Plasminogen Concentration Research Articles

The Impact of Negative Energy Balance in Holstein-Friesian Cows on the Blood Concentrations of Interleukin-6 and Plasminogen.

Background/Objectives: The negative energy balance activaties of spontaneous lipolysis. This may promotes inflammation within the adipose tissue. The aim of the study was to explain the development of inflammation during increased lactogenesis. It was hypothesized that lipolysis contributes synthesis of interleukin-6 and plasminogen. Methods: The study was in production conditions carried out using Holstein-Friesian cows. The period studied covered time of early lactation. Results: Up to the peak of lactation, milk yield strongly influenced the rate of loss of body condition. This had an impact on with the intensity of the release of the fatty acids. In both cases this relationships strengthened to the peak of production. Oobserved tendencies towards a decrease in the concentration of glucose and an increase in that of leptin. Loss of the body condition and the release of NEFA were were influencing to affect the blood concentrations of interleukin-6 and plasminogen. We have shown that IL-6 has a relatively strong correlation with the NEFA. They correlate with IL-6 independently of EB influence. This may suggest independent associations between these variables, which could potentially be applied in practice. Conclusions: The NEFA release in the long term can increase the inflammatory response within adipose tissue and can intensify the release of interleukin-6 and plasminogen. It is likely that in the initial stage of lactogenesis, the inflammatory process developing within adipose tissue is physiologically justified. Our results can provide background to this little-described area of research.

A sorbent modified with melatonin and lithium: in vitro investigation of the effect on hemostatic reactions

Aim of the study was to evaluate the effect of lithium- and melatonin-containing sorbent based on aluminum oxide and polydimethylsiloxane on changes in the number of platelets during hemosorption modeling and on the features of the hemostatic response during dosed contact of the sorbent with blood in an in vitro experiment. Material and methods. An analysis of the effect of the porous sorbent modified with melatonin (MT, 0.15 %) and lithium (0.5 %) based on aluminum oxide and polydimethylsiloxane (Al2O3@PDMS/MT-Li) was carried out in comparison with sorbent without modifiers (Al2O3@PDMS) and modified with MT (Al2O3@PDMS/MT) on a number of donor blood clotting parameters under in vitro hemosorption conditions. Studies of the hemostatic system included assessment of platelet count, chronometric parameters, fibrinogen concentration, antithrombin activity and plasminogen content. For integral assessment, calibrated thrombography and computer thromboelastometry were used. Results and discussion. Contact of all studied sorbents with blood causes a moderate decrease in the number of platelets (by 5.3–10.1 % from initial). Comparison sorbents reduce fibrinogen concentration by 7.1–7.7 %, Al2O3@PDMS/MT-Li – by 2.6 times, which is likely due to the methodology for determining this protein against the background of the independent anticoagulant activity of lithium ions. Al2O3@PDMS and Al2O3@PDMS/MT cause the development of a hypercoagulable shift, as evidenced by a shortening of kaolin time (by 27.5 and 22.1 %, respectively) and of activated partial thromboplastin time (APTT) by 7.1 % for both sorbents. At the same time, when lithium was included in the sorbent, not only did the hypercoagulation shift not occur, but blood clotting was also inhibited, as evidenced by an increase in kaolin time and APTT by 1.2 and 1.6 times, respectively, as well as in silicone time. Conclusions. Modifying sorbents with biologically active substances, lithium and MT, makes it possible to obtain an original hemosorbent with new properties. The presented results demonstrated the absence of a hypercoagulable shift in donor blood after contact with a lithium-, MTcontaining sorbent in vitro and indicate the potential for its using as a basis for the development of safe drugs.

A Study on Plasminogen-Ag Nanoparticles Interaction and its Application in Sensor Development

The interaction between plasminogen and Ag nanoparticles is studied using different techniques and applied for plasminogen sensor development. Ag nanoparticles are synthesized using an algal extract and their absorbance, emission, and electrochemical oxidation signals are detected and monitored as a function of plasminogen concentration. The variation in the optical and electrochemical properties of Ag nanoparticles is correlated with the changes in the hydrodynamic size of the bioconjugate at different plasminogen concentrations. A steady decrease in the absorbance and electrochemical oxidation peak of Ag nanoparticles is observed, while a threshold plasminogen concentration results in increasing the emission of Ag nanoparticles followed by a steady decrease in signal. The decrease in the optical and electrochemical oxidation signal of Ag nanoparticles agrees with the plasminogen-induced Ag nanoparticle agglomeration shown by dynamic light scattering. Calibration curves are established based on the absorbance, emission, and voltammetric studies obtaining a limit of detection as low as 0.740 nM with a wide linear range of 0.942-18.2 nM, which is a very promising analytical system for plasminogen detection, facilitating its progress as a biomarker for different biomedical applications.

