Protein C in patients with alcoholic cirrhosis and other liver diseases

Factor VIII/protein C ratio independently predicts liver-related events but does not indicate a hypercoagulable state in ACLD

BACKGROUND & AIMS

It has been suggested that the ratio of procoagulant factor VIII to anticoagulant protein C (FVIII/PC) reflects the hemostatic equilibrium. Moreover, FVIII/PC predicted decompensation/death in a small study not accounting for portal hypertension severity. We investigated (i) the prognostic value of FVIII/PC (outcome-cohort) and (ii) whether FVIII/PC reflects the hypercoagulable state (assessed by thrombomodulin-modified thrombin generation assay [TM-TGA]) or the risk of bleeding/thrombotic events in patients undergoing hepatic venous pressure gradient (HVPG) measurement during follow-up.

METHODS

(i) The outcome-cohort comprised 576 patients with evidence of advanced chronic liver disease (liver stiffness measurement ≥10 kPa and/or HVPG ≥6 mmHg). (ii) TM-TGA-cohort patients (n = 142) were recruited from the prospective VIenna CIrrhosis Study (VICIS: NCT03267615).

RESULTS

(i) FVIII/PC significantly increased across clinical stages (p <0.001) as well as HVPG (p <0.001) and MELD score (p <0.001) strata and remained independently associated with decompensation/liver-related death (adjusted hazard ratio 1.06; 95% CI 1.01-1.11; p = 0.013), even after multivariable adjustment. It was also associated with acute-on-chronic liver failure (ACLF) development (adjusted hazard ratio 1.10; 95% CI 1.02-1.19; p = 0.015) in patients with decompensated cirrhosis. (ii) FVIII/PC showed a weak positive correlation with endogenous thrombin potential (Spearman's ρ = 0.255; p = 0.002), but this association disappeared after adjusting for the severity of liver disease. FVIII/PC was not associated with the development of bleeding (p = 0.272) or thrombotic events (p = 0.269). However, FVIII/PC correlated with biomarkers of different pathophysiological mechanisms that promote liver disease progression.

CONCLUSION

FVIII/PC provides prognostic information regarding hepatic decompensation/death and ACLF, independently of established prognostic indicators. However, this is not evidence that hypercoagulability drives disease progression, as the correlation between FVIII/PC and thrombin generation is confounded by liver disease severity and FVIII/PC was not associated with thrombosis. Therefore, FVIII/PC does not reflect coagulation and results from previous studies on FVIII/PC require re-interpretation.

CLINICAL TRIAL NUMBER

NCT03267615 (in part).

LAY SUMMARY

A balanced coagulation system is essential for preventing bleeding episodes and blood clot formation (thrombosis). Blood of patients with advanced liver disease may have increased coagulation potential, possibly promoting the worsening of liver disease via thrombosis in the blood vessels of the liver. The ratio between the results of 2 blood tests (procoagulant factor VIII to anticoagulant protein C) has been suggested to reflect these increases in coagulation potential. Our study demonstrates, on the one hand, that this ratio is a versatile predictor of the development of complications of cirrhosis, yet on the other hand, that it is unrelated to coagulation.

Translational insight into prothrombotic state and hypercoagulation in nonalcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is an emerging and threatening pathological condition, ranging from fatty liver (FL) to chronic steatohepatitis (NASH), liver cirrhosis, and eventually to hepatocellular carcinoma (HCC). Recent findings suggest that patients with NAFLD have a higher risk of cardiovascular events and thromboembolism and that this risk is independent of metabolic diseases that are frequently associated with NAFLD, such as diabetes, hyperlipidaemia, and obesity. The vascular involvement of NAFLD might be considered its systemic burden, conditioning higher mortality in patients affected by the disease. These clinical findings suggested the existence of a prothrombotic state in NAFLD, which is partially unexplored and whose underlying mechanisms are to date not completely understood. Here, we review the mechanisms involved in the pathogenesis of the prothrombotic state in NAFLD across the progression from the healthy liver through the different stages of the disease. We focused on the possible role of several metabolic features of NAFLD possibly leading to hypercoagulation other than endothelial and platelet activation, such as insulin-resistance, nitric oxide production regulation, and gut microbiota homeostasis. Also, we analysed the involvement of plasminogen activator inhibitor-1 (PAI-1) and thromboinflammation taking place in NAFLD. Finally, we described factors striking a prothrombotic imbalance in NASH cirrhosis, with a particular focus on the pathogenesis of portal vein thrombosis.

