC (HUVEC; n=3; 0-72 h), stained with annexin V and monoclonal antibodies, and analyzed by flow cytometry. Human platelet-MP (PMP), the main MP population in plasma, were prepared in vitro. EMP and PMP were studied in plasma from systemic lupus erythematosus (SLE) patients (n=11) and healthy individuals (n=10).

RESULTS

Platelet-endothelial cell adhesion molecule-1 (PECAM-1), alphanu and beta3 were constitutively exposed on HUVEC, but (almost) absent on EMP (<15% positive for alphanu and beta3), or only exposed on a subpopulation (PECAM-1; 30-60%). Activated HUVEC (>80%) and (subpopulations of) EMP exposed E-selectin and tissue factor. PMP strongly exposed PECAM-1, beta3, and glycoprotein (GP)Ib (CD42b), but not alphanu or E-selectin. GPIb and P-selectin (CD62P) were absent on EMP. Plasma samples contained 0.5% MP staining for E-selectin and/or alphanu. Plasma from one SLE patient contained E-selectin exposing MP (21%), but little alphanu-positive MP.

CONCLUSIONS

EC release EMP in vitro. The antigenic phenotype of EMP released from resting and IL-1alpha-stimulated EC differs among each other as well as from resting and stimulated EC, respectively. E-selectin exposed on IL-1alpha-stimulated EC is a valid marker for EMP detection ex vivo to establish endothelial cell activation.

Assessment of prognosis in alcoholic liver disease: can serum hyaluronate replace liver biopsy?

1. Only 15-20% of chronic alcohol misusers ever develop cirrhosis. 2. Currently it is not possible to predict clinically who will develop progressive fibrotic alcoholic liver disease. 3. Liver biopsy is currently the gold standard diagnostic test in alcoholic liver disease, but it has associated morbidity and mortality. 4. Serum hyaluronic acid is a simple non-invasive test that may be able to give an estimate of the severity of fibrosis in alcoholic liver disease. The full clinical assessment of alcoholic liver disease includes liver biopsy, since accurate clinical prediction of the severity of liver damage is extremely difficult in all except very advanced cases. Unfortunately, liver biopsy has an associated complication rate and is contraindicated in, or unacceptable to, some patients. A reliable non-invasive test of the severity of fibrotic disease would be clinically useful at initial clinical assessment in some patients with alcoholic liver disease. Such a test would be more useful in subsequent monitoring of disease progression, and in particular may diminish the need for follow-up liver biopsy. Serum hyaluronic acid has been put forward as such a non-invasive test. Based on current evidence, serum hyaluronic acid may well be a useful adjunctive test in the assessment of certain categories of alcoholic liver disease patients, but at present it is unlikely to displace liver biopsy as the investigation of choice in alcoholic liver disease.

Presentation of NO-metabolites (nitrate/nitrite) in blood serum and pleural effusions from cancer patients with pleurisy

To assess whether cancer-induced pleurisy is associated with an alteration of nitric oxide (NO)-synthase activity, the levels of nitrate/nitrite (NOx) were measured in blood serum (BS) and pleural effusion (PE) of 35 cancer patients (secondary pleural metastases and mesotheliomas), eight patients with benign lung diseases, and in BS of nine healthy donors. It was found that (1) BS of patients with secondary pleural metastases had an elevated level (P<0.015) of NOx (59.7+/-24.4 microM, n=28) in comparison with control level of BS for healthy donors (43.4+/-13.5 microM, n=9); (2) BS of mesotheliomas (32.1+/-12.2 microM, n=4) had significantly (P<0.05) lower level of NOx compared to BS of benign patients (61.2+/-28.8, n=6); (3) differences in mean levels of NOx in BS and same PE of examined patient groups did not reach statistical significance, excepting sub-group of patients with primary mammary carcinoma; (4) significant interindividual differences of NOx in all groups of patients were revealed; (5) fluids from about 11% of cancer patients contained extremely high levels of NOx over 100 microM; (6) a significant elevation of apparent NOx level in BS and PE of patients with secondary pleural metastases in comparison with those in BS of healthy donors was revealed when the native, i.e. protein-contained, samples were managed with Griess reagent. The results described here, point up the diverse role of NOx in cancer patients. Its role is far from being clear but it seems that NOx acts as a signaling mediator during the formation of pleural metastases and might be considered as a non-specific marker in the corresponding PE. Furthermore, NOx could be used to give rationale of proper application of anticancer drugs affecting diversely NO-synthase activity in cells. Besides, a casual effectiveness of NOx measurements in native samples from cancer patients using Griess reagent needs additional elaboration.

