Explore the vast range of titles available.

During inflammation and situations of cellular stress protein disulfide isomerase (PDI) is released in the blood plasma from the platelet and endothelial cells to influence thrombosis. The addition of exogenous PDI makes the environment pro-thrombotic by inducing disulfide bond formation in specific plasma protein targets like vitronectin, factor V, and factor XI. However, the mechanistic details of PDI interaction with its target remain largely unknown. A decrease in the coagulation time was detected in activated partial thromboplastin time (APTT), prothrombin time (PT), and thrombin time (TT) on addition of the purified recombinant PDI (175 nM). The coagulation time can be controlled using an activator (quercetin penta sulfate, QPS) or an inhibitor (quercetin 3-rutinoside, Q3R) of PDI activity. Likewise, the PDI variants that increase the PDI activity (H399R) decrease, and the variant with low activity (C53A) increases the blood coagulation time. An SDS-PAGE and Western blot analysis showed that the PDI does not form a stable complex with either thrombin or antithrombin (ATIII) but it uses the ATIII–thrombin complex as a template to bind and maintain its activity. A complete inhibition of thrombin activity on the formation of ATIII–thrombin–PDI complex, and the complex-bound PDI-catalyzed disulfide bond formation of the target proteins may control the pro- and anti-thrombotic role of PDI.

Antithrombin, a major endogenous anticoagulant, is a serine protease inhibitor (serpin). We characterized the biological and clinical impact of variants involving C-terminal antithrombin. We performed comprehensive molecular, cellular, and clinical characterization of patients with C-terminal antithrombin variants from a cohort of 444 unrelated individuals with confirmed antithrombin deficiency. We identified 17 patients carrying 12 C-terminal variants, 5 of whom had the p.Arg445Serfs*17 deletion. Five missense variants caused qualitative deficiency, and 7, including 4 insertion-deletion variants, induced severe quantitative deficiency, particularly p.Arg445Serfs*17 (antithrombin <40%). This +1 frameshift variant had a molecular size similar to that of WT antithrombin but possessed a different C-terminus. Morphologic and cotransfection experiments showed that recombinant p.Arg445Serfs*17 was retained at the endoplasmic reticulum and had a dominant-negative effect on WT antithrombin. Characterization of different 1+ frameshift, aberrant C-terminal variants revealed that protein secretion was determined by frameshift site. The introduction of Pro441 in the aberrant C-terminus, shared by 5 efficiently secreted variants, partially rescued p.Arg445Serfs*17 secretion. C-terminal antithrombin mutants have notable heterogeneity, related to variant type and localization. Aberrant C-terminal variants caused by 1+ frameshift, with similar size as WT antithrombin, may be secreted or not, depending on frameshift site. The severe clinical phenotypes of these genetic changes are consistent with their dominant-negative effects.

Thrombophilias are usually caused by loss-of-function mutations in natural anticoagulants or gain-of-function mutations in procoagulants. A mutation in a Japanese family documents a novel mechanism, procoagulant (prothrombin) resistance to anticoagulant (antithrombin). Patients with hereditary thrombophilia often present with unusual clinical episodes of venous thrombosis at a young age and recurrence in atypical vessels, often with a family history of the condition. 1 Genetic studies of hereditary thrombophilia have revealed two types of genetic defects: loss-of-function mutations in the natural anticoagulants antithrombin, protein C, and protein S, along with gain-of-function mutations in procoagulant factors V (factor V Leiden) and II (prothrombin G20210A). 2 To date, numerous genetic defects have been found in families with hereditary thrombophilia, but there may be many undiscovered causative mutations. 3 Here, we describe a case of hereditary thrombosis induced by . . .

