Disturbances of blood coagulation associated with Salmonella typhi infections

Disturbances of blood coagulation were studied in 32 consecutive patients with typhoid fever on their admission to hospital. Estimations of prothrombin time, activated partial thromboplastin time, fibrinogen, fibrin degradation products (FDPs), factors VII, VIII and XII, alpha I antitrypsin, plasminogen, CI esterase inhibitor, and platelet counts were performed as well as liver function tests and blood counts. Five patients had laboratory evidence of disseminated intravascular coagulation (DIC) and two had a generalised bleeding disorder which in the other three was inapparent. The platelet count in the group as a whole was low (P less than 0.05) and the FDPs in most cases were mildly elevated. The pre-kallikrein values were depressed in three of the five with DIC, whereas factor XII was not reduced. These results indicate that bleeding disorders in typhoid fever are uncommon. The depression of pre-kallikrein indicates that the DIC is probably triggered by activation of the intrinsic coagulation pathway. Most patients had lymphopenia and monocytopenia but only two had neutropenia.     

Effect of clofibrate on intravascular coagulation in hyperlipoproteinemia.

Intravascular coagulation (IVC) was evaluated in 19 patients with type II and 11 with type IV hyperlipoproteinemia before and after clofibrate therapy by measurements of soluble fibrin complexes (SFC) in plasma; fibrinolysis was estimated by quantitation of fibrin (ogen) degradation products in serum. Untreated type II and type IV patients had increased SFC (P less than 0.01). The former also had activation of the intrinsic coagulation pathway as evidenced by decreased plasma prekallikrein (P less than 0.001), kallikrein inhibitors (P less than 0.001), and factor XII (P less than 0.02). Although clofibrate treatment of the type II patients did not change plasma lipids, it decreased intravascular coagulation, apparently via decreased factor XII activation and stimulation of fibrinolysis. In contrast, treated type IV patients had unchanged SFC and FDP levels, despite decreased plasma triglycerides (P less than 0.01). Clofibrate-induced changes in blood coagulation are independent of lipid-lowering. Clofibrate therapy decreases intravascular coagulation in type II patients and may help to prevent thromboembolic sequelae.     

Coagulation, fibrinolytic, and inhibitory proteins in acute myocardial infarction and angina pectoris.

BACKGROUND AND METHOD: The role of thrombus formation in the pathogenesis of acute myocardial infarction (AMI) and unstable angina pectoris has been well established. However, comprehensive and systematic studies of the blood coagulation, fibrinolytic, and inhibitory proteins are not available in patients with these conditions. Fourteen patients with AMI, 10 patients with angina pectoris, and 32 normal volunteers were studied. Plasma antigen concentrations and/or activities of high-molecular-weight kininogen (HMWK), fibrinogen, fibronectin, plasminogen, D-dimer, tissue plasminogen activator (t-PA), alpha 2-antiplasmin, alpha 2-macroglobulin, alpha 1-antitrypsin, protein C, total and free protein S, antithrombin III (AT-III), von Willebrand factor (vWF), factors (F) XII, XI, IX, VIII, VII, X, V, II, and XIII, and plasma antiplasmin activity were measured using appropriate functional or immunologic assays. RESULTS: The AMI group showed a significant reduction in F XII activity, F XII activity-to-concentration ratio, and HMWK concentration. In addition, the AMI patients exhibited a significant elevation of plasma F XI activity, F IX concentration, and F IX activity, and vWF, fibrinogen, D-dimer, and t-PA concentrations. This was associated with significant reductions in F V, F II, and AT-III activity-to-concentration ratio. Many of the changes observed in AMI patients were also present in patients with angina pectoris. Furthermore, the latter group exhibited an elevation of F VIII activity, alpha 2-macroglobulin activity, and alpha 1-antitrypsin concentration and a significant reduction of antiplasmin activity despite a normal alpha 2-antiplasmin concentration. CONCLUSIONS: The observed reduction of the plasma F XII activity-to-antigen concentration ratio combined with a reduced HMWK concentration suggests intrinsic pathway activation, while the elevation of the D-dimer concentration indicates thrombin generation and fibrin formation and degradation in the AMI group. The latter changes were also present in patients with angina pectoris. Both AMI and angina groups showed several other abnormalities of the coagulation, fibrinolytic, and inhibitory systems. The results suggest the presence of a prothrombotic state associated with the activation of coagulation and fibrinolytic systems in patients with acute myocardial ischemia or infarction.     

