Fibrinolysis associated proteins and lipopolysaccharide bioactivity in plasma and cerebrospinal fluid in multiple sclerosis.

The coagulation cascade and fibrinolysis have links with neuroinflammation and increased activation of the coagulation system has been reported in MS patients. We quantified levels of D-dimer, tissue plasminogen activator (tPA), plasminogen activator inhibitor-1 (PAI-1) and the bioactivity of bacterial lipopolysaccharide (LPS) in cerebrospinal fluid (CSF) and plasma from newly diagnosed untreated MS patients and controls. These molecules showed multiple correlations with each other as well as with age, HLA-DRB1*15:01, body-mass-index and CSF IgG. Our results confirm previous findings of increased plasma PAI-1 and LPS in MS patients compared to controls indicating changes in platelet function and gut permeability in MS.

Unlocking the potential of HB/RDW ratio as a simple marker for predicting mortality in acute ischemic stroke patients after thrombolysis.

BACKGROUND: Systemic inflammation impairs outcomes in acute ischemic stroke (AIS). There is limited knowledge regarding the prognostic value of inflammatory biomarkers derived from complete blood count in predicting in-hospital mortality (IHM) in AIS patients treated with recombinant tissue plasminogen activator (rt-PA). Our study aims to compare the predictive performance of various inflammatory biomarkers for predicting IHM in AIS patients. METHODS: This retrospective study included AIS patients treated with rt-PA between January 2015 and July 2022. We identified the following inflammatory biomarkers: white blood cell counts (WBCs), absolute neutrophil count, absolute lymphocyte count, neutrophil to lymphocyte count ratio, platelet to neutrophil ratio, platelet to lymphocyte ratio, red cell distribution width (RDW), RDW to platelet ratio (RPR), and hemoglobin to RDW (HB/RDW) at admission before rt-PA administration. We assessed the predictive value of these biomarkers for IHM by plotting receiver operating characteristic (ROC) curves. The associations between inflammatory biomarkers and IHM were analyzed using multivariable logistic regression (MVLR) analyses. RESULTS: Of 345 AIS patients, IHM occurred in 65 patients (18.84%). HB/RDW and RDW showed better predictive performance compared to other inflammatory biomarkers. In ROC curve analysis, HB/RDW and RDW had an area under ROC of 0.668. HB/RDW outperformed RDW in terms of the positive likelihood ratio (2.733 vs 1.575), accuracy (0.757 vs 0.585), specificity (0.814 vs 0.560), and positive predictive values (0.388 vs 0.267). In MVLR analysis, RDW, RPR, and HB/RDW remained significantly associated with IHM (per 1-unit increases: odds ratios (ORs) = 1.450, 95% CI: [1.178-1.784]; per 1-unit increases: ORs = 1.329, 95% CI [1.103-1.602]; and per 0.1-unit decreases: ORs = 1.412, 95% CI [1.089-1.831], respectively). CONCLUSIONS: The association between HB/RDW and IHM in AIS patients treated with rt-PA was significant. HB/RDW exhibited superior predictive performance compared to other inflammatory biomarkers in predicting IHM.

Comparison of coagulation and fibrinolysis in Irish Wolfhounds and age-matched control dogs using tissue plasminogen activator-augmented viscoelastic testing.

OBJECTIVE: To determine if Irish Wolfhounds (IWs), like other sighthounds, are hyperfibrinolytic compared with nonsighthound dogs using 2 native and tissue plasminogen activator (tPA)-enhanced viscoelastic assays, one that is whole blood-based (viscoelastic coagulation monitor [VCM]) and the other that is plasma-based thromboelastography (TEG). DESIGN: Cohort study. SETTING: University teaching hospital. ANIMALS: A convenience sample of 27 IWs recruited from the Irish Wolfhound Association of New England Specialty and the local community, and 27 healthy, age-matched, large-breed control dogs. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Blood samples including CBC, biochemistry, traditional coagulation, and viscoelastic testing were collected from IWs and control dogs. Twelve IWs had viscoelastic testing. IWs had lower fibrinogen concentrations (215.5 ± 57.8 vs 251.4 ± 64.5 mg/dL, P = 0.034) and formed weaker clots on both whole-blood VCM and plasma TEG assays (maximum clot firmness [VCM-MCF] = 39.4 [25.1-48.8] vs 48.5 [34.6-57.3], P = 0.0042; maximum amplitude [TEG-MA] = 22.7 [14.7-33.6] vs 32.2 [26.9-42.0], P < 0.0001). IWs were hyperfibrinolytic compared with control dogs on VCM whole-blood assays, with 25 U/mL tPA (lysis at 30 min [VCM-LI30] = 68.1 [0-100] vs\ 99.9 [63.3-100], P = 0.0009; lysis at 45 min [VCM-LI45] = 31.0 [0-100] vs 98.1 [38.4-100], P = 0.0002) but hypofibrinolytic compared with controls on TEG plasma assays with 50 U/mL tPA (lysis at 30 min [TEG-LY30] = 45.7 [4.6-94.6] vs 93.7 [12.3-96.5], P = 0.0004; lysis at 60 min [TEG-LY60] = 68.7 [29.7-96.8] vs 95.7 [34.4-97.6], P = 0.0003). Minimal fibrinolysis was measured on whole-blood VCM or plasma TEG assays without the addition of tPA, and there were no differences between the 2 groups. CONCLUSIONS: Weaker clots were found in IWs than control dogs. With the addition of tPA, IWs had evidence of hyperfibrinolysis on whole-blood VCM assays and hypofibrinolysis on plasma TEG assays compared with control dogs. Without the addition of tPA, however, both groups of dogs showed minimal fibrinolysis on viscoelastic testing.