Evaluation of proteolytic activity and serine proteases distribution in plasma from patients with bladder cancer.

Bladder cancer (BC) is an aggressive disease with a poor prognosis. A bladder tumor, like other malignant neoplasms, is characterized by the presence of both cancer cells and stromal cells which secrete cytokines, chemokines, growth factors, and proteolytic enzymes. One such class of proteolytic enzymes are serine proteases, which take part in the tumor microenvironment formation via supporting and contributing to tumor progression. This study aims to evaluate the proteolytic activity and serine protease contribution in plasma from BC patients. The research involved patients of Alexandrovsky city clinical hospital aged 52-76 with transitional cell carcinoma of the bladder. All examined patients were divided into five groups: the control group included conditionally healthy donors, while other patients were grouped according to their tumor stage (I, II, III and IV). Plasma plasminogen levels were determined by enzyme-linked immunosorbent assay, and the potential activity was measured by chromogenic plasminogen assay. Serine proteases fractions were obtained by the affinity chromatography method, and enzyme concentration in the selected fractions were determined by the Bradford method. Serine proteases distribution was investigated by electrophoresis in a polyacrylamide gel. It was determined that the concentration, potential activity of plasminogen, and the total amount of serine proteases in plasma from BC patients were greater than the values of the corresponding indicators in healthy donors. This could be one of the factors contributing to increased proteolysis seen in the process of carcinogenesis. Plasminogen concentration in BC patients with stage IV disease; however, displayed a tendency to be reduced compared to earlier stages, and the potential activity of plasminogen was significantly lower in patients with stages III - IV BC. Futhermore, a tumor stage specific gradual decline in the serine protease plasma content was shown. The results of electrophoretic analysis established a significant diminishment in the percentage of high molecular weight components (under non-reducing conditions) and their complete disappearance (under reducing conditions) in plasma serine protease fractions from BC patients. A decline in the percentage of heavy and light plasmin chains in BC patients was also observed. Additionally, a rise in the degraded forms of plasminogen/plasmin content was seen in BC samples, as well as the presence of fractions corresponding to trypsin and NE (under non-reducing conditions) that were absent in the control samples. The results indicate significant changes in the proteolytic activity of plasma, from BC patients when compared to healthy controls, which is accompanied by alterations in serine protease distribution caused by tumor microenvironment pecularlities at the different stages of oncopathology.

The role of plasminogen and urokinase activator of plasminogen in the treatment of endogenous uveitis in children

AIM: To determine the content of plasminogen and urokinase activator of plasminogen in tears and blood serum and to identify correlations between the studied parameters and the clinical picture of uveitis.
 MATERIAL AND METHODS: One hundred thirty-three eyes with uveitis were examined in 74 patients aged 3 to 17 yr (average 10.453.35 yr). The content of the urokinase activator of plasminogen (UPA) was studied in 188 tear samples and 22 blood serum samples. The dynamics of UPA in tears were studied in 28 patients (51 eyes). The plasminogen content of 86 tear samples and 34 blood serum samples was studied. The dynamics of plasminogen in tears were studied in five patients (nine eyes). The concentrations of UPA and plasminogen were measured using the ELISA method and the kits ELISA kit for plasminogen activator, urokinase (UPA)/ELISA Kit for Plasminogen, Cloud-Clone Corp., USA).
 RESULTS: An increase in the content of UPA in the tears of children with uveitis was associated with higher inflammatory activity (p=0.04). An increase in the content of UPA in tears was associated with an increase in the degree of proliferative changes (p=0.04). An increase in the content of UPA and plasminogen in tears was found 12 months after surgery. There was an increase in the content of UPA (p=0.0001) and plasminogen in tears (p=0.009) and blood serum (p=0.09) with age.
 CONCLUSION: The content of UPA in tears increased significantly when severe uveitis was compared with inactive uveitis. An increase in the content of UPA in tears was associated with an increase in the degree of proliferative changes, which reflects the severity of the uveitis course. The content of UPA and plasminogen in tears and blood serum increased with age. An increase in UPA and plasminogen was observed within 12 months after surgery, with both returning to preoperative values by the third month of the postoperative period, which reflects the normal course of the wound healing process.

