Fibrin Lysis Research Articles

The effect of the liposomal form of alteplase on the effectiveness of thrombolysis in coronary arteries in acute myocardial infarction

A liposomal (Lip) formulation of tissue plasminogen activator, alteplase (AlT), has been developed. The quantitative and qualitative composition of the liposomes, as well as their physicochemical properties and proteolytic activity, have been studied in relation to the thrombolytic liposomal form. It was determined that a formulation consisting of liposomes with a phosphatidylcholine/cholesterol ratio of 1.5 : 1, and lipids/alteplase ratio of 1 : 1, is optimal for treating acute myocardial infarction (AMI) in experimental models. At different component ratios, liposomes had a negative zeta potential value greater than 30 mV, indicating their aggregative stability, even after storage for two days at 20 degrees Celsius. Liposomes derived from soy phosphatidylcholine showed greater colloidal stability with a zeta potential of approximately –57 mV and a lower hydrodynamic diameter of approximately 140 nanometers, compared to liposomes derived from egg phosphatidylcholine, which had a zeta potential around –35.4 mV and a hydrodynamic diameter around 220 nanometers. The initial content of free AlT in the liposome supernatant from egg phosphatidylcholine (Lipeg) was 15.0 ± 4.0 %. During the incubation period of 4 days, the concentration of free AlT decreased to 9.0 ± 4.5 %. In contrast, in liposomes derived from soy phosphatidylcholine (LipS), the content of free AlT increased from 11.0 ± 4.5 % to 32.5 ± 6.0 % over the same incubation period. The value of the proteolytic activity of tissue plasminogen activator (tPA) in the compositions of Lipeg(AlT) and Lips (AlT) depends on the type of phosphatidylcholine. The initial tPA activity in Lipeg (AlT) was 36.0 %, and after 1 day, it increased to 45 %. In Lips (AlT), the initial activity was 61.0 % and increased to 66 % after 1 day. When using the liposomal form of alteplase for delivery into the coronary arteries of rats with acute myocardial infarction (AMI), a more complete fibrin lysis is noted compared to animals receiving the native form of the drug. The developed system of targeted delivery of alteplase using soy liposomes has been shown to significantly improve the degree of coronary artery lumen restoration by more than 15 %, compared to the use of a conventional drug (p < 0.05).

Instant clot forming and antibacterial wound dressings: Achieving hemostasis in trauma injuries with S-nitroso-N-acetylpenicillamine-tranexamic acid-propolis formulation.

Wound infection and excessive blood loss are the two major challenges associated with trauma injuries that account for 10% of annual deaths in the United States. Nitric oxide (NO) is a gasotransmitter cell signaling molecule that plays a crucial role in the natural wound healing process due to its antibacterial, anti-inflammatory, cell proliferation, and tissue remodeling abilities. Tranexamic acid (TXA), a prothrombotic agent, has been used topically and systemically to control blood loss in reported cases of epistaxis and combat-related trauma injuries. Its properties could be incorporated in wound dressings to induce immediate clot formation, which is a key factor in controlling excessive blood loss. This study introduces a novel, instant clot-forming NO-releasing dressing, and fabricated using a strategic bi-layer configuration. The layer adjacent to the wound was designed with TXA suspended on a resinous bed of propolis, which is a natural bioadhesive possessing antibacterial and anti-inflammatory properties. The base layer, located furthest away from the wound, has an NO donor, S-nitroso-N-acetylpenicillamine (SNAP), embedded in a polymeric bed of Carbosil®, a copolymer of polycarbonate urethane and silicone. Propolis was integrated with a uniform layer of TXA in variable concentrations: 2.5, 5.0, and 7.5 vol % of propolis. This design of the TXA-SNAP-propolis (T-SP) wound dressing allows TXA to form a more stable clot by preventing the lysis of fibrin. The lactate dehydrogenase-based platelet adhesion assay showed an increase in fibrin activation with 7.5% T-SP as compared with control within the first 15 min of its application. A scanning electron microscope (SEM) confirmed the presence of a dense fibrin network stabilizing the clot for fabricated dressing. The antibacterial activity of NO and propolis resulted in a 98.9 ± 1% and 99.4 ± 1% reduction in the colony-forming unit of Staphylococcus aureus and multidrug-resistant Acinetobacter baumannii, respectively, which puts forward the fabricated dressing as an emergency first aid for traumatic injuries, preventing excessive blood loss and soil-borne infections.