Fibrinolysis as a Causative Mechanism for Bleeding Complications on Extracorporeal Membrane Oxygenation: A Pilot Observational Prospective Study.

BACKGROUND: Extracorporeal membrane oxygenation (ECMO) is associated with a high risk of bleeding complications. The specific impact of ECMO on fibrinolysis remains unexplored. The objective of the current pilot observational prospective study was to investigate the longitudinal dynamics of fibrinolytic markers-i.e., changes over time-in the context of bleeding events in patients on ECMO. METHODS: Longitudinal dynamics of contact phase components (kininogen and bradykinin) and fibrinolysis markers (tissue plasminogen activator [tPA], plasminogen activator inhibitor-1 [PAI-1], their complexes [tPA•PAI-1], plasmin-antiplasmin complexes, plasminogen, and D-dimer) were measured in patients undergoing venovenous and venoarterial ECMO, before implantation, at 0, 6, and 12 h after implantation, and daily thereafter. RESULTS: The cohort consisted of 30 patients (214 ECMO days). The concentrations of tPA, D-dimer, plasmin-antiplasmin complexes, PAI-1, and tPA•PAI-1 complexes were increased, whereas plasminogen decreased compared to normal values. A noteworthy divergence was observed between hemorrhagic and nonhemorrhagic patients: in bleeding patients, D-dimer, plasmin-antiplasmin, tPA, PAI-1, and tPA•PAI-1 followed an increasing kinetics before hemorrhage and then decreased to their baseline level; conversely, nonbleeding patients showed a decreasing kinetics in these markers. Also, D-dimer and tPA followed an increasing kinetics in bleeding patients compared to nonbleeding patients (median values for D-dimer dynamics: 1,080 vs. -440 ng/ml, P = 0.05; tPA dynamics: 0.130 vs. 0.100 nM, P = 0.038), and both markers significantly increased the day before hemorrhage. A tPA concentration above 0.304 nM was associated with bleeding events (odds ratio, 4.92; 95% CI, 1.01 to 24.08; P = 0.049). CONCLUSIONS: Contact activation induces fibrinolysis in ECMO patients, especially in patients experiencing bleeding. This finding supports the role of this mechanism as a possible causal factor for hemorrhages during ECMO and open new avenues for novel therapeutic perspectives.

Plasminogen activator inhibitor-1 serum levels in frontotemporal lobar degeneration.

Plasminogen activator inhibitor-1 (PAI-1) impedes brain plasmin synthesis. Reduced plasmin activity facilitates cumulation of amyloid beta (Aß) in Alzheimer's disease (AD). Since plasmin also regulates the synaptic activity, it is possible that altered PAI-1 is present in other neurodegenerative disorders. We investigated whether PAI-1 and its counter-regulatory tissue plasminogen activator (tPA) are altered in serum of patients with dementia due to frontotemporal lobar degeneration (FTLD). Thirty five FTLD patients (21 in mild cognitive impairment stage (MCI) and 14 in dementia stage) and 10 cognitively healthy controls were recruited. Serum tPA and PAI-1 protein levels were measured by anova. Correlation between biochemical and demographic data were explored by measuring Pearson correlation coefficient. Serum PAI-1 levels were elevated in the FTLD dementia group as compared to FTLD MCI and controls. tPA serum levels and PAI-1/tPA ratio did not significantly differ among groups. There was a negative correlation between PAI-1 serum levels and disease severity measured by MMSE score. No correlations of tPA serum levels and PAI-1/tPA ratio with MMSE were found. Increased PAI-1 serum levels may serve as a marker of dementia in FTLD, suggesting that, besides Aß pathway, the plasmin system may affect cognition through synaptic activity.