Temporal Changes in Extracellular Vesicle Hemostatic Protein Composition Predict Favourable Left Ventricular Remodeling after Acute Myocardial Infarction.

The subset of plasma extracellular vesicles (EVs) that coprecipitate with low-density lipoprotein (LDL-EVs) carry coagulation and fibrinolysis pathway proteins as cargo. We investigated the association between LDL-EV hemostatic/fibrinolysis protein ratios and post-acute myocardial infarction (post-AMI) left ventricular (LV) remodeling which precedes heart failure. Protein concentrations of von Willebrand factor (VWF), SerpinC1 and plasminogen were determined in LDL-EVs extracted from plasma samples obtained at baseline (within 72 h post-AMI), 1 month and 6 months post-AMI from 198 patients. Patients were categorized as exhibiting adverse (n = 98) or reverse (n = 100) LV remodeling based on changes in LV end-systolic volume (increased or decreased ≥15) over a 6-month period. Multiple level longitudinal data analysis with structural equation (ML-SEM) model was used to assess predictive value for LV remodeling independent of baseline differences. At baseline, protein levels of VWF, SerpinC1 and plasminogen in LDL-EVs did not differ between patients with adverse versus reverse LV remodeling. At 1 month post-AMI, protein levels of VWF and SerpinC1 decreased whilst plasminogen increased in patients with adverse LV remodeling. In contrast, VWF and plasminogen decreased whilst SerpinC1 remained unchanged in patients with reverse LV remodeling. Overall, compared with patients with adverse LV remodeling, higher levels of SerpinC1 and VWF but lower levels of plasminogen resulted in higher ratios of VWF:Plasminogen and SerpinC1:Plasminogen at both 1 month and 6 months post-AMI in patients with reverse LV remodeling. More importantly, ratios VWF:Plasminogen (AUC = 0.674) and SerpinC1:Plasminogen (AUC = 0.712) displayed markedly better prognostic power than NT-proBNP (AUC = 0.384), troponin-I (AUC = 0.467) or troponin-T (AUC = 0.389) (p < 0.001) to predict reverse LV remodeling post-AMI. Temporal changes in the ratios of coagulation to fibrinolysis pathway proteins in LDL-EVs outperform current standard plasma biomarkers in predicting post-AMI reverse LV remodeling. Our findings may provide clinical cues to uncover the cellular mechanisms underpinning post-AMI reverse LV remodeling.

Adipokines and adipocytokines in men with coronary atherosclerosis and overweight

Aim To study concentrations of adipokines and their associations with proinflammatory cytokines in overweight men with coronary atherosclerosis.Material and methods This study included 79 men aged 45-60 years with atherosclerosis who had undergone coronary endarterectomy during a coronary bypass surgery, and were overweight (body weight index (BWI), 25.0-29.9 kg /m2). Based on a histological analysis of plaques, the patients were divided into two subgroups: 43 men with stable atherosclerotic plaques and 36 men with unstable plaques in coronary arteries. The control group consisted of 40 age- and BWI-matched men without clinical manifestations of IHD. Blood concentrations of adipokines, including adiponectin, adipsin, lipocalin-2, resistin, and plasminogen 1 activator inhibitor were measured by a multiplex analysis with a MILLIPLEX MAP Human Adipokine Panel 1. Concentrations of proinflammatory cytokines, including tumor necrosis factor α (TNF- α), interleukin (IL)-1β, IL-6, and C-reactive protein (CRP) were measured by enzyme immunoassay.Results The blood concentration of lipocalin -2 was higher in patients with coronary atherosclerosis and stable or unstable atherosclerotic plaques than in the control group (p&lt;0.01). Both subgroups of men with coronary atherosclerosis were characterized by significant differences from the control group in concentrations of TNF-α (p&lt;0.05), CRP, and IL-6 (p&lt;0.01). The most significant direct correlations were found between adipokines and TNF-α, IL-6, and CRP (p&lt;0.01). Results of a logistic regression analysis showed that relative odds for the presence of significant coronary stenoses increased with increasing blood concentrations of lipocalin-2 (OR=1.005, 95 % CI: 1.002-1.008, р=0.011) and IL-6 (OR=1.582 , 95 % CI: 1.241-2.017, р=0.001).Conclusion The changes in blood concentrations of adipokines associated with higher levels of proinflammatory cytokines may represent a factor that increases the probability of clinically significant coronary stenosis in overweight men with coronary atherosclerosis.