Synergism of red blood cells and tranexamic acid in the inhibition of fibrinolysis

BackgroundPostpartum hemorrhage (PPH) is the leading cause of maternal death worldwide. The World Maternal Antifibrinolytic trial showed that antifibrinolytic tranexamic acid (TXA) reduces PPH deaths. Maternal anemia increases the risk of PPH. The World Maternal Antifibrinolytic-2 trial is now assessing whether TXA can prevent PPH in women with anemia. Low red blood cell (RBC) counts promote fibrinolysis by altering fibrin structure and plasminogen activation. ObjectivesWe explored interactions between RBCs and TXA in inhibiting fibrinolysis. MethodsWe used global fibrinolytic assays (ball sedimentation and viscoelasticity) to monitor the lysis of fibrin containing plasminogen and tissue-type plasminogen activator. We applied a fluorogenic kinetic assay to measure plasmin generation in fibrin clots and scanning electron microscopy to study fibrin structure. ResultsAccording to parallel-line bioassay analysis of the fibrin lysis-time data, the antifibrinolytic potency of 4-128 μM TXA was increased in the presence of 10% to 40% (v/v) RBCs. Global fibrinolysis assays showed that the joint effect of RBCs and TXA was about 15% larger than the sum of their individual effects in the inhibition of fibrinolysis. In plasminogen activation, TXA added the same increment of inhibition to the effect of RBCs at any cell count in the fibrin clot. Regarding fibrin structure, TXA thickened fibrin fibers, which impaired plasminogen activation, whereas RBCs promoted fine fibers that were more resistant to plasmin. ConclusionsThe antifibrinolytic potency of TXA is enhanced in fibrin formed in the presence of RBCs through inhibition of plasminogen activation and fibrin lysis, which correlates with modifications of fibrin structures.

DNA and histones impair the mechanical stability and lytic susceptibility of fibrin formed by staphylocoagulase.

Staphylocoagulase (SCG) is a virulence factor of Staphylococcus aureus, one of the most lethal pathogens of our times. The complex of SCG with prothrombin (SCG/ProT) can clot fibrinogen, and SCG/ProT-induced fibrin and plasma clots have been described to show decreased mechanical and lytic resistance, which may contribute to septic emboli from infected cardiac vegetations. At infection sites, neutrophils can release DNA and histones, as parts of neutrophil extracellular traps (NETs), which in turn favor thrombosis, inhibit fibrinolysis and strengthen clot structure. To characterize the combined effects of major NET-components (DNA, histone H1 and H3) on SCG/ProT-induced clot structure, mechanical and lytic stability. Recombinant SCG was used to clot purified fibrinogen and plasma. The kinetics of formation and lysis of fibrin and plasma clots containing H1 or core histones+/-DNA were followed by turbidimetry. Fibrin structure and mechanical stability were characterized with scanning electron microscopy, pressure-driven permeation, and oscillation rheometry. Histones and DNA favored the formation of thicker fibrin fibers and a more heterogeneous clot structure including high porosity with H1 histone, whereas low porosity with core histones and DNA. As opposed to previous observations with thrombin-induced clots, SCG/ProT-induced fibrin was not mechanically stabilized by histones. Similarly to thrombin-induced clots, the DNA-histone complexes prolonged fibrinolysis with tissue-type plasminogen activator (up to 2-fold). The anti-fibrinolytic effect of the DNA and DNA-H3 complex was observed in plasma clots too. Heparin (low molecular weight) accelerated the lysis of SCG/ProT-clots from plasma, even if DNA and histones were also present. In the interplay of NETs and fibrin formed by SCG, DNA and histones promote structural heterogeneity in the clots, and fail to stabilize them against mechanical stress. The DNA-histone complexes render the SCG-fibrin more resistant to lysis and thereby less prone to embolization.

Association of d-dimer levels with in-hospital outcomes among COVID-19 positive patients: a developing country multicenter retrospective cohort.