Antithrombin III, encoded by SerpinC1, is a major anti-coagulation molecule in vivo and has anti-inflammatory effects. We found that patients with low antithrombin III activities presented a higher risk of developing acute kidney injury after cardiac surgery. To study this further, we generated SerpinC1 heterozygous knockout rats and followed the development of acute kidney injury in a model of modest renal ischemia/reperfusion injury. Renal injury, assessed by serum creatinine and renal tubular injury scores after 24 h of reperfusion, was significantly exacerbated in SerpinC1+/− rats compared to wild-type littermates. Concomitantly, renal oxidative stress, tubular apoptosis, and macrophage infiltration following this injury were significantly aggravated in SerpinC1+/− rats. However, significant thrombosis was not found in the kidneys of any group of rats. Antithrombin III is reported to stimulate the production of prostaglandin I2, a known regulator of renal cortical blood flow, in addition to having anti-inflammatory effects and to protect against renal failure. Prostaglandin F1α, an assayable metabolite of prostaglandin I2, was increased in the kidneys of the wild-type rats at 3 h after reperfusion. The increase of prostaglandin F1α was significantly blunted in SerpinC1+/− rats, which preceded increased tubular injury and oxidative stress. Thus, our study found a novel role of SerpinC1 insufficiency in increasing the severity of renal ischemia/reperfusion injury.

Introduction We identified a novel variant of the antithrombin (AT) gene ( SERPINC1 ), c.96 T>G, p.Cys32Trp (C32W), located at the signal peptide cleavage site in a patient with congenital AT deficiency. The impact of signal peptide variants on the intracellular trafficking and secretion of AT proteins has not been previously studied. Thus, we analyzed the intracellular dynamics and signal peptide cleavage of the C32W variant of AT (AT-C32W). Materials and methods Wild-type AT (AT-WT) and AT-C32W expression vectors were transfected into HEK293 cells. Functional analyses were performed using western blotting and proteasome inhibition experiments. Signal peptide cleavage was evaluated by peptide sequencing. Results The AT antigen levels in the cell lysates and culture supernatants of the AT-C32W were reduced to 3.8% and 4.8%, respectively. Following proteasome inhibition, the AT-C32W level increased to 71.5% of that for AT-WT. Peptide sequencing identified a fragment corresponding to the N-terminal end of the signal peptide exclusively in AT-C32W. Discussion These results suggest that the signal peptide of AT-C32W is not cleaved properly, which causes intracellular degradation of AT-C32W by proteasomes that results in type I AT deficiency. Further studies on the intracellular dynamics of such variants may clarify the mechanisms underlying AT deficiency.

Coagulation balance is maintained through fine-tuned interactions among clotting factors, whose physiological concentrations vary substantially. In particular, the concentrations of coagulation proteases (pM to nM) are much lower than their natural inactivator antithrombin (AT, ~ 3 μM), suggesting the existence of other coordinators. In the current study, we found that transferrin (normal plasma concentration ~40 μM) interacts with fibrinogen, thrombin, factor XIIa (FXIIa), and AT with different affinity to maintain coagulation balance. Normally, transferrin is sequestered by binding with fibrinogen (normal plasma concentration ~10 μM) at a molar ratio of 4:1. In atherosclerosis, abnormally up-regulated transferrin interacts with and potentiates thrombin/FXIIa and blocks AT’s inactivation effect on coagulation proteases by binding to AT, thus inducing hypercoagulability. In the mouse model, transferrin overexpression aggravated atherosclerosis, whereas transferrin inhibition via shRNA knockdown or treatment with anti-transferrin antibody or designed peptides interfering with transferrin-thrombin/FXIIa interactions alleviated atherosclerosis. Collectively, these findings identify that transferrin is an important clotting regulator and an adjuster in the maintenance of coagulation balance and modifies the coagulation cascade.

Objective Exploring the effectiveness of visually managed health education in reducing the risk of venous thromboembolism in patients with complete occlusion of chronic coronary arteries. Methods In this study, 100 patients with chronic total occlusion of coronary arteries and undergoing percutaneous coronary intervention (PCI) in cardiovascular medicine were included and divided into a test group and a control group with 50 patients in each group. Patients in the test group received health education based on visualization management, while patients in the control group received conventional health education. Relevant data were collected for further comparison. Statistical analysis was performed using SPSS and t-test and χ 2 test were used to analyze the differences. Results After intervention, there were higher levels of antithrombin III (AT3) and activated partial prothrombin time (APTT), while lower levels of D-dimer (D-D), fibrinogen degradation product (FDP), fibrinogen (FBG), and thrombin time (TT) in the test group than those before intervention. The control group showed decreased AT3 and APTT, while increased D-D, FDP,TT and FBG levels ( P  < 0.05). After intervention, the levels of AT3 and APTT in the test group were higher than those in the control group, while the levels of D-D, FDP, FBG, and TT were lower than those in the latter control group ( P  < 0.05). Furthermore, both groups of patients showed a decrease in Padua scores and an increase in prevention cognition scores after intervention ( P  < 0.05). After intervention, the Padua score of the test group was lower than that of the control group ( P  < 0.05). The test group had higher compliance score ( P  < 0.001) and satisfaction ( P  < 0.001). Conclusion Visual management health education can effectively improve the effect of health education, increase patients' awareness, compliance and satisfaction with VTE prevention, reduce the risk of lower limb VTE, and improve the coagulation function of CTO patients during PCI.

