Prevalence of hyperfibrinolysis in patients with liver cirrhosis

The Role of Endothelial Dysfunction in the Pathogenesis of Pregnancy-Related Pathological Conditions: A Review

In the recent decades, endothelial dysfunction (ED) has been recognized as a significant contributing factor in the pathogenesis of many pathological conditions. In interaction with atherosclerosis, hypercholesterolemia, and hypertension, ED plays a crucial role in the pathogenesis of coronary artery disease, chronic renal disease, and microvascular complications in diabetes mellitus. Although ED plays a significant role in the pathogenesis of several pregnancy-related disorders such as preeclampsia, HELLP syndrome, fetal growth restriction, and gestational diabetes mellitus, the exact pathogenetic mechanisms are still a matter of debate. The increased prevalence of these entities in patients with preexisting vascular diseases highlights the essential pathological role of the preexisting ED in these patients. The abnormal uteroplacental circulation and the release of soluble factors from the ischemic placenta into the maternal bloodstream are the main causes of the maternal ED underlying the characteristic preeclamptic phenotype. Besides the increased risk for maternal and fetal poor outcomes, the preexisting ED also increases the risk of development of future cardiovascular diseases in these patients. This study aimed to look deeper into the role of ED in the pathogenesis of several pregnancy-related hypertensive and liver diseases. Hopefully, it could contribute to improvement of the awareness, knowledge, and management of these conditions and also to the reduction of the adverse outcomes and additional long-term cardiovascular complications.

Hyperfibrinolysis in liver disease

The incidence of hyperfibrinolysis in patients with cirrhosis is still debated. The reasons for this uncertainty probably lie in the lack of appropriate laboratory tests for its evaluation. There is a relative consensus, however, that hyperfibrinolysis can complicate the clinical course of liver cirrhosis, especially in cases of moderate to severe liver failure. Hyperfibrinolysis correlates positively with the severity of underlying liver disease, and low-grade systemic fibrinolysis is found in 30% to 46% of patients who have end-stage liver disease. Accelerated intravascular coagulation with secondary hyperfibrinolysis has been reported in patients who have liver failure. Hyperfibrinolysis may delay primary hemostasis, thereby aggravating variceal bleeding and facilitating recurrence.

Induction of hepatic tissue-type plasminogen activator and type 1 plasminogen activator-inhibitor gene expressions and appearance of their translation products in the bile following acute liver injury in rats

BACKGROUND/AIMS

The plasminogen activator (PA)-plasmin system is primarily involved in fibrinolysis, but is also in the patho/physiological events in which breakdown of extracellular matrices is evoked topically. In this present study, we examined the expression of fibrinolytic factors, tissue-type PA (t-PA) and Type 1 PA inhibitor (PAI-1), in acute liver injury.

METHODS

Acute liver injury was produced in rats by the intraperitoneal administration of carbon tetrachloride (CCl(4)). Plasma aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities were measured to verify the hepatocellular damage. t-PA and PAI-1 gene expressions were measured by Northern blotting, and the cell type(s) expressing these genes was identified by in situ hybridization. t-PA and PAI-1 levels were measured by enzyme-linked immunosorbent assay (ELISA).

RESULTS

A single intraperitoneal administration of CCl(4) caused severe acute parenchymatous liver injury. Both t-PA and PAI-1 gene expressions were induced by the acute liver injury, and plasma t-PA and PAI-1 concentrations were also increased. In situ hybridization studies demonstrated that the hepatocytes were the cells expressing t-PA and PAI-1 genes during the acute liver injury. t-PA was also augmented in the bile, whereas PAI-1 was decreased there.

CONCLUSIONS

t-PA and PAI-1 gene expressions are induced in the hepatocytes of rats with acute liver injury. These fibrinolytic factors induced by liver injury may play important roles in liver regeneration.

Association between low-grade disseminated intravascular coagulation and endotoxemia in patients with liver cirrhosis

BACKGROUND & AIMS

Hyperfibrinolysis may complicate the clinical course of liver cirrhosis. The aim of this study was to evaluate if, in cirrhosis, hyperfibrinolysis is primary or secondary to intravascular clotting activation and if endotoxemia is associated with activation of clotting and/or the fibrinolytic system.

METHODS

Clotting, fibrinolytic indexes, and endotoxemia were studied in 41 cirrhotic patients and 20 healthy subjects.