Clinical significance of plasma D-dimer and von Willebrand factor levels in patients with ulcer colitis

AIM: To investigate the levels of D-dimer (DD) and von Willebrand factor (vWF) and the relationship between DD and vWF in ulcerative colitis (UC) patients.

METHODS: A total of 29 plasma specimens were obtained from patients with ulcerative colitis (male 13, female 16), aged 21-47 years (33 ± 11). Disease activity was assessed by Truelove-Writeria. Patients with a score of above 5 were regarded as having active colitis. Twenty healthy people (male 12, female 8), aged 19-53 years (31 ± 14), served as normal controls. Blood samples were taken from an antecubital vein puncture. Blood (1.8 mL) was injected into the tubes containing sodium citrate (0.13 mmol/L). The plasma was obtained by centrifugation at 3000 r·min^-1 for 10 min, and stored at -80 °C until assayed by ELISA.

RESULTS: The mean plasma levels of DD and vWF in active UC patients were significantly higher than those of the controls (0.69 ± 0.41 vs 0.27 ± 0.11, P < 0.01; 143 ± 46 vs 103 ± 35, P < 0.01). The mean plasma levels of DD in the patients with active disease were higher than those with inactive disease (0.69 ± 0.41 vs 0.48 ± 0.29, P < 0.05). The levels of vWF were not different between active and inactive patients. DD levels were positively related to vWF levels (r = 0.574, P < 0.01). There was no significant difference between levels of DD and vWF and the scope of disease and sex of the patients.

CONCLUSION: vWF is an important feature and a good marker of UC; intravascular thrombus and endothelial cell dysfunction were found in UC patients; and the combined test of DD and vWF is helpful to distinguish the activity of the UC patients.

Serum hepatocyte growth factor concentration is correlated with the forearm vasodilator response in hypertensive patients

To evaluate the clinical importance of serum hepatocyte growth factor (HGF) concentration, we designed two clinical investigations. The first study analyzed the correlation between serum HGF concentration and clinical arterial stiffness or the vasodilator response to reactive hyperemia in hypertensive patients. The second study investigated the correlation between changes in serum HGF concentration and clinical arterial stiffness or reactive hyperemia during treatment with cilazapril or atenolol. A total of 210 hypertensive patients were analyzed in the first study, and 25 patients with essential hypertension were evaluated in the second study. Pulse wave velocity (PWV), strain gauge plethysmography, and serum HGF concentration were measured in the first study. We also evaluated these factors before and after treatment with either cilazapril (2.0 mg/day) or atenolol (25 mg/day) for 6 months in the second study. Serum HGF concentration was negatively correlated to reactive hyperemia in overall (r = 0.434, P < .0001) and nontreatment (r = 0.452, P < .0001) hypertensive patients. Arterial stiffness was weakly related to serum HGF concentration (P < .05) after adjusting for age and mean blood pressure (BP). By multiple regression analysis, only serum HGF concentration showed a strong independent correlation with reactive hyperemia, age and mean BP with PWV. Moreover, a relationship between endothelium-dependent vasodilation and serum HGF concentration was observed during treatment with cilazapril or atenolol (r = 0.406, P < .005). These results suggest that in evaluation of serum HGF concentration, the forearm vasodilator response to reactive hyperemia and PWV might be useful for managing hypertension in patients who are receiving antihypertensive therapy.