Knowing the pathophysiology of trauma-induced coagulopathy is important for the management of severely injured trauma patients. The aims of this review are to provide a summary of the recent advances in our understanding of thrombosis and hemostasis following trauma and to discuss the pathogenesis of disseminated intravascular coagulation (DIC) at an early stage of trauma. Local hemostasis and thrombosis respectively act to induce physiological wound healing of injuries and innate immune responses to damaged-self following trauma. However, if overwhelmed by systemic inflammation caused by extensive tissue damage and tissue hypoperfusion, both of these processes foster systemic DIC associated with pathological fibrin(ogen)olysis. This is called DIC with the fibrinolytic phenotype, which is characterized by the activation of coagulation, consumption coagulopathy, insufficient control of coagulation, and increased fibrin(ogen)olysis. Irrespective of microvascular thrombosis, the condition shows systemic thrombin generation as well as its activation in the circulation and extensive damage to the microvasculature endothelium. DIC with the fibrinolytic phenotype gives rise to oozing-type non-surgical bleeding and greatly affects the prognosis of trauma patients. The coexistences of hypothermia, acidosis, and dilution aggravate DIC and lead to so-called trauma-induced coagulopathy. He that would know what shall be must consider what has been. The Analects of Confucius.

Ultralow molecular weight (ULAAW) heparins are sulfated glycans that are clinically used to treat thrombotic disorders. ULMW heparins range from 1500 to 3000 daltons, corresponding from 5 to 10 saccharide units. The commercial drug Arixtra (fondaparinux sodium) is a structurally homogeneous ULMW heparin pentasaccharide that is synthesized through a lengthy chemical process. Here, we report 10- and 12-step chemoenzymatic syntheses of two structurally homogeneous ULMW heparins (MW = 1778.5 and 1816.5) in 45 and 37% overall yield, respectively, starting from a simple disaccharide. These ULMW heparins display excellent in vitro anticoagulant activity and comparable pharmacokinetic properties to Arixtra, as demonstrated in a rabbit model. The chemoenzymatic approach is scalable and shows promise for a more efficient route to synthesize this important class of medicinal agent.

Tissue factor (TF) expressed on sub-cellular membrane vesicles, so-called plasma microparticles (MPs), has recently emerged as a potential key player in intravascular coagulation activation in various disease states. In this report, we demonstrate significantly increased levels of TF-specific procoagulant activity (PCA) of plasma MPs in five patients presenting with overt disseminated intravascular coagulation (DIC) due to an underlying malignancy, including non-small-cell lung cancer ( n  = 1), melanoma ( n  = 1), prostate cancer ( n  = 2), and acute promyelocytic leukemia ( n  = 1). Clotting experiments on available tumor cell samples suggested that cancer cells were a potential source of circulating TF-positive MPs at least in three of the five patients. Furthermore, follow-up plasma samples from two surviving patients revealed that response of their malignancies to specific anti-cancer therapy was paralleled by resolution of overt DIC and a significant decline in MP-associated TF PCA. Levels of plasma TF antigen, as assessed by an enzyme-linked immunosorbent assay, were also increased at presentation albeit to a lesser extent compared to MP-associated TF PCA, likely due to insufficient solubilization of the phospholipid-incorporated full-length TF molecule by the detergent. In summary, our findings suggest that MP-associated TF PCA may play an important pathogenic role in the evolution of overt DIC in various types of malignancy.