Abstract 10433: Inhibition of Plasminogen Activator Inhibitor Type 1 in Experimental Venous Thrombosis

Introduction: Conventional treatment of deep vein thrombosis is suboptimal, requiring continuous improvement in knowledge about the disease and a search for new therapeutic approaches. Hypothesis: Blood flow affects the composition of an acute venous thrombus (VT). Aim 1: Compare VT composition under flow and stasis conditions. Aim 2: Evaluate the antithrombotic properties of the novel PAI-1 inhibitor MDI-2268 in-vivo. Methods: C57BL/6 mice, 10-12w, 20-25g were used in electrolytic (EIM) and ligation (LM) models of venous thrombosis. Aim 1: The thrombus weight (TW) and the microstructure of an acute VT (Day 2) in the EIM (n=5) and the LM (n=5) were compared. Expression of PAI-1, tPA, and uPA in the vein wall and plasma levels of D-dimer were investigated. Aim 2: Five EIM groups (n=5) were studied: MDI-2268 1.5 mg/kg (Group 1), MDI-2268 3 mg/kg (Group 2), enoxaparin 7.3 mg/kg (Group 3), MDI-2268 3 mg/kg plus enoxaparin 1.8 mg/kg (Group 4), and DMSO controls (Group 5). TW and bleeding time (BT) on Day 2 were measured. Results: Aim 1: VT within the EIM was smaller compared to the LM (6.2.5±3.6 vs. 26.2±3.6, P&lt;0.05). VT formed within the EIM had a significantly higher amount of plasminogen. The level of D-dimer was 23.4±12.5 and 4.5±1.3 ng/mL/mg in the EIM and LM, respectively (p&lt;0.05). Aim 2: TW was 6.9±3.3 (p&gt;.05), 5.5±1.6 (p=.035), 3.8±1.3 (p=.005), and 4.8±2.4 mg (p=.035) for groups 1,2,3, and 4; compared to 12.7±5.7 mg in the controls. BT was not affected by the MDI-2268. Conclusions: Blood flow pattern significantly affects VT composition. Non-occlusive thrombus has a higher potential to be targeted by the fibrinolytic system due to a higher plasminogen content. MDI-2268 demonstrates strong antithrombotic properties in-vivo and may be associated with a lower risk of bleeding compared to enoxaparin. This data may contribute to a better understanding of the disease process, different outcomes after venous thrombosis, and new therapeutic targets.

PREDICTORS OF THROMBOGENICITY AND DEVELOPMENT OF ENDOTHELIITIS IN PATIENTS WITH СOVID-19 — ASSOCIATED CARDIAC AND VASCULAR SURGICAL PATHOLOGY IN THE ACUTE AND POST-COVID PERIODS

PREDICTORS OF THROMBOGENICITY AND DEVELOPMENT OF ENDOTHELIITIS IN PATIENTS WITH СOVID-19 — ASSOCIATED CARDIAC AND VASCULAR SURGICAL PATHOLOGY IN THE ACUTE AND POST-COVID PERIODS

Hemostasis System and Plasminogen Activity in Retrochorial Hematoma in the First Trimester of Pregnancy.

(1) Background: The components of the fibrinolytic system and its main component, plasminogen, play a key role in the first months of pregnancy. The effect of autoantibodies interacting with plasminogen in the formation of retrochorial hematoma is unknown. The aim of our study was to determine the role of plasminogen and IgA, IgM, and IgG, which bind to plasminogen, in retrochorial hematoma. (2) Methods: Prothrombin time (PT), thrombin time (TT), partial activated thromboplastin time (aPTT), soluble fibrin-monomer complex (SFMC), D-dimer, plasminogen activity (%Plg), plasminogen concentration (Plg), and the levels of IgG (IgG-Plg), IgM (IgM-Plg), IgA (IgA-Plg) interacting with plasminogen were determined in plasma samples of 57 women with normal pregnancy and 16 with retrochorial hematoma. (3) Results: %Plg in plasma samples from women with retrochorial hematoma was significantly lower than in plasma samples from women with normal pregnancy. The diagnostic significance of %Plg in the ROC analysis was AUC = 0.85. A direct correlation was found between aPTT and the level of autologous IgM interacting with plasminogen. (4) Conclusions: A decrease in the activity of plasminogen in the blood serum of women in the first trimester of pregnancy may indicate disturbances in the hemostasis system and the formation of retrochorial hematoma. According to the results of the study, it is possible to recommend the determination of plasminogen activity in the management of pregnant women in gynecological practice.