RESULTS

Twenty-seven cirrhotic patients (66%) had high plasma levels of prothrombin fragment F1 + 2, a marker of thrombin generation. Nineteen patients had elevated values of D-dimer, a marker of fibrinolysis in vivo. All patients with high values of D-dimer also had high values of prothrombin fragment F1 + 2. Endotoxemia was elevated in patients with severe liver failure and significantly correlated to prothrombin fragment F1 + 2. Thirty patients were treated for 7 days either with standard therapy (n = 15) or with standard therapy plus nonabsorbable antibiotics (n = 15). Although standard therapy did not significantly change laboratory indexes, a significant reduction of endotoxemia, prothrombin fragment F1 + 2, and D-dimer was found in those patients who received the combined treatment.

CONCLUSIONS

This study shows that, in cirrhotic patients, hyperfibrinolysis is not a primary phenomenon but occurs as a consequence of clotting activation and that endotoxemia might play a pathophysiological role.

Heterozygous protein C deficiency and dysfibrinogenemia acquired by liver transplantation

Orthotopic liver transplantation is now a successful treatment for end-stage liver diseases. Since most components of the coagulation system are synthesized by liver parenchymal cells, there is always a risk of genetic defects of hemostasis being transmitting by liver transplantation. Some coagulation factor defects, such as protein C deficiency, do not induce abnormalities in routine coagulation tests and, thus, go undetected before organ procurement. We report the first case, to our knowledge, of the transmission of heterozygous protein C deficiency, an autosomal recessive genetic defect, associated with dysfibrinogenemia, an autosomal dominant trait, by liver transplantation. Both the recipient and the donor presented with severe thrombotic complications. This case shows that potentially morbid genetic defects can be transmitted by organ transplantation, and it emphasizes the difficulty associated with organ procurement criteria, particularly for liver transplantation, in which routine blood tests appear insufficient for determining whether or not organs can or should be procured from a given donor.

Assessment of Relative Contributions of Fibrinolysis and Fibrinogenolysis to the Abnormalities of Plasma Fibrinogen/Fibrin-Retated D and E Antigens and Their Ratio in Liver Cirrhosis

Many pathogenic mechanisms play a part in hemorrhage in chronic liver disease. This study was done to characterize the alterations of fibrinogen components and dysfibrinogenemia in patients with liver cirrhosis. Plasma from 31 patients with liver cirrhosis was analyzed to determine the fibrinogen/fibrin-related D and E antigens by latex photometric immunoassay; fibrinogen by the Clauss method; fibrinogen degradation product (FgDP), protein C antigen, and tissue plasminogen activator (tPA) by enzyme immunoassay; and antithrombin III by the colorimetric method, respectively. Reptilase, time and fibrin monomer (FM) tests were also done. Fibrinogen/fibrin-related D and E antigens were higher and their ratio (D/E) was lower in liver cirrhosis compared with normal subjects. Fibrinogen levels were inversely correlated with D (p = 0.0001) and E (p = 0.0001) antigenic levels in plasma. FgDP levels were not significantly correlated with D and E levels. However, semiquantitative D-dimer levels had significant association with D and E levels. Reptilase time was abnormally prolonged in all patients with high D and E levels, and FM tests were also positive in most patients with increased levels of D and E. Protein C antigen levels were inversely correlated with D (p = 0.0110) and E (p = 0.0112) concentrations but were well correlated with clottable fibrinogen concentrations (p = 0.0058). Hypercoagulability followed by pathologic activation of fibrinolysis, rather than synthesis of abnormal fibrinogen molecules, may contribute to hemorrhage. Not only true hypofibrinogenemia due to the decreased synthesis of intact fibrinogen but also elevated levels of these antigens may be clinically significant in the treatment of cirrhotic patients at risk of bleeding. Protein C may play an important regulatory role in fibrinolysis.

A photometric method for the dosage of factor XIII applied to the study of chronic hepatopathies

The photometric method of Fickenscher et al. for the determination of factor XIII (FXIII) activity has been used in the study of 35 patients with severe chronic hepatopathy, in comparison with 25 normal subjects. The FXIII proteic fractions a and b were determined by quantitative immuno-electrophoresis after Laurell. The plasmatic FXIII activity, as well as the proteic fractions a and b, were significantly reduced in hepatopatic patients, in comparison to controls, and proportional to the prolongation of prothrombin times. Ratios between functional and immunological levels of FXIII in hepatopatics were similar to those observed in controls. These results confirm the involvement of fibrin stabilization deficiency in the coagulation defect of severe chronic hepatopathies. The correlations between functional and antigenic values are in agreement with the hepatic origin of FXIII. The method of Fickenscher has been proved to be rapid and simple, and it may be useful in the routine study of hepatopathies, for a better knowledge of the role of FXIII deficiency in the complex coagulopathy of liver diseases, as well as of other acquired FXIII deficiencies.