Coagulation status of critically ill patients with and without liver disease assessed using a novel thrombin generation analyzer

The liver synthesizes the majority of pro- and anti-coagulant and fibrinolytic proteins, and during liver dysfunction synthesis of these proteins is reduced. The end point of conventional hemostatic tests, such as the prothrombin time (PT), occurs when only 5% of thrombin generation (TG) has taken place and is not sensitive to the effects of natural anti-coagulants. The aim of this study was to determine whether TG in the presence of thrombomodulin (TM) provides more useful information about coagulation potential, in comparison to the PT. Analysis was performed on ST Genesia, a novel TG analyzer from Diagnostica Stago. TG was measured using STG-Thromboscreen, a reagent containing an intermediate concentration of human tissue factor (TF) ± rabbit TM to account for anti-coagulant protein C (PC) activity. Platelet-poor plasma (PPP) samples were from the Intensive Care Study of Coagulopathy-2 (ISOC-2), which recruited patients admitted to critical care with a prolonged PT (3 seconds above the reference range). Despite a prolonged PT, 48.0% and 60.7% of patients in the liver and non-liver groups had TG parameters within the normal range. Addition of TM reduced TG by 34.5% and 41.8% in the liver and non-liver groups, respectively. Interestingly, fresh frozen plasma (FFP) transfusion had no impact on TG. Measurement of TG with addition of TM provides a more informative assessment of coagulation capacity and indicates that hemostasis is balanced in patients with liver disease during critical illness, despite conventional tests suggesting that bleeding risk is increased.

Protein C Deficiency in Chronic Hepatitis C

There is accumulating evidence that the coagulation system is involved in the process of fibrogenesis in chronic liver disease. Recent studies postulated a possible connection between plasmatic hypercoagulability and progression of fibrosis. The aim of the study was to investigate disorders of the coagulation system in patients with chronic hepatitis C having different extent of hepatic fibrosis well defined by liver histology. A total of 62 patients with chronic hepatitis C were recruited and categorized into 2 groups according to their histological fibrosis stage : mild/moderate fibrosis group (F0-F3 group, n = 30) and extensive fibrosis/cirrhosis group (F4-F6 group, n = 32). The control group consisted of 31 healthy individuals. The following hemostatic assays were evaluated: antithrombin III (AT), protein C (PC) activity, activated partial thromboplastin time, prothrombin time, plasma fibrinogen as well as conventional liver function test. The PC level exhibited a significant reduction in both patient groups when compared to the normal control group (89.25% ± 10.05% and 48.33% ± 15.86% vs 111.86 ± 10.90; P < .001 and P < .001). The PC was found to be the strongest associated factor to histological fibrosis stage ( r = –.834; P < .0001). Univariate and multivariate analysis showed that AT ( P = .003) and PC ( P = .0001) were the most important factors associated with advanced fibrosis. The PC ( P = .001) was found to be the only predictor of mild fibrosis. In conclusion, PC deficiency occurs in an early stage of liver fibrosis. The severity of deficiency is proportional to extent of fibrosis. The PC may have a key role in linking hypercoagulability with hepatic fibrogenesis in chronic liver disease.

Impact of sustained virus elimination on natural anticoagulant activity in patients with chronic viral hepatitis C

Previous studies have reported reduced synthesis of various hemostatic factors in patients with chronic liver disease. Whether changes in plasma levels of these proteins reflect recovered liver synthetic function following virological eradication therapy has not been approved yet. The aim of the study was to determine the impact of sustained viral suppression achieved with pegylated interferon alpha and ribavirin on hemostatic parameters including natural anticoagulants in patients with chronic hepatitis C. The following coagulation screening tests were obtained in thirty patients with chronic viral hepatitis C before and after completion of antiviral treatment: activated partial thromboplastin time, prothrombin time, plasma fibrinogen and natural anticoagulant proteins antithrombin III, protein C (PC) and total protein S (PS) activity. Only patients who achieved durable virus suppression were included. The mean PC and PS levels were significantly lower in patients with chronic viral hepatitis C before antiviral therapy than in healthy controls (79.04 ± 16.19 % vs. 109.92 ± 21.33% and 54.04 ± 16.11% vs. 87.60 ± 8.15%, respectively; (p<0.001). Mean levels of PC exhibited a significant increase by 14.69 % after the completion of antiviral treatment (93.73 ± 14.18%, p<0.001) as well as PS levels, which significantly increased by 21.46% (75.50 ± 15.43, p<0.001) when compared with pre-treatment values. No remarkable fluctuations in other hemostatic parameters were noted. Protein C and protein S are sensitive markers of hepatocyte synthetic impairment and are valuable markers in monitoring the efficacy of antiviral treatment in chronic hepatitis C patients. Larger studies are needed to confirm our results.