Plasma Constituents Other Than Low-Density Lipoprotein Adsorbed by Dextran-Sulfate Column

Abstract: The dextran-sulfate cellulose (DSC) column used for low-density lipoprotein (LDL) apheresis adsorbs plasma constituents other than LDL that have the following characteristics: proteins containing apolipoprotein B, proteins involved in the initial contact phase of the intrinsic coagulation pathway (coagulation factor XII, high molecular weight kininogen and prekallikrein), factors with lipophilic characteristics (coagulation factor VII, VIII, and vitamin E), and proteins with adhesive or other characters (von Willebrand factor, fibronectin, and serum amyloid P components). Adsorption of these proteins seems to serve in the prevention or regression of atherosclerosis. Moreover, plasma treatment by the DSC column may be useful for treatment of such inexorable diseases as amyloidosis. On the other hand, the column generates bradykinin by activation of the initial contact phase of the intrinsic coagulation pathway. Bradykinin generation may explain hypotension during LDL apheresis observed in patients taking angiotensin converting enzyme (ACE) inhibitors.     

Identifying hypocoagulable states with a modified global assay of overall haemostasis potential in plasma.

To test the sensitivity of the global assay of overall haemostasis potential (OHP) in detecting hypocoagulation, the OHP was assayed in plasma containing exogenous thrombin (0.04 IU/ml), tissue-plasminogen activator (330 ng/ml), Ca and a platelet reagent. Commercial plasmas with factor II, V, VIII, IX, X, XI, XII or VII deficiency were mixed with normal plasma in different proportions to imitate different severities. Samples from patients with haemophilia and factor XII deficiency were also examined. No clot was found in the absence of factor II/factor X, indicating that the tiny dose of thrombin worked solely as a trigger for the intrinsic pathway activation. Changed levels of the investigated coagulants, apart from factor XII, influenced the outcome. OHPs were decreased in patients with haemophilia but were unchanged or even increased in those with factor XII deficiency. This modified OHP method may therefore be useful for estimating the bleeding tendency in haemophilic patients and to find suitable doses and intervals for prophylactic treatment. It may also be of use in investigations of the effect of antifibrinolytic drugs as well as for identifying a thrombotic tendency in patients with factor XII deficiency. For detection of other coagulation factor deficiencies, our investigations with the commercial plasmas suggest that the OHP assay is also valuable, especially when the intrinsic pathway of the coagulation cascade is impaired.     

The Effects of Collagen and Kaolin on the Intrinsic Coagulant Activity of Platelets. EVIDENCE FOR AN ALTERNATIVE PATHWAY IN INTRINSIC COAGULATION NOT REQUIRING FACTOR XII

Collagen and kaolin have been shown by other workers to initiate intrinsic coagulation by activating factor XII in plasma and to have complex effects on platelets. Because of the presence of collagen at sites of vascular injury there is good reason to believe that collagen has physiological importance in haemostasis. The present experiments were done to determine the effects of collagen and kaolin on platelets and to distinguish the platelet effects from the activity which these surface-active agents produce in plasma.
Using an albumin-density-gradient separation (ADGS) method for washing platelets free of loosely adsorbed coagulation factors, it is shown here that collagen can induce a coagulant activity in platelets which initiates intrinsic coagulation. This activity is independent of factor XII, provided factor XI is present. It is postulated that this collagen-induced coagulant activity of platelets provides an alternative pathway, by-passing factor-XII activation, for initiating intrinsic coagulation. The existence of this alternative pathway may provide an explanation for the absence of a haemostatic defect in Hageman trait. The effects of kaolin were similar to those of collagen, but kaolin had greater capacity to activate plasma factor XII and platelet factor 3 and relatively less capacity to activate platelet-associated factor XI.     