This multicenter retrospective study was carried out in two tertiary care hospitals in Karachi, Pakistan. The study included adult patients admitted with a laboratory-confirmed coronavirus disease 2019 infection, with at least one measured d-dimer within 24h following admission. Discharged patients were compared with the mortality group for survival analysis. The study population of 813 patients had 68.5% males, with a median age of 57.0 years and 14.0 days of illness. The largest d-dimer elevation was between 0.51-2.00mcg/ml (tertile 2) observed in 332 patients (40.8%), followed by 236 patients (29.2%) having values greater than 5.00mcg/ml (tertile 4). Within 45 days of hospital stay, 230 patients (28.3%) died, with the majority in the ICU (53.9%). On multivariable logistic regression between d-dimer and mortality, the unadjusted (Model 1) had a higher d-dimer category (tertile 3 and tertile 4) associated with a higher risk of death (OR: 2.15; 95% CI: 1.02-4.54, P=0.044) and (OR: 4.74; 95% CI: 2.38-9.46, P<0.001). Adjustment for age, sex, and BMI (Model 2) yields only tertile 4 being significant (OR: 4.27; 95% CI: 2.06-8.86, P<0.001). Higher d-dimer levels were independently associated with a high risk of mortality. The added value of d-dimer in risk stratifying patients for mortality was not affected by invasive ventilation, ICU stays, length of hospital stays, or comorbidities.

Persisting Endothelial Cell Activation and Hypercoagulability after Recovering from COVID-19: The Roadmap-Post COVID-19 Study

Background: In patients with severe COVID-19, activation of blood coagulation and endothelial cells orchestrated with complement activation and cytokine storm leads to disease worsening and death. Hypercoagulable state and endothelial cell activation and fibrinolytic unbalance are common alterations in patients with COVID-19 hospitalized either at the conventional medical ward or at the intensive care unit (ICU). Two systematic reviews highlight that D-dimer values are higher in non survivors as well as in patients with severe COVID-19 than in those with mild disease, showing the association between D-dimer levels and disease severity or death. Nevertheless, there are limited data in small series of patient, on the persistence of hypercoagulability and endothelial cell activation following recovery from COVID-19. Aims: To investigate the persistence of endothelial cell activation and hypercoagulability after recovery from COVID-19. Patients/Methods. COVID-19 survivors (n = 208) and 30 healthy individuals were enrolled in this study. Methods: In ,total, 208 COVID-19 survivors were included in the study; 125 males (60%) and 83 females (40%) with a median age of 50 years (IQR = 20, range 18 to 78 years). Biomarkers of hypercoagulability and endothelial cell activation: The procoagulant phospholipid-dependent clotting time (PPL-ct) was measured using a factor Xa-based clotting assay STA®-Procoag-PPL. Free-TFPI levels were measured with the ELISA Free TFPI, Asserachrom®; D-dimer and fibrin monomers (FM) were measured by STA Liatest D-Di and STA Liatest FM; soluble thrombomodulin (sTM) was measured by Asserachrom® TM. All assays were from Diagnostica Stago, Asnières, France. Heparanase-levels were measured with ELISA kits R&D. Systems (Lille France). Detection of anti-SARS-CoV2 antibodies: IgG and IgA anti-SARS-CoV-2 antibodies were detected in the sera of the survivors using a semi-quantitative commercial ELISA methodology (Euroimmun Medizinische Labordiagnostika AG, Lubeck, Germany) Results: The median interval between symptom onset and screening for SARS-CoV-2 antibodies was 62 days (IQR = 22 days). Antibodies against SARS-CoV-2 were detected in all survivors enrolled in the study. The median level of IgG and IgA antibodies was 5.68 U (IQR = 6.19) and 3.62 U (IQR = 5.36), respectively. In 112 survivors with known blood group, 48 (43%) were group O, 44 (39%) were group A, 14 (13%) were group B, and 6 (5.4%) were group AB. Survivors showed significantly higher levels of D-Dimers, FM, TFPI, and heparanase as compared to that of the control group. Survivors had significantly shorter PPL-ct . One out of four of COVID-19 survivors showed increase at least one biomarker of endothelial cell activation or hypercoagulability (Table1). Elevated D-dimer was associated with older age. Elevated FM was associated with female gender. Elevated heparanase was independently associated with male gender. Decreased Procoag-PPL clotting time was associated with female gender. Univariate and multivariate logistic regression analysis examining predictors of hypercoagulability in study cohort of COVID-19 survivors are reported in table 2 . The interval between COVID-19 diagnosis and assessment was not associated with the changes of the studied biomarkers. Conclusion: The ROADMAP-postCOVID-19 study offers an analysis of a large panel of biomarkers of endothelial cell activation and hypercoagulability in survivors of COVID-19. The study documents that two months after symptoms' onset, activation of endothelial cells, in vivo thrombin generation, and fibrin lysis are frequent phenomena up to two months from COVID-19 symptom onset. The data presented herein allow to propose that evaluation of blood hypercoagulability (using D-dimer for instance) and endothelial cell activation could offer the possibility of prompt identification of COVID-19 survivors at risk of post-COVID-19 vascular complications. The findings of the present study underline the need for a thorough evaluation of a potential correlation between the sustained hypercoagulability and endothelial cell activation with the symptomatology of long-COVID-19 to apply anticipated diagnostic and therapeutic strategies. The clinical relevance of the identified biomarkers of endothelial activation and hypercoagulability in the assessment of the risk of long COVID-19 must be investigated in a prospective study. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

A Novel Marine Pyran-Isoindolone Compound Enhances Fibrin Lysis Mediated by Single-Chain Urokinase-Type Plasminogen Activator.