Pelvic adhesion and gonadotropin-releasing hormone analogue: effects of triptorelin acetate depot on coagulation and fibrinolytic activities

The study investigated the impact of gonadotropin-releasing hormone analogue (GnRH-a) on coagulation and fibrinolytic activities and its effectiveness in the prevention of pelvic adhesion after myomectomy. Thirty-two infertile women underwent myomectomy followed by adhesion evaluation surgery with a second-look laparoscopy. Before myomectomy, 15 women were treated with triptorelin acetate for 3 months and 17 received no treatment. Plasminogen activator inhibitor (PAI), thrombin activatable fibrinolysis inhibitor (TAFI), protein C (PC), plasminogen, α2-antiplasmin were determined by enzyme-linked immunosorbent assays and the activity of coagulation factors V and VIII by coagulometric methods. Patients treated with GnRH-a showed significant decrease in PAI, TAFI, factors V, and VIII (P < .05) and increased PC (P < .05), but no significant change in plasminogen and α2-antiplasmin levels compared with control group. The incidence, extent, and severity of adhesions were significantly lower in GnRH-a-treated patients compared with control group (P < .05), suggesting a possible critical role of the GnRH-a therapy in preventing postoperative adhesion development.

Liver cirrhosis is associated with venous thromboembolism among hospitalized patients in a nationwide US study

BACKGROUND & AIMS

Studies on the impact of liver disease on venous thromboembolism (VTE) have produced conflicting results. We assessed the risk of VTE in patients with compensated or decompensated cirrhosis.

METHODS

Data on hospital discharges of patients with liver cirrhosis and a random sample of control patients (without liver disease, 1%) were analyzed from the Nationwide Inpatient Sample (1998-2006). Prevalence of VTE was compared among patients with and without cirrhosis. The impact of VTE on in-hospital mortality and length of stay (LOS) was assessed.

RESULTS

After multivariate adjustment, patients with compensated and decompensated cirrhosis were at higher risk of VTE until the age of 45 years (odds ratio [OR], 1.23; 95% confidence interval [CI], 1.04-1.46 and OR, 1.39; 95% CI, 1.15-1.69, respectively). After 45 years of age, compensated cirrhosis was associated with a modest decrease in adjusted odds of VTE (OR, 0.90; 95% CI, 0.85-0.95) whereas decompensated cirrhosis was not associated with higher risk of VTE (OR, 0.97; 95% CI, 0.91-1.04). VTE was associated with increased mortality among patients with compensated cirrhosis (OR, 2.16; 95% CI, 1.96-2.38) or decompensated cirrhosis (OR, 1.66, 95% CI, 1.47-1.87). VTE was associated with a 103% increase in length of stay (95% CI, 95%-111% increase) among patients with compensated cirrhosis and an 86% increase (95% CI, 78%-94% increase) among those with decompensated cirrhosis.

CONCLUSIONS

Patients with cirrhosis under the age of 45 years are at higher risk for VTE that those without liver disease and should be considered for VTE prophylaxis.

Study of plasma protein C and inflammatory pathways: biomarkers for dimethylnitrosamine-induced liver fibrosis in rats

The present investigation was designed to identify potential biomarker(s) and assess the involvement of inflammatory pathway in dimethylnitrosamine (DMN)-induced liver fibrosis in rats. Following DMN-treatment (10 mg/ml/kg, i.p., given three consecutive days each week for 4 weeks) body and liver weights were significantly decreased concurrent with increasing severity of liver damage assessed by bridging fibrosis, a histopathologic assessment and characteristic of human liver disease. Protein C along with albumin, C-reactive-protein (CRP), haptoglobin and total protein were significantly reduced and correlated with changes in liver histopathology. Biochemical markers of liver functions were significantly increased and correlated with changes in liver histopathology and plasma levels of protein C. Soluble intracellular-adhesion-molecule-1 (sICAM-1) levels were increased significantly but were poorly correlated with histopathology and protein C levels. Inflammatory chemokines and other analytes, monocyte-chemoattractant-protein-1 and 3 (MCP-1 and MCP-3), macrophage-colony-stimulating-factor (M-CSF) were significantly increased during the disease progression, whereas macrophage-derived-chemokine (MDC) and CRP were significantly suppressed. Circulating neutrophils and monocytes were also increased along with disease progression. The differential changes in sICAM-1, hyaluronic acid, gamma-glutamyltranspeptidase (GGT), neutrophil and other inflammatory chemokines suggest the involvement of inflammatory pathways in DMN-induced liver fibrosis. In conclusion, the progressive changes in protein C along with other noninvasive biochemical parameters whose levels were significantly correlated with disease progression may serve as biomarkers for pharmacological assessment of targeted therapy for liver fibrosis.