Plasminogen and plasmin can bind to human T cells and generate truncated CCL21 that increases dendritic cell chemotactic responses

Plasmin is a broad-spectrum protease and therefore needs to be tightly regulated. Active plasmin is formed from plasminogen, which is found in high concentrations in the blood and is converted by the plasminogen activators. In the circulation, high levels of α2-antiplasmin rapidly and efficiently inhibit plasmin activity. Certain myeloid immune cells have been shown to bind plasmin and plasminogen on their cell surface via proteins that bind to the plasmin(ogen) kringle domains. Our earlier work showed that T cells can activate plasmin but that they do not themselves express plasminogen. Here, we demonstrate that T cells express several known plasminogen receptors and that they bind plasminogen on their cell surface. We show T cell–bound plasminogen was converted to plasmin by plasminogen activators upon T cell activation. To examine functional consequences of plasmin generation by activated T cells, we investigated its effect on the chemokine, C-C motif chemokine ligand 21 (CCL21). Video microscopy and Western blotting confirmed that plasmin bound by human T cells cleaves CCL21 and increases the chemotactic response of monocyte-derived dendritic cells toward higher CCL21 concentrations along the concentration gradient by increasing their directional migration and track straightness. These results demonstrate how migrating T cells and potentially other activated immune cells may co-opt a powerful proteolytic system from the plasma toward immune processes in the peripheral tissues, where α2-antiplasmin is more likely to be absent. We propose that plasminogen bound to migrating immune cells may strongly modulate chemokine responses in peripheral tissues.

Breaking the fibrinolytic speed limit with microwheel co‐delivery of tissue plasminogen activator and plasminogen

BackgroundTo reestablish blood flow in vessels occluded by clots, tissue plasminogen activator (tPA) can be used; however, its efficacy is limited by transport to and into a clot and by the depletion of its substrate, plasminogen. ObjectivesTo overcome these rate limitations, a platform was designed to co‐deliver tPA and plasminogen based on microwheels (µwheels), wheel‐like assemblies of superparamagnetic colloidal beads that roll along surfaces at high speeds. MethodsThe biochemical speed limit was determined by measuring fibrinolysis of plasma clots at varying concentrations of tPA (10–800 nM) and plasminogen (1–6 µM). Biotinylated magnetic mesoporous silica nanoparticles were synthesized and bound to streptavidin‐coated superparamagnetic beads to make studded beads. Studded beads were loaded with plasminogen and tPA was immobilized on their surface. Plasminogen release and tPA activity were measured on the studded beads. Studded beads were assembled into µwheels with rotating magnetic fields and fibrinolysis of plasma clots was measured in a microfluidic device. ResultsThe biochemical speed limit for plasma clots was ~15 µm/min. Plasminogen‐loaded, tPA‐immobilized µwheels lyse plasma clots at rates comparableto the biochemical speed limit. With the addition of a corkscrew motion, µwheels penetrate clots, thereby exceeding the biochemical speed limit (~20 µm/min) and achieving lysis rates 40‐fold higher than 50 nM tPA. ConclusionsCo‐delivery of an immobilized enzyme and its substrate via a microbot capable of mechanical work has the potential to target and rapidly lyse clots that are inaccessible by mechanical thrombectomy devices or recalcitrant to systemic tPA delivery.