Fungi fibrinolytic compound 1 (FGFC1) is a rare pyran-isoindolone derivative with fibrinolytic activity. The aim of this study was to further determine the effect of FGFC1 on fibrin clots lysis in vitro. We constructed a fibrinolytic system containing single-chain urokinase-type plasminogen activator (scu-PA) and plasminogen to measure the fibrinolytic activity of FGFC1 using the chromogenic substrate method. After FITC-fibrin was incubated with increasing concentrations of FGFC1, the changes in the fluorescence intensity and D-dimer in the lysate were measured using a fluorescence microplate reader. The fibrin clot structure induced by FGFC1 was observed and analyzed using a scanning electron microscope and laser confocal microscope. We found that the chromogenic reaction rate of the mixture system increased from (15.9 ± 1.51) × 10−3 min−1 in the control group to (29.7 ± 1.25) × 10−3 min−1 for 12.8 μM FGFC1(p < 0.01). FGFC1 also significantly increased the fluorescence intensity and d-dimer concentration in FITC fibrin lysate. Image analysis showed that FGFC1 significantly reduced the fiber density and increased the fiber diameter and the distance between protofibrils. These results show that FGFC1 can effectively promote fibrin lysis in vitro and may represent a novel candidate agent for thrombolytic therapy.

Structural control of fibrin bioactivity by mechanical deformation

Fibrin is the fibrous protein network that comprises blood clots; it is uniquely capable of bearing very large tensile strains (up to 200%) due to multiscale force accommodation mechanisms. Fibrin is also a biochemical scaffold for numerous enzymes and blood factors. The biomechanics and biochemistry of fibrin have been independently studied. However, comparatively little is known about how fibrin biomechanics and biochemistry are coupled: how does fibrin deformation influence its biochemistry? In this study, we show that mechanically induced protein structural changes in fibrin affect fibrin biochemistry. We find that tensile deformation of fibrin leads to molecular structural transitions of α-helices to β-sheets, which reduced binding of tissue plasminogen activator (tPA), an enzyme that initiates fibrin lysis. Moreover, binding of tPA and Thioflavin T, a commonly used β-sheet marker, were mutually exclusive, further demonstrating the mechano-chemical control of fibrin biochemistry. Finally, we demonstrate that structural changes in fibrin suppressed the biological activity of platelets on mechanically strained fibrin due to reduced αIIbβ3 integrin binding. Our work shows that mechanical strain regulates fibrin molecular structure and biological activity in an elegant mechano-chemical feedback loop, which possibly extends to other fibrous biopolymers.

Plasma D-dimer level in early and late-onset neonatal sepsis.

BACKGROUNDNeonatal sepsis is a life-threatening disease. Early diagnosis is essential, but no single marker of infection has been identified. Sepsis activates a coagulation cascade with simultaneous production of the D-dimers due to lysis of fibrin. D-dimer test reflects the activation of the coagulation system. AIMTo assess the D-dimer plasma level, elaborating its clinicopathological value in neonates with early-onset and late-onset neonatal sepsis. METHODSThe study was a prospective cross-sectional study that included ninety neonates; divided into three groups: Group I: Early-onset sepsis (EOS); Group II: Late-onset sepsis (LOS); and Group III: Control group. We diagnosed neonatal sepsis according to our protocol. C-reactive protein (CRP) and D-dimer assays were compared between EOS and LOS and correlated to the causative microbiological agents.RESULTSD-dimer was significantly higher in septic groups with a considerably higher number of cases with positive D-dimer. Neonates with LOS had substantially higher levels of D-dimer than EOS, with no significant differences in CRP. Neonates with LOS had a significantly longer hospitalization duration and higher gram-negative bacteriemia and mortality rates than EOS (P < 0.01). Gram-negative bacteria have the highest D-dimer levels (Acinetobacter, Klebsiella, and Pseudomonas) and CRP (Serratia, Klebsiella, and Pseudomonas); while gram-positive sepsis was associated with relatively lower levels. D-dimer had a significant negative correlation with hemoglobin level and platelet count; and a significant positive correlation with CRP, hospitalization duration, and mortality rates. The best-suggested cut-off point for D-dimer in neonatal sepsis was 0.75 mg/L, giving a sensitivity of 72.7% and specificity of 86.7%. The D-dimer assay has specificity and sensitivity comparable to CRP in the current study.CONCLUSIONThe current study revealed a significant diagnostic value for D-dimer in neonatal sepsis. D-dimer can be used as an adjunct to other sepsis markers to increase the sensitivity and specificity of diagnosing neonatal sepsis.

