Fibrinolysis and Fibrinogenolysis in Disseminated Intravascular Coagulation

Proposal for new diagnostic criteria for DIC from the Japanese Society on Thrombosis and Hemostasis

Disseminated intravascular coagulation (DIC) is a serious disease that, in the presence of underlying disease, causes persistent, generalized, marked coagulation activation. Early treatment based on an appropriate diagnosis is very important for improving patients’ prognosis, to which end diagnostic criteria play a key role. Several criteria have been proposed, but each has its strengths and weaknesses, and improved criteria are needed. Widespread use of coagulofibrinolytic markers has elucidated that the pathology of DIC differs greatly as a function of the underlying disease. Thus, discriminating use of DIC diagnostic criteria that take underlying diseases into account is important.

DIC diagnostic criteria that are well known in Japan include the Japanese Ministry of Health and Welfare’s old DIC diagnostic criteria (JMHW criteria), the International Society on Thrombosis and Haemostasis’s DIC diagnostic criteria (ISTH criteria), and the Japanese Association for Acute Medicine’s acute-stage DIC diagnostic criteria (JAAM criteria). Those criteria have their respective drawbacks: the sensitivity of the ISTH criteria is poor, the JAAM criteria cannot be applied to all underlying diseases, and the JMHW criteria have poor sensitivity in the case of infections, do not use molecular markers, and result in misdiagnosis. The Japanese Society on Thrombosis and Hemostasis’s newly proposed provisional draft DIC diagnostic criteria (new criteria) use diagnostic criteria classifications of “hematopoietic disorder type”, “infectious type”, and “basic type” based on the underlying pathology. For the hematopoietic disorder type the platelet count is omitted from the score, while for the infectious type, fibrinogen is omitted from the score. Also, points are added if the platelet count decreases with time. In the new criteria, molecular markers and antithrombin activity have been newly included, and as a countermeasure for misdiagnosis, 3 points are deducted if there is liver failure. In this paper, we discuss various problems encountered with DIC diagnosis, and we describe the new criteria together with the events that led to their creation.

These new diagnostic criteria take into account the underlying diseases of wide area, and we expect that they will serve clinicians well due to the above adaptations and improvements.

Implications of fibrinogenolysis in patients with closed head injury

The objective of this study was to determine the clinical significance of fibrinogenolysis in patients with isolated closed head injury. We correlated indices of fibrinolytic activity, fibrinogen degradation products (FgDP), and fibrin degradation products (FbDP) with outcome in order to accomplish this. This study consisted of 40 patients with isolated closed head trauma in whom blood sampling could be initiated within 3 h after injury. Patients were divided into two groups according to Glasgow Outcome Scale status at 3 months after injury, characterized as good recovery or moderate disability (group 1, n = 21); and severe disability, vegetative, or death (group 2, n = 19). The plasma fibrinogen concentration correlated with the Glasgow Coma Scale score on admission (r2 = 0.201, p < 0.01), and plasma fibrinogen concentrations in group 2 were lower than in group 1 (p < 0.05). Plasma concentrations of fibrin/fibrinogen degradation products (FDP) and plasmin-alpha2-plasmin inhibitor complex (PIC), molecular markers of activation of fibrinolysis, were higher in group 2 than in group 1 (p < 0.001), and both FgDP and FbDP concentrations in group 2 also were higher than in group 1 (p < 0.001). Both the FgDP and FbDP concentrations correlated with the PIC concentration. Moreover, the plasma FgDP concentrations correlated inversely with alpha2-plasmin inhibitor activity, a potent inhibitor of the fibrinolytic sysytem, as did the FbDP concentration. This study reveals that both fibrinolysis and fibrinogenolysis are involved in the coagulopathy that develops during the acute phase of head injury and correlate with fibrinolytic activity. Decreased activity of alpha2-plasmin inhibitor may contribute to fibrinogenolysis.