Concomitant occurrence of disseminated intravascular coagulation and factor VIII inhibitor in a patient with prostatic cancer

An 86-year-old man, diagnosed as having carcinoma of the prostate, stage D, was admitted to the hospital. Soon after admission, he developed bleeding from various sites, including intravenous puncture sites and gastrointestinal and urinary tracts. A clinical diagnosis of disseminated intravascular coagulation (DIC) was made, which was corroborated by laboratory data. A factor VIII inhibitor of 12.5 Bethesda units was also identified in the patient's plasma. Concomitant occurrence of disseminated intravascular coagulation and an acquired factor VIII inhibitor has not been reported previously.     

Influence of coagulation factors on intrinsic thrombin generation.

The intrinsic coagulation activity assay (INCA) is a new thrombin-generation test that imitates the intrinsic pathway of blood coagulation. The aim of the present study was to investigate the influence of the main coagulation factors on the INCA. The INCA was performed with citrated plasma samples supplemented with different amounts of fibrinogen. The INCA and activated partial thromboplastin time determination were performed with factor-depleted plasmas and with mixtures of depleted plasmas with normal plasma. Supplemented purified fibrinogen resulted in a decrease of intrinsic thrombin generation (50% inhibitory concentration = 0.8 g/l). The INCA depends on the intrinsic factors (factors VIII, IX, XI and XII) and on the factors of the common pathway (factors II, V and X): for normal thrombin generation, at least about 50% of normal factor II is necessary. For the majority of factors, the sensitivity of the INCA appears to be approximately one order of magnitude better than that of the activated partial thromboplastin time. The INCA allows one to diagnose defects in the intrinsic coagulation system and might be a useful test to support development and characterization of new drugs targeted at the intrinsic generation of thrombin.     

IgM Inhibitors of the Contact Activation Phase of Coagulation in Chlorpromazine- Treated Patients

S ummary . In this report we have described three patients with chronic schizophrenia on long-term chlorpromazine therapy who developed asymptomatic IgM inhibitors of the intrinsic phase of blood coagulation. The anticoagulant resulted in decreased measurements of all of the plasma clotting factors in the intrinsic pathway (factors VIII, IX, XI, XII, Fletcher factor and Fitzgerald factor). Using crude coagulation reagents, the serum of these patients interfered with the clot promoting activity of contact product. To determine the relationship between drug therapy and these IgM inhibitors, we have studied nine additional schizophrenic patients on long-term chlorpromazine therapy. All nine chlorpromazine-treated patients had significantly increased levels of serum IgM and asymptomatic inhibitors of coagulation. We conclude that long-term high-dose chlorpromazine treatment of schizophrenic patients results in an increased concentration of IgM which has inhibitory activity in the contact phase of blood coagulation.     

Low‐Density Lipoprotein Apheresis and Changes in Plasma Components

Abstract: Several different techniques of low‐density lipoprotein (LDL) apheresis are available for management of severe hypercholesterolemia. Among them, the adsorption system with a dextran‐sulfate cellulose (DSC) column is most widely used. In addition to adsorption of LDL, DSC adsorbs plasma constituents that have the following characteristics: proteins containing apolipoprotein B (Lp[a]); proteins involved in the initial contact phase of the intrinsic coagulation pathway (coagulation factor XII, high‐molecular‐weight kininogen and prekallikrein); factors with lipophilic characteristics (coagulation factor VII, coagulation factor VIII, and vitamin E); and proteins with adhesive or other characteristics (von Willebrand factor, fibronectin, serum amyloid P component, hepatocyte growth factor). The adsorption of these proteins seems to ameliorate prevention or regression of atherosclerosis. Moreover, plasma treatment by the DSC column may be useful for treatment of inexorable diseases, such as amyloidosis. On the other hand, the DSC column generates bradykinin by activation of the initial contact phase of the intrinsic coagulation pathway. Bradykinin generation may explain the functional improvement in the circulatory system, as well as hypotension during LDL apheresis, which is observed in patients taking ACE inhibitors.     