Identification of soluble thrombomodulin and tissue plasminogen activator-inhibitor complex as biomarkers for prognosis and early evaluation of septic shock and sepsis-induced disseminated intravascular coagulation.

BACKGROUND: Endothelium injury and coagulation dysfunction play an important role in the pathogenesis of sepsis. Soluble thrombomodulin (sTM), tissue plasminogen activator-inhibitor complex (t-PAIC), thrombin-antithrombin complex (TAT) and α2-plasmin inhibitor-plasmin complex (PIC) are biomarkers of endothelium injury and coagulation dysfunction. This study aimed to explore the prognostic values and diagnostic performance for septic shock and sepsis-induced disseminated intravascular coagulation (DIC) of endothelial biomarkers. METHODS: We conducted an observational study on patients with sepsis admitted to intensive care unit (ICU) at a teaching hospital from January 2016 to December 2018. Levels of sTM, t-PAIC, TAT and PIC were measured at admission day and day 5-7 after admission and detected by qualitative chemiluminescence enzyme immunoassay performed on HISCL automated analyzers. RESULTS: A total of 179 septic patients and 125 non-septic ICU controls were enrolled. The level of sTM was higher in septic patients compared to ICU controls (OR =1.093, 95% CI: 1.045-1.151, P<0.001). Moreover, higher levels of sTM and t-PAIC were independent predictors of poor 60-day prognosis for septic patients (HR =1.012, 95% CI: 1.003-1.022, P=0.012; HR =1.014, P=0.009). Level of sTM was also higher in patients with septic shock as revealed by multivariate analysis (OR =1.049, 95% CI: 1.020-1.078, P=0.001), as well as in patients with sepsis-induced DIC (OR =1.109, 95% CI: 1.065-1.158, P<0.001). sTM was considered as a sensitive biomarker for the early prediction of septic shock and sepsis-induced DIC, with AUC up to 0.765 (0.687-0.842) and 0.864 (0.794-0.935) of receiver operating characteristic curve. CONCLUSIONS: Most patients developed coagulopathy which was closely linked to endothelial injury in initial phase of sepsis, which was demonstrated by abnormalities in endothelial biomarkers and their strong association with poor 60-day prognosis and development of septic shock and sepsis-induced DIC.

Coagulation disorders in patients with severe hemophagocytic lymphohistiocytosis.

BACKGROUND: Coagulation disorders are common in patients with hemophagocytic lymphohistiocytosis (HLH), associated with an increased risk of bleeding and death. We aim to investigate coagulation disorders and their outcome implications in critically ill patients with HLH. METHODS: We prospectively evaluated 47 critically ill patients with HLH (median age of 54 years [42-67]) between April 2015 and December 2018. Coagulation assessments were performed at day 1. Abnormal standard coagulation was defined as prothrombin time (PT) <50% and/or fibrinogen <2g/L. HLH aetiology was mostly ascribed to haematological malignancies (74% of patients). RESULTS: Coagulation disorders and severe bleeding events were frequent, occurring in 30 (64%) and 11 (23%) patients respectively. At day 1, median fibrinogen level was 2∙65g/L [1.61-5.66]. Fibrinolytic activity was high as suggested by increased median levels of D-dimers, fibrin monomers, PAI-1 (plasminogen activator inhibitor) and tPA (tissue plasminogen activator). Forty-one (91%) patients had a decreased ADAMTS13 activity (A Disintegrin-like And Metalloproteinase with ThromboSpondin type 1 repeats, member 13). By multivariable analysis, the occurrence of a severe bleeding (OR 3.215 [1.194-8.653], p = 0∙021) and SOFA score (Sepsis-Related Organ Failure Assessment) at day 1 (OR 1.305 per point [1.146-1.485], p<0∙001) were independently associated with hospital mortality. No early biological marker was associated with severe bleeding. CONCLUSIONS: Hyperfibrinolysis may be the primary mechanism responsible for hypofibrinogenemia and may also participate in ADAMTS13 degradation. Targeting the plasmin system appears as a promising approach in severe HLH-related coagulation disorders.