The effects of green pit viper (Trimeresurus albolabris and Trimeresurus macrops) venom on the fibrinolytic system in human

Green pit viper (Trimeresurus albolabris and Trimeresurus macrops) venom was found to have a thrombin-like effect in vitro but cause a defibrination syndrome in vivo. The effects of venom on fibrinolytic system have not been well characterized. This knowledge can help to define the roles of antifibrinolytic therapy, give insights in fibrinolytic system regulation and potentially lead to identification of a new profibrinolytic agent from this venom. Forty-six cases of green pit viper bites were studied for various coagulation and fibrinolytic parameters and correlated with serum venom levels measured by ELISA. Fibrinolytic system activation is very common as indicated by low plasminogen (50%), low antiplasmin (56.5%) and elevated fibrin-fibrinogen degradation products (FDPs, 97.4%) levels. FDP test is very sensitive and a normal level is useful for exclusion of systemic envenomation. In contrast to some other models of defibrination syndrome, such as Russell viper (Daboia russelli siamensis), elevation of plasminogen activator activity (PA) was found indicating a hyperfibrinolytic state. Definite increase in tissue-type plasminogen activator (t-PA) antigen (p = 0.00075) with a modest elevation of its inhibitor plasminogen activator inhibitor-1 (PAI-1) (p = 0.27) probably contributes to this effect. This supports the idea that the balance between plasminogen activators and inhibitors can determine fibrinolytic responses in pathologic states. Fibrinopeptide A levels were markedly elevated (68.43 +/- 51.57 ng/ml in cases and 2.83 +/- 3.80 ng/ml in control, p < 0.0001) and correlated well with clinical severity suggesting that the fibrin deposition from the thrombin-like effect is the main mechanism of fibrinolysis. Therefore, antifibrinolytic agents probably have no role in treatment. However, the components of green pit viper venom that have these profibrinolytic effects in human are interesting and should be further identified.

Effects of early plasmin digests of fibrinogen on isometric tension development in isolated rings of rat pulmonary artery

The purpose of the study was to determine the effects of early plasmin-mediated digests of rat fibrinogen on the vascular tone of rat pulmonary artery in order to compare with reported vasoactive effects of high levels of isolated human peptides in various rat vascular beds. Isometric tension was monitored in isolated rings of rat pulmonary artery precontracted with phenylephrine (4 x 10(-8) mol). Fibrinogen degradation products (FgDPs) were produced by digestion of rat fibrinogen with plasmin to 1, 2, 3 and 60 minutes whereupon the digestion was stopped by addition of Trasylol. These FgDPs were added to the tissue bath to achieve final concentrations of 6.7, 13.3, 26.7 and 53.3 micrograms/mL i.e. values similar to those found in vivo during thrombolytic therapy for myocardial infarction. Results were expressed as a percentage of a maximal contraction elicited in each ring in response to phenylephrine (10(-5) M). The early FgDP fractions, at these pathophysiological concentrations, did not induce significant change in isometric tension in the isolated pulmonary arterial rings (P > 0.05, ANOVA).

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.

Fibrinogen/fibrin degradation products and D-dimer in clinical practice: interpretation of discrepant results

In clinical practice, occasionally some patients show dissociated values of fibrinogen/fibrin degradation products (FDP) and D-dimer (cross-linked fibrin degradation products). In an attempt to assess the frequency, clinical backgrounds, and hemostatic states of these cases, FDP and D-dimer were simultaneously measured together with other hemostatic parameters in 371 samples from patients with various diseases. As a whole, FDP were elevated in parallel with the progress of activation of blood coagulation and fibrinolysis. However, in patients with elevated FDP and/or D-dimer, 11.5% of samples showed relatively lower D-dimer values than those expected from FDP levels, and these were regarded as an apparently dissociated group. In the dissociated group, activation of coagulation and fibrinolysis occurred to a lesser extent than others. Analysis of these samples suggested that the possible reasons for the dissociation between FDP and D-dimer values were accelerated fibrinogenolysis with or without secondary fibrinolysis, accelerated fibrinogenolysis by non-plasmic proteinases, elevated soluble fibrin, and possibly false-positive FDP levels due to unclottable fibrinogen remaining in the serum samples. In practice, simultaneous measurements of FDP and D-dimer are useful for more accurate estimation of hyperfibrinolytic states.