SERODIAGNOSIS OF EARLY NEONATAL SEPSIS IN EGYPTIAN NEONATES

Neonatal sepsis is a life-threatening disease. Early diagnosis is essential, but no single marker of infection has been identified. Sepsis activates a coagulation cascade with simultaneous production of the D-dimers due to lysis of fibrin. D-dimer test reflects the activation of the coagulation system.

Robust thrombolytic and anti-inflammatory action of a constitutively active ADAMTS13 variant in murine stroke models

AbstractAdvances in our understanding of ADAMTS13 structure, and the conformation changes required for full activity, have rejuvenated the possibility of its use as a thrombolytic therapy. We have tested a novel Ala1144Val ADAMTS13 variant (constitutively active [ca] ADAMTS13) that exhibits constitutive activity, characterized using in vitro assays of ADAMTS13 activity, and greatly enhanced thrombolytic activity in 2 murine models of ischemic stroke, the distal FeCl3 middle cerebral artery occlusion (MCAo) model and transient middle cerebral artery occlusion (tMCAO) with systemic inflammation and ischemia/reperfusion injury. The primary measure of efficacy in both models was restoration of regional cerebral blood flow (rCBF) to the MCA territory, which was determined using laser speckle contrast imaging. The caADAMTS13 variant exhibited a constitutively active conformation and a fivefold enhanced activity against fluorescence resonance energy transfer substrate von Willebrand factor 73 (FRETS-VWF73) compared with wild-type (wt) ADAMTS13. Moreover, caADAMTS13 inhibited VWF-mediated platelet capture at subphysiological concentrations and enhanced t-PA/plasmin lysis of fibrin(ogen), neither of which were observed with wtADAMTS13. Significant restoration of rCBF and reduced lesion volume was observed in animals treated with caADAMTS13. When administered 1 hour after FeCl3 MCAo, the caADAMTS13 variant significantly reduced residual VWF and fibrin deposits in the MCA, platelet aggregate formation, and neutrophil recruitment. When administered 4 hours after reperfusion in the tMCAo model, the caADAMTS13 variant induced a significant dissolution of platelet aggregates and a reduction in the resulting tissue hypoperfusion. The caADAMTS13 variant represents a potentially viable therapeutic option for the treatment of acute ischemic stroke, among other thrombotic indications, due to its enhanced in vitro and in vivo activities that result from its constitutively active conformation.

Improved Reactive Oxygen Species Generation by Chiral Co3O4 Supraparticles under Electromagnetic Fields

AbstractOne of the most common methods to treat thromboembolism is the use of thrombolytic drugs to activate fibrinolytic protease. The aim of this treatment was to initiate the lysis of fibrin; however, there are many side‐effects associated with this form of treatment. Herein, we fabricated chiral Co3O4 supraparticles (SPs) with a g‐factor of up to 0.02 at 550 nm and paramagnetic performance applied in the treatment of thromboembolism under an electromagnetic field (MF). In vitro experiments showed that d‐SPs degraded blood clot within 8 hours under MF. Compared to l‐SPs, d‐SPs exhibited much stronger thrombolytic ability and effectively enhanced the survival rate of thrombosis model mice more than 70 % in the 25 d of observation. The results of mechanism study showed that under MF, the level of reactive oxygen species (ROS) produced by d‐SPs were 1.5 times higher than that of l‐SPs, which might be attributed to the chiral‐induced spin selectivity effects.

Improved Reactive Oxygen Species Generation by Chiral Co3 O4 Supraparticles under Electromagnetic Fields.