Platelet coagulation-protein interactions

The biochemical mechanisms by which activated platelets participate in exposing receptors for the assembly of enzyme-cofactor-substrate complexes at all stages of the blood coagulation cascade are reviewed. Information derived from studies conducted during the last 30 years supports the concept that the initiation of blood coagulation is triggered by exposure of tissue factor at injury sites, leading to the generation of minute quantities of thrombin (limited by tissue factor pathway inhibitor), sufficient to activate platelets, factors XI, VIII, and V, and trigger the consolidation pathway (i.e., the sequential activation of factors XI, IX, X, and prothrombin on the activated platelet surface), leading to the generation of sufficient thrombin to convert fibrinogen to fibrin and effect hemostasis. Platelets localize coagulation to the hemostatic thrombus and protect coagulation enzymes from inhibition by both plasma and platelet inhibitors (e.g., protease nexin 2), thus preventing disseminated intravascular coagulation.     

Screening coagulation tests and clotting factors in homozygous beta-thalassemia.

In 30 children with homozygous beta-thalassemia the hemostasis screening tests (bleeding time, PT, PTT), platelet count and specific assays of clotting factors were carried out 25 days after their last transfusion. PT, PTT, and bleeding time showed minor variations; considerable thrombocytosis was found in splenectomized patients. Factors IX and XII were decreased in a high proportion of patients, the vitamin K-dependent factors (II, VII, IX, X) were slightly reduced and factors I, V and VIII remained within the normal range in a majority of patients. Hepatic failure resulting in defective protein synthesis does not explain the more marked impairment of factors XI and XII, which might be secondary to activation of the intrinsic coagulation and/or kallikrein systems following intravascular haemolysis and multiple blood transfusions.     

Activation of factor XI in plasma is dependent on factor XII [see comments]

The activation of factor XI initiates the intrinsic coagulation pathway. Until recently it was believed that the main activator of factor XI is factor XIIa in conjunction with the cofactor high molecular weight kininogen on a negatively charged surface. Two recent reports have presented evidence that in a purified system factor XI is activatable by thrombin together with the soluble polyanion dextran sulfate. To assess the physiological relevance of these findings we studied the activation of factor XI in normal and factor XII-deficient plasma. We used either kaolin/cephalin or dextran sulfate as a surface for the intrinsic coagulation pathway, tissue factor to generate thrombin via the extrinsic pathway, or the addition of alpha-thrombin directly. 125I-factor XI, added to factor XI-deficient plasma at physiologic concentrations (35 nmol/L), is rapidly cleaved on incubation with kaolin. The kinetics appear to be exponential with half the maximum cleavage at 5 minutes. Similar kinetics of factor XI cleavage are seen when 40 nmol/L factor XIIa (equal to 10% of factor XII activation) is added to factor XII-deficient plasma if an activating surface is provided. Tissue factor (1:500) added to plasma did not induce cleavage of factor XI during a 90-minute incubation, although fibrin formation within 30 seconds indicated that thrombin was generated via the extrinsic pathway. Adding 1 mumol/L alpha-thrombin (equivalent to 50% prothrombin activation) directly to factor XII deficient or normal plasma (with or without kaolin/cephalin/Ca2+ or dextran sulfate) led to instantaneous fibrinogen cleavage, but again no cleavage of factor XI was observable. We conclude that in plasma surroundings factor XI is not activated by thrombin, and that proposals of thrombin initiation of the intrinsic coagulation cascade are not supportable.     

Activation of the antihemophilic globulin A (factor VIII). 2. Effect of ampholine on the course of blood coagulation and the molecular conformation of factor VIII

Ampholine leads to an increase of activity of factor VIII and in vitro at the same time inhibits the activation of factor XII. The influence on factor XII takes place via influence on the contact surface. All the other coagulation factors remain uninfluenced. There are no differences between normal plasma and plasma of haemophilia with regard to the influence by ampholine. The molecular weight of factor VIII remains uninfluenced by ampholine. The activity of the various molecular forms of factor VIII is increased at the same level by ampholine.     