Bundibugyo ebolavirus Survival Is Associated with Early Activation of Adaptive Immunity and Reduced Myeloid-Derived Suppressor Cell Signaling.

Ebolaviruses Bundibugyo virus (BDBV) and Ebola virus (EBOV) cause fatal hemorrhagic disease in humans and nonhuman primates. While the host response to EBOV is well characterized, less is known about BDBV infection. Moreover, immune signatures that mediate natural protection against all ebolaviruses remain poorly defined. To explore these knowledge gaps, we transcriptionally profiled BDBV-infected rhesus macaques, a disease model that results in incomplete lethality. This approach enabled us to identify prognostic indicators. As expected, survival (∼60%) correlated with reduced clinical pathology and circulating infectious virus, although peak viral RNA loads were not significantly different between surviving and nonsurviving macaques. Survivors had higher anti-BDBV antibody titers and transcriptionally derived cytotoxic T cell-, memory B cell-, and plasma cell-type quantities, demonstrating activation of adaptive immunity. Conversely, a poor prognosis was associated with lack of an appropriate adaptive response, sustained innate immune signaling, and higher expression of myeloid-derived suppressor cell (MDSC)-related transcripts (S100A8, S100A9, CEBPB, PTGS2, CXCR1, and LILRA3). MDSCs are potent immunosuppressors of cellular and humoral immunity, and therefore, they represent a potential therapeutic target. Circulating plasminogen activator inhibitor 1 (PAI-1) and tissue plasminogen activator (tPA) levels were also elevated in nonsurvivors and in survivors exhibiting severe illness, emphasizing the importance of maintaining coagulation homeostasis to control disease progression. IMPORTANCE Bundibugyo virus (BDBV) and Ebola virus (EBOV) are ebolaviruses endemic to Africa that cause severe, often fatal hemorrhagic disease. BDBV is considered a less pathogenic ebolavirus due to its reduced lethality during human outbreaks, as well as in experimentally infected nonhuman primates. The reduced mortality of BDBV in NHP models, resulting in a pool of survivors, afforded us the unique opportunity of identifying immune correlates that confer protection against ebolaviruses. In this study, we discovered that the survival of BDBV-infected nonhuman primates (NHPs) was dependent on early development of adaptive (memory) immune responses and reduced myeloid-derived suppressor cell (MDSC)-related signaling. MDSCs are a heterogenous group of immune cells implicated in a number of diseases that are powerful immunosuppressors of cellular and humoral immunity. Thus, MDSCs represent a novel therapeutic target to prevent ebolavirus disease. To our knowledge, this is the first study to link increased morbidity with recruitment of these potent immunosuppressive cells.

Biomarkers of endothelial dysfunction and outcomes in coronavirus disease 2019 (COVID-19) patients: A systematic review and meta-analysis.

BACKGROUND: Several studies have reported that the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can directly infect endothelial cells, and endothelial dysfunction is often found in severe cases of coronavirus disease 2019 (COVID-19). To better understand the prognostic values of endothelial dysfunction in COVID-19-associated coagulopathy, we conducted a systematic review and meta-analysis to assess biomarkers of endothelial cells in patients with COVID-19. METHODS: A literature search was conducted on online databases for observational studies evaluating biomarkers of endothelial dysfunction and composite poor outcomes in COVID-19 patients. RESULTS: A total of 1187 patients from 17 studies were included in this analysis. The estimated pooled means for von Willebrand Factor (VWF) antigen levels in COVID-19 patients was higher compared to healthy control (306.42 [95% confidence interval (CI) 291.37-321.48], p < 0.001; I2:86%), with the highest VWF antigen levels was found in deceased COVID-19 patients (448.57 [95% CI 407.20-489.93], p < 0.001; I2:0%). Meta-analysis showed that higher plasma levels of VWF antigen, tissue-type plasminogen activator (t-PA), plasminogen activator inhibitor-1 antigen (PAI-1) antigen, and soluble thrombomodulin (sTM) were associated with composite poor outcome in COVID-19 patients ([standardized mean difference (SMD) 0.74 [0.33-1.16], p < 0.001; I2:80.4%], [SMD 0.55 [0.19-0.92], p = 0.003; I2:6.4%], [SMD 0.33 [0.04-0.62], p = 0.025; I2:7.9%], and [SMD 0.55 [0.10-0.99], p = 0.015; I2:23.6%], respectively). CONCLUSION: The estimated pooled means show increased levels of VWF antigen in COVID-19 patients. Several biomarkers of endothelial dysfunction, including VFW antigen, t-PA, PAI-1, and sTM, are significantly associated with increased composite poor outcomes in patients with COVID-19. PROSPERO REGISTRATION NUMBER: CRD42021228821.