One of the most common methods to treat thromboembolism is the use of thrombolytic drugs to activate fibrinolytic protease. The aim of this treatment was to initiate the lysis of fibrin; however, there are many side-effects associated with this form of treatment. Herein, we fabricated chiral Co3 O4 supraparticles (SPs) with a g-factor of up to 0.02 at 550 nm and paramagnetic performance applied in the treatment of thromboembolism under an electromagnetic field (MF). In vitro experiments showed that d-SPs degraded blood clot within 8 hours under MF. Compared to l-SPs, d-SPs exhibited much stronger thrombolytic ability and effectively enhanced the survival rate of thrombosis model mice more than 70 % in the 25 d of observation. The results of mechanism study showed that under MF, the level of reactive oxygen species (ROS) produced by d-SPs were 1.5 times higher than that of l-SPs, which might be attributed to the chiral-induced spin selectivity effects.

Size‐ and charge‐dependent modulation of the lytic susceptibility and mechanical stability of fibrin‐histone clots by heparin and polyphosphate variants

BackgroundNeutrophil extracellular traps (NETs) containing DNA and histones are expelled from neutrophils in infection and thrombosis. Heparins, anticoagulant polyanions, can neutralize histones with a potential therapeutic advantage in sepsis. Polyphosphates, procoagulant polyanions, are released by platelets and microorganisms. ObjectivesTo characterize the combined effects of NET components and polyanions on clot structure, mechanical properties and lytic susceptibility. MethodsScanning electron microscopy, pressure‐driven permeation, turbidimetry, and oscillation rheometry were used for the characterization of the structure, viscoelasticity, and kinetics of formation and lysis of fibrin and plasma clots containing histones+/‐DNA in combination with unfractionated heparin, its desulfated derivatives, low molecular weight heparin (LMWH), pentasaccharide, and polyphosphates of different sizes. ResultsHistones and DNA inhibited fibrin lysis by plasmin, but this behavior was not neutralized by negatively charged heparins or short polyphosphates. Rather, fibrin lysis was further inhibited by added polyanions. Histones inhibited plasma clot lysis by tissue plasminogen activator and the response to added heparin was size dependent. Unfractionated heparin, LMWH, and pentasaccharide had no effect, exacerbated, or reversed histone inhibition, respectively. Histones increased the mechanical strength of fibrin, which was exacerbated by smaller heparin and polyphosphate molecules. Histones increased fibrin diameter and pore size of fibrin clots and this effect was neutralized by all heparin variants but enhanced by polyphosphates. ConclusionsDespite their common polyanionic character, heparins and polyphosphates exert distinct effects on fibrin mechanical and fibrinolytic stability. Anti‐fibrinolytic effects of histones were more often enhanced by polyanions not counteracted. Careful selection of anti‐histone strategies is required if they are to be combined with thrombolytic therapy.

Measurement of plasma fibrinogen and D-dimer in a sample of Iraqi patients with solid malignant tumors

Background: Multifactor affect the pathogenesis of thrombosis in solid malignancy; however, a significant role is attributed to the cancer cells ability to interact with and activate the host hemostatic system. [1] &#x0D; Hemostasis is highly correlated to tumor growth, angiogenesis and metastasis, modulation of these pathways reflects interesting and promising treatment options in the future. [1]&#x0D; Most patients with cancer frequently suffer from chronic compensated DIC and have abnormal laboratory coagulation tests without clinical manifestations of thrombosis, which is a subclinical hypercoagulable state that can be detected by varying degrees of activation of blood clotting. The results of laboratory tests in these patients reflect continuous fibrin formation and lysis during the course of malignancy. [1]&#x0D; Aim of study: To study the effect of solid malignant tumors on blood coagulation via measurements of plasma fibrinogen and D-dimer.&#x0D; Subjects and methods: Thirty patients (9 males and 21 females) attending the oncology consultatory out-patient clinic at Baghdad Teaching Hospital/ Medical City were randomly selected and included in this study.&#x0D; These patients were newly diagnosed as having malignant solid tumors depending on histopathological reports from private and governmental sectors.&#x0D; All the laboratory tests were done at the hematology and biochemistry departments of Teaching Laboratories/ Medical City.&#x0D; Results: Plasma fibrinogen level was significantly higher in patients group rather than control group (3.863 ±0.706) Vs (2.497±0.457 g/L} respectively, (P-value 0.001).The mean value of factor VIII activity was {181% ±58.4)and (99.3% ±11.1)for patient and control groups respectively, the P-Value was significant ( &gt; 0.001 ).D-dimer was negative for all members of control group, for patients group ( 66.7 %) of them showed positive D-dimer and (33.3)were negative for D-dimer ,P-value was significant ( &gt;0.001 ). Conclusions: There was increase in plasma fibrinogen level and positive D-dimer in cancer patients compared to the control group reflecting subclinical thrombophilia and higher risk of VTE in patients with solid tumors due to activation of prothrombotic and fibrinolytic pathways by malignant cells which is vital for the use of primary prophylaxis by anticoagulants.