Plasma urokinase-type plasminogen activator in patients with leukemias

Plasma levels of urokinase-type plasminogen activator (u-PA) were measured with an enzyme-linked immunosorbent assay in patients with leukemias. As compared with healthy subjects (0.73 +/- SD 0.17 ng/ml), plasma u-PA antigen level was markedly elevated in patients with acute promyelocytic leukemia (APL) (1.76 +/- 0.89 ng/ml) at disease onset. Mean u-PA concentrations in patients with other acute nonlymphoblastic leukemia (0.57 +/- 0.51 ng/ml), acute lymphoblastic leukemia (0.77 +/- 0.82 ng/ml) and chronic myelocytic leukemia in blastic crisis (1.30 +/- 1.35 ng/ml) were not significantly elevated, but some of them showed an elevation of plasma u-PA. Plasma u-PA values were correlated with some of the fibrinolytic parameters such as FDP and D-dimer. Plasma u-PA antigen was decreased after the administration of antileukemic drugs in patients with APL. These results suggest that the coagulopathy in patients with various leukemias may in part be associated with u-PA release from the leukemic cells, especially in patients with APL.

What is the best treatment for acute promyelocytic leukemia?

The modern treatment of acute myelogenous leukemia (AML), consists of a polychemotherapeutic induction treatment followed by a post-remission therapy of variable intensity and duration and acute promyelocytic leukemia (APL) does not differ from this behavior. However, differently from the other AML subtypes, APL shows a high response rate to induction monochemotherapies with anthracycline drugs. This high response rate to anthracycline monochemotherapies is very peculiar of APL. Moreover, it has been suggested that maintenance treatment regimens incorporating the drugs Methotrexate and 6-Mercaptopurine, two drugs generally not utilized in the post-remission treatment of other AML subtypes, may be effective in prolonging the leukemia-free survival of APL. Furthermore, the results firstly obtained by a Chinese group in 1988 by using the vitamin A derivative all-trans retinoic acid (ATRA) have been successively confirmed by several other groups in the world. Therefore, at present the all-trans retinoic acid appears to be the best CR inducer in APL. However, these CRs are short lasting when maintained with ATRA alone and eventually all patients relapse. As a consequence, patients achieving CR with ATRA still require intensive post-remission chemotherapy to maintain the CR. As for bone marrow transplantation procedures, it is our opinion that they do not represent the treatment of choice of APL in first CR considering the very good results obtained with standard pharmacological approaches. In conclusion, only future randomized prospective trials will clarify which, among the several proposed therapeutic approaches, should be preferred in this very peculiar subtype of AML.

Plasmin generation and fibrin(ogen)olysis following desmopressin infusion

Desmopressin acetate (DDAVP) is known to stimulate the release of tissue-type plasminogen activator (t-PA) from endothelial cells, but it is unclear whether the increased t-PA actually elicits the plasmin generation and fibrin(ogen)olysis in the circulating blood. We measured plasma levels of plasmin-alpha 2-plasmin inhibitor complex, fibrinogen degradation products (FgDP) and fibrin degradation products (FbDP) following desmopressin infusion in 19 patients with bleeding disorders or thrombophilia. Administration of desmopressin (0.3-0.4 microgram/kg) produced a 4.0-fold increase in plasmin-alpha 2-plasmin inhibitor complex at 30 min, whereas neither FgDP nor FbDP was elevated significantly. These findings indicate that desmopressin infusion provokes the generation of plasmin in vivo, but most of the plasmin generated is complexed to alpha 2-plasmin inhibitor and does not degradate fibrin or fibrinogen.