Stability of coagulation factors in thawed, solvent/detergent-treated plasma during storage at 4 degrees C for 6 days

BACKGROUND AND OBJECTIVES: Transfusion of fresh-frozen plasma is still a pillar in emergency medicine for using to prevent dilutional coagulopathy or disseminated intravascular coagulation after severe blood loss, but thawing procedures can delay its availability. On the other hand, the wastage of plasma, once thawed and not transfused within a defined time-period, represents an inefficient handling of economic resources and is contradictory to blood donor intentions. In this study we investigated the stability of coagulation factor activities and plasma protein levels during 6 days of storage of thawed solvent/detergent (S/D)-treated plasma at +4 degrees C. Our results may form the basis for reconsideration of expiry times of thawed S/D-treated plasma. MATERIALS AND METHODS: Five units of S/D-treated plasma (Octaplas) were thawed and warmed to 20 degrees C, then recooled and stored at +4 degrees C for 6 days. The activities of coagulation factors II, V, VII, VIII, IX, X, XI and XII, fibrinogen, antithrombin (AT), protein C, protein S and von Willebrand factor antigen (vWF:Ag) were measured on days 0, 1, 2, 3 and 6. RESULTS: Except for protein S, the activities of all coagulation factors and inhibitors were at least 0.5 U/ml during storage at 4 degrees C for 6 days. The mean levels, during storage, of factors IX, X, XI and XII, vWF:Ag, fibrinogen and protein C were at least 94%, and of factors II, V and VIII, and AT at least 78%, of the levels immediately after thawing; the activity of factor VII decreased to 83% and of protein S to 43% of the baseline values. CONCLUSIONS: Thawed S/D-treated plasma stored at +4 degrees C for up to 6 days still contains sufficient coagulation activities and plasma proteins to be regarded as suitable for transfusion in the established indications.     

Hageman Factor Activation in the Generalized Shwartzman Reaction Induced by Endotoxin

S ummary . The role of Hageman factor (factor XII) in triggering intravascular coagulation was studied in rabbits injected with Thorotrast and endotoxin. Besides changes of coagulation, parameters characteristic of consumption coagulopathy (e.g. decreases in platelet counts and fibrinogen levels), a drop in Hageman factor activity was observed. However, this decrease in Hageman factor activity does not appear responsible for triggering intravascular coagulation, becuase it was found that: (1) A decrease in Hageman factor activity occurred only in those animals which developed a generalized Shwartzman reaction with a drop in fibrinogen levels. A small single dose of endotoxin did not lower Hageman factor activity. (2) Coumarin pretreatment prevented the drop in Hageman factor activity after Thorotrast and endotoxin injections, although this would not be expected if Hageman factor was the first coagulation factor to be activated. (3) Inhibition of Hageman factor activation by lysozyme infusion did not prevent the generalized Shwartzman reaction elicited by Thorotrast and endotoxin.
We conclude that endotoxin triggers intravascular coagulation by a mechanism different from that of the intrinsic pathway of coagulation.     

Inhibition of platelet prothrombinase activity by a lupus anticoagulant

Lupus anticoagulants are spontaneously occurring antibodies with specificity for negatively charged phospholipids. The plasma of a patient with such a polyclonal antibody of IgM type demonstrated low levels of factor VIII coagulant activity (VIII:C) and factors IX, XI and XII when analyzed by biologic clotting assays, whereas in immunochemical assays, normal levels of VIII coagulant antigen and factor IX were obtained. After immunoadsorption of patient plasma with anti-IgM Sepharose, normal biologic activities were demonstrated in clotting assays for VIII:C, factors IX, XI, and XII. The addition of the patient's isolated IgM to normal plasma resulted in grossly abnormal results in these coagulation assays, and a pattern similar to that of the patient's plasma was obtained. The inhibitory effect of the patient's lupus anticoagulant on blood coagulation was demonstrated also in platelet-rich plasma. The results of the clotting assays indicated that the anticoagulant inhibited several of the reactions in the blood coagulation cascade. The availability of purified components made it possible to demonstrate an inhibiting effect on the activation of prothrombin by factor Xa in the presence of isolated platelets, as well as in a system where purified factor V and well defined phospholipid vesicles were substituted for the platelets.     