Vascular and vegetative factors of glaucoma attack

Purpose. To study the involvement of vascular and vegetative factors in the pathogenesis of glaucoma attack. Material and methods. 12 patients (24 eyes) aged 49 to 82 — 5 men and 7 women, including 3 patients with acute glaucoma and 9 patients with subacute glaucoma were subjected to an ophthalmological examination that included visometry, tonometry, automated static perimetry, OCT and OCT angiography. They were also tested for heart rate variability (HRV) using a Polar heart rate monitor, and for plasminogen content and products of fibrin/fibrinogen degradation in the tear. For comparison, the contralateral eyes of these patients were examined. Results. In the eyes with an acute glaucoma attack, the vascular network was noticeably weakened, especially in the area of the deep peripapillary vascular plexus at the lamina cribrosa level, and focal capillary loss was observed. The peripapillary density of the deep vascular plexus in the eyes with an acute attack was 33.0 ± 5.6 % (М ± m), which was significantly (p &lt; 0.01) lower as compared to 50.0 ± 4.7 % in the unaffected eyes. This indicator correlated with the thickness of the ganglion cell complex (GCC) (p &lt; 0.01). In unaffected eyes, no correlations were found between these glaucoma-related parameters. A significant amount of fibrin/fibrinogen degradation products was found in the tear of glaucoma patients, which may point to a violation of blood circulation in the optic nerve vessels. It has been established that glaucoma attack occurs with increased activity of sympathetic regulation of blood flow. Conclusion. When monitoring this contingent of patients, it is essential to determine the sympathetic-parasympathetic status of the patient. Taking into account the vascular component of the condition, it is expedient to introduce the necessary additions into its treatment plans

Characteristics of blood proteome changes in hemorrhagic syndrome after head-up tilt test during 21-day Dry Immersion

The effect of the rapid redistribution of blood during head-up tilt tests in 21-day Dry Immersion suddenly became relevant in connection with the occurrence of mild hemorrhagic syndrome in the study participants. It became necessary to analyze the processes of occurrence of hemorrhagic syndrome as orthostatic and congestive purpura. The aim of this work was to study the features of the proteomic response of the human body to the rapid redistribution of blood during head-up tilt tests during 21-day immersion, which led to stagnant and orthostatic purpura. According to the results of examination of 10 healthy male volunteers aged 23–34 years after head-up tilt tests, pitting edema and local petechial hemorrhages in the soft tissues of the legs and feet were observed. Proteomic analysis of the samples was carried out by high performance liquid chromatography with tandem mass spectrometry. For bioinformatic analysis, the software packages Perseus, ANDSystem were used. From reliably different (p-value <0.05) proteins, proteins directly related to injury and changes in vascular permeability were determined. Сhanges in the levels of plasminogen, fibronectin, other factors of coagulation and fibrinolysis, activation of the complement system, changes in the coagulation cascade and concentrations of plasminogen and its activators (kallikrein, etc.), increased content of fibrinolysis products were revealed. A panel of proteins indicating changes in plasmin-antiplasmin, fibrinogen-soluble fibrin-monomeric complexes and other systems is identified. The obtained data are of scientific and practical interest in the direction of stratification of the risk of secondary hemosiderosis and evaluation of new treatment methods aimed at reducing reperfusion damage to soft tissues and parenchymal organs.

Exposure of plasminogen and a novel plasminogen receptor, Plg-RKT, on activated human and murine platelets

AbstractPlasminogen activation rates are enhanced by cell surface binding. We previously demonstrated that exogenous plasminogen binds to phosphatidylserine-exposing and spread platelets. Platelets contain plasminogen in their α-granules, but secretion of plasminogen from platelets has not been studied. Recently, a novel transmembrane lysine-dependent plasminogen receptor, Plg-RKT, has been described on macrophages. Here, we analyzed the pool of plasminogen in platelets and examined whether platelets express Plg-RKT. Plasminogen content of the supernatant of resting and collagen/thrombin-stimulated platelets was similar. Pretreatment with the lysine analog, ε-aminocaproic acid, significantly increased platelet-derived plasminogen (0.33 vs 0.08 nmol/108 platelets) in the stimulated supernatant, indicating a lysine-dependent mechanism of membrane retention. Lysine-dependent, platelet-derived plasminogen retention on thrombin and convulxin activated human platelets was confirmed by flow cytometry. Platelets initiated fibrinolytic activity in fluorescently labeled plasminogen-deficient clots and in turbidimetric clot lysis assays. A 17-kDa band, consistent with Plg-RKT, was detected in the platelet membrane fraction by western blotting. Confocal microscopy of stimulated platelets revealed Plg-RKT colocalized with platelet-derived plasminogen on the activated platelet membrane. Plasminogen exposure was significantly attenuated in thrombin- and convulxin-stimulated platelets from Plg-RKT−/− mice compared with Plg-RKT+/+ littermates. Membrane exposure of Plg-RKT was not dependent on plasminogen, as similar levels of the receptor were detected in plasminogen−/− platelets. These data highlight Plg-RKT as a novel plasminogen receptor in human and murine platelets. We show for the first time that platelet-derived plasminogen is retained on the activated platelet membrane and drives local fibrinolysis by enhancing cell surface–mediated plasminogen activation.