D-dimer, a predictor of outcome of acute pancreatitis

Introduction Defect in coagulation present even in the early stage of acute pancreatitis. D-dimer is a small protein particle generated during blood clot disintegration due to lysis of fibrin. It is an accurate indicator of lysis of fibrin, so has an association with the severity of pancreatic inflammation. The study was undertaken to know the utility of d-dimer to forecast organ failure or complications in acute pancreatitis. Methodology From June 2019 to Jan 2020, 50 patients of acute pancreatitis were enrolled in this prospective study. Patients were subjected to the d-dimer test within 24 hours after admission. The patients were split into two groups; with organ failure (complications) and without any complications. The result of the d-dimer test was correlated with these groups. Results 50 patients of acute pancreatitis were included in this study. Organ failure or local complications observed included impairment renal in 4 patients (16%), vasopressor requirement in 4(8%), pulmonary dysfunction in 5 (10%) and multiple organ failure syndrome (MODS) in 5 (10%). The sensitivity of d-dimer was 75% and specificity was 90%. Positive predictive value and negative predictive value of ddimer were 91%, 74% respectively. Conclusions D-dimer is an accurate and cost-effective test to predict organ failure or local complications in a patient of acute pancreatitis.

Orthognathic Surgery-Induced Fibrinolytic Shutdown Is Amplified by Tranexamic Acid

Little is known of the systemic effects of oral and maxillofacial surgery on the hemostatic balance, including the biochemical effects of tranexamic acid (TXA), on fibrin clot lysis. The present study investigated the effects of orthognathic surgery on fibrin lysis, fibrin structure, and D-dimer and evaluated the effect of TXA on these fibrinolytic measures. The present double-blind, controlled, and randomized, placebo study included patients referred to the Department of Oral and Maxillofacial Surgery at the University Hospital of Southern Denmark-Esbjerg from August 2014 through September 2016. The patients were elective and had a diagnosis of maxillary or mandibular deficiency, either excessive or asymmetric. All patients underwent bimaxillary orthognathic surgery (OS) with or without maxillary segmentation or additional genioplasty. The patients were blindly randomized to treatment with TXA or placebo. The primary predictor variable was OS. The secondary predictor variable was an intravenous dose of 1g of TXA or equivalent placebo preoperatively. Blood samples were collected before surgery and 5hours after the initiation of surgery. The primary outcome variable was lysis of fibrin. The fibrin structure properties and D-dimer were secondary outcome measures. The Mann-Whitney U test was used for the within-group comparisons. The Wilcoxon signed rank test was used for the between-group comparisons. The sample included 96 patients; 45 received placebo and 51 received TXA. Fibrin lysis decreased after OS (P<.001). The fibrinolytic shutdown decreased significantly more in the TXA group than in the placebo group (P<.001). OS altered the fibrin structure properties with comparable effects in the 2 groups. D-dimer increased postoperatively but significantly less so in the TXA group than in the control group (P<.001). OS is associated with fibrinolytic shutdown and alters fibrin structure properties, driving the hemostatic balance in a prothrombotic direction. The fibrinolytic shutdown is significantly amplified by TXA.

Structure, Mechanical, and Lytic Stability of Fibrin and Plasma Coagulum Generated by Staphylocoagulase From Staphylococcus aureus.