Regular Resistance Training Enhances Fibrinolytic Potential but Does Not Affect Coagulation.

PURPOSE: This study aimed to identify effects of an 8-wk, whole-body RT program on coagulation and fibrinolysis. METHODS: Sixteen healthy women and men (23 ± 5 yr) completed an RT program three times per week for 8 wk. Exercises included 2-3 sets of 8-12 repetitions performed at approximately 60%-80% of a one repetition maximum. Strength, body composition, and body circumferences were assessed before and after training. Plasma samples were obtained before and after training, and analyzed for active tissue plasminogen activator (tPA activity), total tissue plasminogen activator (tPA antigen), active plasminogen activator inhibitor-1 (PAI-1 activity), total plasminogen activator inhibitor-1 (PAI-1 antigen), fibrinogen, and coagulation factors VII (FVII) and VIII (FVIII). RESULTS: Significant increases in lean mass, arm and thigh circumferences, maximal chest press (PRE: 57.8 ± 37.5 kg, POST: 73.3 ± 43.2 kg), and leg press (PRE: 189.5 ± 96.0 kg, POST: 256.7 ± 97.9 kg) were observed (P < 0.05 for all). PAI-1 activity (PRE: 20.3 ± 32.5 IU·mL-1, POST 9.5 ± 20.9 IU·mL-1) and PAI-1 antigen decreased (PRE: 10.2 ± 9.0 ng·dL-1, POST: 7.2 ± 5.7 ng·dL-1; both, P < 0.05). No change in tPA activity or tPA antigen occurred. Fibrinogen, FVII, and FVIII did not change after training. CONCLUSIONS: Inhibition of fibrinolysis was decreased after training, and coagulation was unaffected. These results suggest that regular RT may beneficially influence the risk of a thrombotic event. More research is warranted to understand the mechanisms through which RT affects hemostasis.

Reverse tracing anti-thrombotic active ingredients from dried Rehmannia Radix based on multidimensional spectrum-effect relationship analysis of steaming and drying for nine cycles.

ETHNOPHARMACOLOGICAL RELEVANCE: In traditional Chinese medicine (TCM) and modern pharmacodynamics, dried Rehmannia Radix (DRR) possesses prominent anti-thrombotic activity that decreases after processing by nine steaming and drying cycles to develop processed Rehmannia Radix (PRR). Due to the complexity of the DRR components, the chemical mechanism leading to efficacy changes of DRR caused by processing is still unclear. AIM OF STUDY: This study aimed to trace the anti-thrombotic active compounds of DRR and different degrees of processed RR (PRR) and to evaluate the synergistic effects among different active components. MATERIALS AND METHODS: The anti-thrombotic active chemical fraction of DRR extracts was evaluated. Targeted fractions of the processed products of RR were prepared at different processing stages. The changes in monosaccharides, oligosaccharides and secondary metabolites during processing were characterized by multidimensional high-performance liquid chromatography (HPLC). The anti-thrombotic effects of targeted fractions of different RR samples were evaluated by analyzing the length of tail thrombus (LT) and serum biochemical indicators in carrageenan-induced tail-thrombus mice. The spectrum-effect relationships were investigated by partial least squares regression (PLSR) analysis and gray correlation analysis (GRA). Finally, the active compounds were screened by spectrum-effect relationship analysis and validated in vivo, and their synergistic effects were determined by Webb's fraction multiplication method. RESULTS: Six ingredients highly associated with anti-thrombotic activities were screened out by the spectrum-effect relationship analysis, of which oligosaccharides (stachyose, sucrose and raffinose) and iridoid glycosides (catalpol, leonuride and melitoside) possessed a synergistic effect on tumor necrosis factors (TNF-α), interleukin 1ß (IL-1ß) and plasminogen activator inhibitor 1 (PAI-1)/tissue-type plasminogen activator (t-PA) ratio in vivo with synergistic coefficient (SC) > 1. CONCLUSION: The main material basis of the anti-thrombotic activities of DRR is oligosaccharide components of stachyose, raffinose and sucrose, iridoid glycosides components of catalpol, leonuride and melittoside. The two kinds of components exert synergistic anti-thrombotic effects by inhibiting the expression of inflammatory factors and regulating the balance of the fibrinolysis system.

Association Between Hemostatic Profile and Migraine: A Mendelian Randomization Analysis.