Circulating Plasminogen Concentration at Admission in Patients with Coronavirus Disease 2019 (COVID-19).

The pathophysiology of coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has puzzled the medical community, hampering the ability to generate efficient targeted therapies.[1] Although SARS-CoV-2 is considered a primary respiratory pathogen, COVID-19 should be instead characterized as both a respiratory and systemic thrombotic disease.[2] Conventionally termed COVID-19-associated coagulopathy (CAC), this hypercoagulable state is characterized by high risk of developing micro- and macrothromboemboli, impacting both arteries and veins.[2] While initially affecting the pulmonary microvasculature, systemic involvement develops as the disease progresses, leading to thrombosis in distant organs and multiorgan dysfunction syndrome.[2]

Thrombosis of the Abdominal Aorta in a Extremely Low Birth Weight Infant: Treatment with Tissue-Type Plasminogen Activator

Aortic thrombosis during neonatal period is a rare event especially when it is not related to umbilical arterial catheters. A case of a premature infant with a gestational age of 25 weeks who suddenly developed, at the age of 44 days, poor arterial saturation (SaO2 60%) and legs pale and painful, is reported. In this patient, arterial and venous eco-color Doppler showed a complete aortic thrombosis distal to the renal arteries of unknown etiology. Thrombolytic therapy with tissue-type plasminogen activator (t-PA) was immediately started with a bolus dose of 0.5 mg/kg/h followed by a continuous infusion of 0.2 mg/kg/h. Fresh frozen plasma was also infused in order to increase the concentration of plasminogen. We tried with success to avoid bleeding complications maintaining fibrinogen concentration over 500 mg/L and platelets over 100,000x109/L. Heparinisation with enoxaparin was started after 5 days of t-PA treatment and continued for 85 days. The premature infant recovered but physiotherapy and splints were needed for talipes equinovarus resulted as a consequence of distal thrombosis. Conclusion: The strategy for treating an acute arterial thrombosis in a neonate may include thrombolytic therapy with t-PA, taking into account that the rate of plasmin generation in newborns and overall activity is decreased compared to adults. The impaired response of newborns may be enhanced not by increasing the dose of t-PA but increasing plasminogen through fresh frozen plasma infusion.

UPA-mediated plasminogen activation is enhanced by polyphosphate.

Tissue plasminogen activator (tPA) and urokinase plasminogen activator (uPA) differ in their modes of action. Efficient tPA-mediated plasminogen activation requires binding to fibrin. In contrast, uPA is fibrin independent and activates plasminogen in solution or when associated with its cellular receptor urokinase protease activated receptor (uPAR). We have previously shown that polyphosphate (polyP), alters fibrin structure and attenuates tPA and plasminogen binding to fibrin, thereby down-regulating fibrinolysis. Here we investigate the impact of polyP on uPA-mediated fibrinolysis. As previously reported polyP of an average chain length of 65 (polyP65) delays tPA-mediated fibrinolysis. The rate of plasmin generation was also delayed and reduced 1.6-fold in polyP65 -containing clots (0.74±0.06 vs. 1.17±0.14 pM/s in P<0.05). Analysis of tPA-mediated fibrinolysis in real-time by confocal microscopy was significantly slower in polyP65 -containing clots. In marked contrast, polyP65 augmented the rate of uPA-mediated plasmin generation 4.7-fold (3.96±0.34 vs. 0.84±0.08 pM/s; P<0.001) and acce-lerated fibrinolysis (t1/2 64.5±1.7 min vs. 108.2±3.8 min; P<0.001). Analysis of lysis in real-time confirmed that polyP65 enhanced uPA-mediated fibrino- lysis. Varying the plasminogen concentration (0.125-1 mM) in clots dose-dependently enhanced uPA-mediated fibrinolysis, while negligible changes were observed on tPA-mediated fibrinolysis. The accelerating effect of polyP65 on uPA-mediated fibrinolysis was overcome by additional plasminogen, while the down-regulation of tPA-mediated lysis and plasmin generation was largely unaffected. polyP65 exerts opposing effects on tPA- and uPA-mediated fibrinolysis, attenuating the fibrin cofactor function in tPA-media-ted plasminogen activation. In contrast, polyP may facilitate the interaction between fibrin-independent uPA and plasminogen thereby accelerating plasmin generation and downstream fibrinolysis.