Tissue factor in trauma and organ dysfunction

Tissue factor (TF) performs an essential role in the blood clotting system by activating the extrinsic coagulation pathway following vascular injury. In addition to this physiological hemostatic role for wound repair, TF also plays pivotal roles in organ dysfunction in trauma patients by triggering pathological disseminated thrombosis and inflammation. Constitutively expressed TF in subendothelial cells is released into the circulation following trauma and can be detected as slightly elevated TF levels in the plasma. Liberation of constitutive TF into the blood and inducible tissue factor expression on monocytes and the other cells may synergistically increase plasma TF levels to higher values at the early stage of posttrauma, especially in patients with disseminated intravascular coagulation (DIC) in association with sustained systemic inflammatory response syndrome. Marked TF generation not adequately balanced by physiological coagulation inhibitors such as tissue factor pathway inhibitor in posttrauma DIC patients has been observed. Based on these pieces of evidence, it has now been accepted that combined activation of TF-dependent coagulation inadequately regulated by anticoagulant mechanisms and inflammation may synergistically play important roles in the pathogenesis of posttrauma multiple organ dysfunction syndrome.     

Importance of factor-IX-dependent prothrombinase formation--the Josso pathway--in clotting plasma

We report a study on the importance of factor IX activation in thromboplastin-dependent coagulation in plasma. Diluted, CaCl2-containing thromboplastin solutions at constant phospholipid concentration were used to trigger the coagulation in plasma from patients with congenital factor IX and factor VIII deficiency in the presence and absence of added factors IX and VIII, and the generation of thrombin activity was monitored. When coagulation is triggered with the high thromboplastin concentrations normally used in clinical routine tests, the generation of thrombin activity in plasma of patients with congenital factor IX deficiency before and after reconstitution with purified factor IX appears identical. When, however, coagulation is triggered with low thromboplastin concentrations, a clear dependency of the generation of thrombin activity on the concentration of factor IX becomes evident at factor IX concentrations lower than 30 nM (about 40% clotting factor activity). Factor VIII is a compulsory cofactor for this factor IX activity because the prothrombinase activity at optimal factor IX concentration is still critically dependent upon the amount of factor VIII present. The lower the amount of thromboplastin, the higher the importance of factor IX and factor VIII activation in thromboplastin-dependent coagulation. This suggests a role of this pathway in pathophysiological thrombin formation.     

Inhibition of factor XI activation attenuates inflammation and coagulopathy while improving the survival of mouse polymicrobial sepsis

Severe bacterial sepsis often leads to a systemic procoagulant and proinflammatory condition that can manifest as disseminated intravascular coagulation, septic shock, and multiple organ failure. Because activation of the contact proteases factor XII (FXII), prekallikrein, and factor XI (FXI) can trigger coagulation and inflammatory responses, the contact factors have been considered potential targets for the treatment of sepsis. However, the pathogenic role of contact activation in severe infections has not been well defined. We therefore investigated whether an anticoagulant antibody (14E11) that selectively inhibits prothrombotic FXI activation by activated FXII (FXIIa) modifies the course of bowel perforation-induced peritoneal sepsis in mice. Early anticoagulation with 14E11 suppressed systemic thrombin- antithrombin complex formation, IL-6, and TNF-α levels, and reduced platelet consumption in the circulation and deposition in the blood vessels. Treatment with 14E11 within 12 hours after bowel perforation significantly improved survival compared with vehicle treatment, and the saturating dose did not increase tail bleeding. These data suggest that severe polymicrobial abdominal infection induces prothrombotic FXI activation, to the detriment of the host. Systemic anticoagulation by inhibiting FXI activation or FXIIa procoagulant activity during sepsis may therefore limit the development of disseminated intravascular coagulation without increasing bleeding risks.