OBJECTIVE: To assess support for a causal relationship between hemostatic measures and migraine susceptibility using genetic instrumental analysis. METHODS: Two-sample Mendelian randomization instrumental analyses leveraging available genome-wide association study (GWAS) summary statistics were applied to hemostatic measures as potentially causal for migraine and its subtypes, migraine with aura (MA) and migraine without aura (MO). Twelve blood-based measures of hemostasis were examined, including plasma level or activity of 8 hemostatic factors and 2 fibrinopeptides together with 2 hemostasis clinical tests. RESULTS: There were significant instrumental effects between increased coagulation factor VIII activity (FVIII; odds ratio [95% confidence interval] 1.05 [1.03, 1.08]/SD, p = 6.08 × 10-05), von Willebrand factor level (vWF; 1.05 [1.03, 1.08]/SD, p = 2.25 × 10-06), and phosphorylated fibrinopeptide A level (1.13 [1.07, 1.19]/SD, p = 5.44 × 10-06) with migraine susceptibility. When extended to migraine subtypes, FVIII, vWF, and phosphorylated fibrinopeptide A showed slightly stronger effects with MA than overall migraine. Fibrinogen level was inversely linked with MA (0.76 [0.64, 0.91]/SD, p = 2.32 × 10-03) but not overall migraine. None of the hemostatic factors was linked with MO. In sensitivity analysis, effects for fibrinogen and phosphorylated fibrinopeptide A were robust, whereas independent effects of FVIII and vWF could not be distinguished, and FVIII associations were potentially affected by pleiotropy at the ABO locus. Causal effects from migraine to the hemostatic measures were not supported in reverse Mendelian randomization. However, MA was not included due to lack of instruments. CONCLUSIONS: The findings support potential causality of increased FVIII, vWF, and phosphorylated fibrinopeptide A and decreased fibrinogen in migraine susceptibility, especially for MA, potentially revealing etiologic relationships between hemostasis and migraine.

Association between clot composition and stroke origin in mechanical thrombectomy patients: analysis of the Stroke Thromboembolism Registry of Imaging and Pathology.

BACKGROUND: We retrospectively evaluated the composition of retrieved clots from ischemic stroke patients to study the association between histological composition and stroke etiology METHODS: Consecutive patients enrolled in the Stroke Thromboembolism Registry of Imaging and Pathology (STRIP) were included in this study. All patients underwent mechanical thrombectomy and retrieved clots were sent to a central core lab for processing. Histological analysis was performed using martius scarlet blue (MSB) staining, and quantification for red blood cells (RBCs), white blood cells (WBCs), fibrin and platelets was performed using Orbit Image Software. A Wilcoxon test was used for continuous variables and χ2 test for categorical variables. RESULTS: 1350 patients were included in this study. The overall rate of Thrombolysis In Cerebral Infarction (TICI) 2c/3 was 68%. 501 patients received tissue plasminogen activator (tPA) (37%). 267 patients (20%) had a large artery atherosclerosis (LAA) source, 662 (49%) a cardioembolic (CE) source, 301 (22%) were cryptogenic, and the remainder had other identifiable sources including hypercoagulable state or dissection. LAA thrombi had a higher mean RBC density (46±23% vs 42±22%, p=0.01) and a lower platelet density (24±18% vs 27±18%, p=0.03) than CE thrombi. Clots from dissection patients had the highest mean RBC density (50±24%) while clots from patients with a hypercoagulable state had the lowest mean RBC density (26±21%). CONCLUSIONS: Our study found statistically significant but clinically insignificant differences between clots of CE and LAA etiologies. Future studies should emphasize molecular, proteomic and immunohistochemical characteristics to determine links between clot composition and etiology.

Effective tranexamic acid concentration for 95% inhibition of tissue-type plasminogen activator-induced hyperfibrinolysis in full-term pregnant women: a prospective interventional study.