Potent reduction of plasma lipoprotein (a) with an antisense oligonucleotide in human subjects does not affect ex vivo fibrinolysis

It is postulated that lipoprotein (a) [Lp(a)] inhibits fibrinolysis, but this hypothesis has not been tested in humans due to the lack of specific Lp(a) lowering agents. Patients with elevated Lp(a) were randomized to antisense oligonucleotide [IONIS-APO(a)Rx] directed to apo(a) (n = 7) or placebo (n = 10). Ex vivo plasma lysis times and antigen concentrations of plasminogen, factor XI, plasminogen activator inhibitor 1, thrombin activatable fibrinolysis inhibitor, and fibrinogen at baseline, day 85/92/99 (peak drug effect), and day 190 (3 months off drug) were measured. The mean ± SD baseline Lp(a) levels were 477.3 ± 55.9 nmol/l in IONIS-APO(a)Rx and 362.1 ± 89.9 nmol/l in placebo. The mean± SD percentage change in Lp(a) for IONIS-APO(a)Rx was -69.3 ± 12.2% versus -5.4 ± 6.9% placebo (P < 0.0010) at day 85/92/99 and -15.6 ± 8.9% versus 3.2 ± 12.2% (P = 0.003) at day 190. Clot lysis times and coagulation/fibrinolysis-related biomarkers showed no significant differences between IONIS-APO(a)Rx and placebo at all time points. Clot lysis times were not affected by exogenously added Lp(a) at concentrations up to 200 nmol/l to plasma with very low (12.5 nmol/l) Lp(a) levels, whereas recombinant apo(a) had a potent antifibrinolytic effect. In conclusion, potent reductions of Lp(a) in patients with highly elevated Lp(a) levels do not affect ex vivo measures of fibrinolysis; the relevance of any putative antifibrinolytic effects of Lp(a) in vivo needs further study.

DNA-bound elastase of neutrophil extracellular traps degrades plasminogen, reduces plasmin formation, and decreases fibrinolysis: proof of concept in septic shock plasma.

Activation of platelets and neutrophils in septic shock results in the formation of microvascular clots containing an intricate scaffold of fibrin with neutrophil extracellular traps (NETs) DNA. NETs contain multiple components that might impact endogenous fibrinolysis, resulting in failure to lyse clots in the microcirculation and residual systemic microthrombosis. We propose herein that the reservoir of human neutrophil elastase (HNE) on NETs may directly interfere with the fibrinolytic mechanism via a plasminogen proteolytic pathway. To investigate this mechanism, we constructed fibrin-NETs matrices by seeding and activating neutrophils onto a fibrin surface and monitored plasminogen activation or degradation. We demonstrate that the elastase activity of HNE-DNA complexes is protected from inhibition by plasma antiproteases and sustains its ability to degrade plasminogen. Using mass spectrometry proteomic analysis, we identified plasminogen fragments composed of kringle (K) domains (K1+2+3, k1+2+3+4) and the serine protease (SP) region (K5-SP). We further demonstrate that patients with septic shock with disseminated intravascular coagulation have circulating HNE-DNA complexes, HNE-derived plasminogen fragments, a low plasminogen concentration, and a reduced capacity to generate plasmin onto fibrin. In conclusion, we show that NETs bearing active HNE-DNA complexes reduce plasminogen into fragments, thus impairing fibrinolysis by decreasing the local plasminogen concentration, plasminogen binding to fibrin, and localized plasmin formation.-Barbosa da Cruz, D., Helms, J., Aquino, L. R., Stiel, L., Cougourdan, L., Broussard, C., Chafey, P., Riès-Kautt, M., Meziani, F., Toti, F., Gaussem, P., Anglés-Cano, E. DNA-bound elastase of neutrophil extracellular traps degrades plasminogen, reduces plasmin formation, and decreases fibrinolysis: proof of concept in septic shock plasma.