Staphylococcus aureus causes localized infections or invasive diseases (abscesses or endocarditis). One of its virulence factors is staphylocoagulase (SCG), which binds prothrombin to form a complex with thrombin-like proteolytic activity and leads to uncontrolled fibrin generation at sites of bacterial inoculation. The aim of this study was to characterize the formation, structure, mechanical properties and lysis of SCG-generated clots. Recombinant SCG was expressed in Escherichia coli, purified and the amidolytic activity of its complexes with human prothrombin (SCG-PT) and thrombin (SCG-T) was determined using human thrombin as a reference. Fibrin clots were prepared from purified fibrinogen and human plasma using thrombin, SCG-PT or SCG-T as a coagulase. The kinetics of clot formation and lysis by tissue-type plasminogen activator (tPA) were monitored with turbidimetric assays. Fibrin ultrastructure was examined with scanning electron microscopy and small-angle X-ray scattering (SAXS). Fibrin clot porosity was characterized with fluid permeation assays, whereas the viscoelastic properties and mechanical stability were evaluated with oscillation rheometry. Compared to thrombin, the amidolytic and clotting activity of SCG-PT was 1.6- to 2.5-fold lower on a molar basis. SCG-T had equivalent amidolytic, but reduced clotting activity both on pure fibrinogen (1.6-fold), and in plasma (1.3-fold). The SCG-PT and SCG-T generated fibrin with thicker fibers (10–60% increase in median diameter) than thrombin due to increased number of fibrin protofibrils per fiber cross-section. According to the fluid permeability of the clots SCG-PT and SCG-T promoted the formation of more porous structures. The shear stress resistance in the pure fibrin and plasma clots generated by SCG-PT was significantly lower than in the thrombin clots (243.8 ± 22.0 Pa shear stress was sufficient for disassembly of SCG-PT fibrin vs. 937.3 ± 65.6 Pa in thrombin clots). The tPA-mediated lysis of both pure fibrin and plasma clots produced by SCG-PT or SCG-T was accelerated compared to thrombin, resulting in up to a 2.1-fold increase in tPA potency. Our results indicate that SCG generates a thrombus scaffold with a structure characterized by impaired mechanical stability and increased lytic susceptibility. This proneness to clot disintegration could have implications in the septic embolism from endocardial bacterial vegetation.

The Effect of Hydrogen Sulfide on Different Parameters of Human Plasma in the Presence or Absence of Exogenous Reactive Oxygen Species.

The main aim of the study is to examine the effect of sodium hydrosulfide (NaHS), an H2S donor, on the oxidative stress in human plasma in vitro. It also examined the effects of very high concentrations of exogenous hydrogen sulfide on the hemostatic parameters (coagulation and fibrinolytic activity) of human plasma. Plasma was incubated for 5–30 min with different concentrations of NaHS from 0.01 to 10 mM. Following this, lipid peroxidation was measured as a thiobarbituric acid reactive substance (TBARS) concentration and the oxidation of amino acid residues in proteins was measured by determining the amounts of thiol groups and carbonyl groups. Hydrogen peroxide (H2O2) and the hydroxyl radical generating oxidation system (Fe/H2O2) were used as oxidative stress inducers. Hemostatic factors, such as the maximum velocity of clot formation, fibrin lysis half-time, the activated partial thromboplastin time (APTT), thrombin time (TT), and international normalized ratio (INR), were estimated. Changes in lipid peroxidation, carbonyl group formation, and thiol group oxidation were detected at high concentrations of H2S (0.1–10 mM), and these results indicate that NaHS (as the precursor of H2S) may have pro-oxidative effects in human plasma in vitro. Moreover, considering the data presented in this study, we suggest that the oxidative stress stimulated by NaHS (at high concentrations: 1–10 mM) is not involved in changes of the hemostatic activity of plasma.

Thrombin and plasmin generation in patients with plasminogen or plasminogen activator inhibitor type 1 deficiency.

IntroductionDeficiencies of plasminogen and plasminogen activator inhibitor type 1 (PAI‐1) are rare disorders of fibrinolysis. Current laboratory assays for analysis of activity of plasminogen and PAI‐1 do not provide an accurate correlation with clinical phenotype.MethodsThe Nijmegen Hemostasis Assay (NHA) was used to simultaneously measure thrombin and plasmin generation in 5 patients with plasminogen deficiency (PLGD) and 10 patients with complete PAI‐1 deficiency. Parameters analysed included: lag time ratio, thrombin peak time ratio, thrombin peak height, thrombin potential (AUC), fibrin lysis time, plasmin peak height and plasmin potential. Parameters were expressed as a percentage compared to a reference value of 53 healthy normal controls.ResultsPatients with PLGD demonstrated a short lag time and thrombin peak time, with normal thrombin peak height but an increased AUC. Plasmin generation was able to be detected in only one (23% plasminogen activity) of the five PLGD patients. All ten PAI‐1 deficient patients demonstrated a short lag and thrombin peak time, low thrombin peak height with normal AUC. Plasmin generation revealed an increased plasmin peak and plasmin potential; interestingly, there was a large variation between individual patients despite all patients having the same homozygous defect.ConclusionPatients with either PLGD or PAI‐1 deficiency show distinct abnormalities in plasmin and thrombin generation in the NHA. The differences observed in the propagation phase of thrombin generation may be explained by plasmin generation. These results suggest that disorders of fibrinolysis also influence coagulation and a global assay measuring both activities may better correlate with clinical outcome.