Postpartum haemorrhage is the leading cause of maternal mortality and morbidity worldwide. Tranexamic acid (TXA) has been shown to reduce blood loss and blood product transfusion requirements. Despite clinical evidence, further studies are needed to better define the pharmacokinetic and pharmacodynamic characteristics of TXA in pregnant women. The objective of our prospective observational ex-vivo study was to define the effective TXA concentration required to inhibit 95% (EC95) of tissue-type plasminogen activator (t-PA)-induced fibrinolysis in full-term pregnant women. Hyperfibrinolysis was induced by adding supraphysiologic concentration of t-PA to blood samples obtained from 30 full-term pregnant women and 10 healthy nonpregnant female volunteers. Increasing TXA concentrations (0--40 µg/ml) were then spiked into the blood samples and inhibition of fibrinolysis was assessed using the lysis index at 30 min of the ROTEM measured on EXTEM and NATEM tests. Effective TXA concentrations required to achieve EC95 were extrapolated using nonlinear regression. EC95 were compared between groups using an extra sum-of-squares F test. EC95 in pregnant women was 14.7 µg/ml (95% CI 12.4--17.5 µg/ml) on EXTEM and 11.2 µg/ml (95% CI 8.3--15.1 µg/ml) on NATEM tests. These values were significantly higher than those obtained in volunteers: 8.7 µg/ml (95% CI 5.5--13.9 µg/ml) and 6.8 µg/ml (95% CI 5.3--8.8 µg/ml), respectively (both P < 0.001). Our results suggest a higher fibrinolytic potential in pregnant women compared with nonpregnant women.

Plasma tissue plasminogen activator and plasminogen activator inhibitor-1 in hospitalized COVID-19 patients.

Patients with coronavirus disease-19 (COVID-19) are at high risk for thrombotic arterial and venous occlusions. However, bleeding complications have also been observed in some patients. Understanding the balance between coagulation and fibrinolysis will help inform optimal approaches to thrombosis prophylaxis and potential utility of fibrinolytic-targeted therapies. 118 hospitalized COVID-19 patients and 30 healthy controls were included in the study. We measured plasma antigen levels of tissue-type plasminogen activator (tPA) and plasminogen activator inhibitor-1 (PAI-1) and performed spontaneous clot-lysis assays. We found markedly elevated tPA and PAI-1 levels in patients hospitalized with COVID-19. Both factors demonstrated strong correlations with neutrophil counts and markers of neutrophil activation. High levels of tPA and PAI-1 were associated with worse respiratory status. High levels of tPA, in particular, were strongly correlated with mortality and a significant enhancement in spontaneous ex vivo clot-lysis. While both tPA and PAI-1 are elevated among COVID-19 patients, extremely high levels of tPA enhance spontaneous fibrinolysis and are significantly associated with mortality in some patients. These data indicate that fibrinolytic homeostasis in COVID-19 is complex with a subset of patients expressing a balance of factors that may favor fibrinolysis. Further study of tPA as a biomarker is warranted.

Tranexamic acid rapidly inhibits fibrinolysis, yet transiently enhances plasmin generation in vivo.

Tranexamic acid (TXA) is a lysine analogue that inhibits plasmin generation and has been used for decades as an antifibrinolytic agent to reduce bleeding. Recent reports have indicated that TXA can paradoxically promote plasmin generation. Blood was obtained from 41 cardiac surgical patients randomly assigned to TXA or placebo before start of surgery (preOP), at the end of surgery (EOS), then again on postoperative day 1 (POD-1) as well as POD-3. Plasma levels of tissue-type plasminogen activator (t-PA), urokinase (u-PA), the plasmin-antiplasmin (PAP) complex, as well as t-PA and u-PA-induced clot lysis assays were then determined. Clot lysis and PAP complex levels were also assessed in healthy volunteers before and at various time points after taking 1 g TXA orally. Surgery induced an increase in circulating t-PA, yet not u-PA at EOS. t-PA levels were unaffected by TXA; however, u-PA levels were significantly reduced in patients on POD-3. t-PA and u-PA-induced clot lysis were both inhibited in plasma from TXA-treated patients. In contrast, PAP complex formation, representing plasmin generation, was unexpectedly enhanced in the plasma of patients administered TXA at the EOS time point. In healthy volunteers, oral TXA effectively blocked fibrinolysis within 30 min and blockade was sustained for 8 h. However, TXA also increased PAP levels in volunteers 4 h after administration. Our findings demonstrate that TXA can actually augment PAP complex formation, consistent with an increase in plasmin generation in vivo despite the fact that it blocks fibrinolysis within 30 min. This may have unanticipated consequences in vivo.

Tissue Plasminogen Activator Levels and Risk of Breast Cancer in a Case-Cohort Study on Italian Women: Results from the Moli-sani Study.