Intracellular retention of hepatic serpins caused by severe hyperlipidemia

BACKGROUND

High levels of circulating lipids contribute to both the development of non-alcoholic liver steatosis (NALS) and peripheral arterial disease, leading to increased thrombotic risk. However, the effects of hyperlipidemia on hepatic proteins have barely been studied. Antithrombin is a hepatic serpin with anticoagulant and anti-inflammatory roles. The conformational flexibility of antithrombin renders it susceptible to both, genetic and posttranslational modifications. Thus, mutations and environmental factors have been shown to alter this molecule.

METHODS

We used a chick model to assess the effects of hyperlipidemic diets (HD) on this conformationally sensitive molecule. We determined antithrombin activity in plasma and evaluated the histological and immunohistological features of livers from these animals.

RESULTS

A HD for 6 months led to a significant intrahepatic retention and aggregation of antithrombin, which correlated with hepatic steatosis, as revealed by immunohistological analysis. Accordingly, a decrease in circulating antithrombin activity (48.71 +/- 6.35%) was observed. Other hepatic proteins, including heparin cofactor II, another anticoagulant serpin, also accumulated intracellularly. Atorvastatin and reversion to a normal diet after 3 months partially protected livers from these deleterious effects.

CONCLUSIONS

Our results support that hyperlipidemia-induced NALS causes a significant intracellular aggregation of hemostatic serpins in liver, which determines a decrease in their circulating levels.

Haemostatic abnormalities in liver disease: could some haemostatic tests be useful as liver function tests?

The liver plays a central role in haemostasis, being the site of synthesis of most of the clotting factors, coagulation inhibitors and fibrinolytic parameters, in addition to its clearance of activated clotting and fibrinolytic factors. Nonetheless, no haemostatic test(s) is included among the routine liver function tests and this study aims to probe this possibility. The liver disease group (n=258) included acute hepatitis (n=25), chronic viral hepatitis (n=128), hepatitis B (HB) carriers (n=25), liver cirrhosis (n=67), and hepatocellular carcinoma (HCC) (n=13). The prothrombin time was significantly prolonged in acute hepatitis, liver cirrhosis and HCC. However, the reptilase time was prolonged in all the groups except in HB carriers, while the thrombin time was prolonged only in the HCC group. Antithrombin III and protein C levels exhibited significant reduction in acute hepatitis, liver cirrhosis and HCC. On the other hand, protein S levels (total and free) were reduced significantly in all the patients groups, including HB carriers when compared with healthy controls. Derangement of haemostatic tests is a common feature in liver disease, being most significant in acute hepatitis, liver cirrhosis and hepatocellular carcinoma. The most sensitive markers of hepatocyte malfunction are protein S (total and free) and the reptilase time as they were abnormal, in the mildest liver affections, when other biochemical tests as well as other haemostatic tests were normal. Further studies are needed to see whether these two tests qualify for inclusion among the routine liver function tests.

Coagulation inhibitors in alcoholic liver cirrhosis

In the present study we have analyzed the relationship between coagulation inhibitors (antithrombin III, protein C and S, thrombomodulin), liver function impairment, and plasma activity of the endothelium-derived proteins plasminogen activator (t-PA) and plasminogen activator inhibitor (PAI-1) in 27 alcoholic cirrhotic patients and 25 controls. Cirrhotics showed decreased values of all the mentioned parameters except for thrombomodulin, PAI-1, and t-PA. Thrombomodulin and t-PA levels were higher in cirrhotics. No relationship was observed between thrombomodulin and t-PA or PAI-1. Protein C and antithrombin III levels were significantly lower in Child's C patients, whereas no correlation was found between t-PA and thrombomodulin and hepatic function derangement. PAI-1 activity was normal in our patients.