BACKGROUND: Elevated levels of key enzymes of the fibrinolytic system, such as tissue plasminogen activator (tPA), are reported as predictors of poor outcome in cancer patients. Limited information is available about their potential predictive value for breast cancer (BC) risk in the general population. AIM: We examined the association of tPA levels with BC risk in a case-cohort study including women from the prospective Moli-sani cohort. METHODS: A sample of 710 women (mean age: 54.6 ± 12.1 years) was selected as a subcohort and compared with 84 BC cases, in a median follow-up of 4.2 years. Incident cases of BC were validated through medical records. tPA plasma levels were measured using an enzyme-linked immunosorbent assay kit. Hazard ratio (HR) and 95% confidence interval (CI), adjusted for relevant covariates, were estimated by a Cox regression model using the Prentice method. RESULTS: Compared with the lowest quartile (<4.9 ng/mL), women in the highest quartile of tPA (>11.2 ng/mL) had increased risk of BC (HRIVvsI: 2.20, 95% CI: 1.13-4.28) after adjusted for age, smoking, education, menopause, and residence. Further adjustment for biochemical markers did not modify this association. The risk of BC increased by 34% for each increase in 1 standard deviation of log-transformed tPA levels (p = 0.046). Elevated levels of tPA were associated mainly with estrogen-receptor-positive BC (2.08, 95% CI: 1.18-3.66). CONCLUSION: Higher levels of tPA, reported to predict cardiovascular risk, are a potential biomarker for BC risk, supporting the hypothesis of a "common soil" linking the pathogenic mechanisms of hormone-dependent tumors and cardiovascular disease.

Effects of Blood Components and Whole Blood in a Model of Severe Trauma-Induced Coagulopathy.

BACKGROUND: Plasma resuscitation ameliorates hyperfibrinolysis (HF) and trauma-induced coagulopathy (TIC). However, the use of other blood components to reduce HF has not been evaluated. Therefore, our aim was to determine the effect of individual blood components and whole blood (WB) on an in vitro model of severe HF/TIC. METHODS: A "TIC" solution was made with 1:1 dilution of WB with saline and exacerbated with tissue plasminogen activator (tPA). Components were added in proportions equivalent to the thromboelastography (TEG) based goal-directed resuscitation used at our institution. Whole blood was added at proportions equal to what has been transfused in injured patients. Samples (n = 9) underwent citrated native and tPA-challenge (75 ng/mL) TEG with analysis of R-time, angle, MA, and LY30. Statistical analyses were completed employing the nonparametric Kruskal-Wallis and Dunn's multiple comparisons tests. RESULTS: TIC solution, when compared to control, had a decrease in clot strength (MA 41 mm versus 51.5 mm, P < 0.01). The addition of tPA resulted in a severe coagulopathy (MA 24.5 mm versus 41 mm and LY30 52.8% versus 2.4%, P < 0.03 for all). The addition of 4U of WB improved clot strength compared to TIC + tPA (P = 0.03). No individual blood component resulted in improved fibrinolysis (P > 0.7). Cryoprecipitate improved R-time (7.5 versus 11.9 min, P < 0.01), angle (56.8 versus 30.2°) and MA (49 mm versus 36.25 mm), while platelets improved MA (44 mm versus 36.25 mm) compared to TIC + tPA (P < 0.03 for all). CONCLUSIONS: No single blood component or volume of whole blood led to attenuation of tPA-mediated fibrinolysis in an in vitro model of TIC. Cryoprecipitate was the most effective at improving coagulation function.

HSF1 Alleviates Microthrombosis and Multiple Organ Dysfunction in Mice with Sepsis by Upregulating the Transcription of Tissue-Type Plasminogen Activator.

Sepsis is a life-threatening complication of infection closely associated with coagulation abnormalities. Heat shock factor 1 (HSF1) is an important transcription factor involved in many biological processes, but its regulatory role in blood coagulation remained unclear. We generated a sepsis model in HSF1-knockout mice to evaluate the role of HSF1 in microthrombosis and multiple organ dysfunction. Compared with septic wild-type mice, septic HSF1-knockout mice exhibited a greater degree of lung, liver, and kidney tissue damage, increased fibrin/: fibrinogen deposition in the lungs and kidneys, and increased coagulation activity. RNA-seq analysis revealed that tissue-type plasminogen activator (t-PA) was upregulated in the lung tissues of septic mice, and the level of t-PA was significantly lower in HSF1-knockout mice than in wild-type mice in sepsis. The effects of HSF1 on t-PA expression were further validated in HSF1-knockout mice with sepsis and in vitro in mouse brain microvascular endothelial cells using HSF1 RNA interference or overexpression under lipopolysaccharide stimulation. Bioinformatics analysis, combined with electromobility shift and luciferase reporter assays, indicated that HSF1 directly upregulated t-PA at the transcriptional level. Our results reveal, for the first time, that HSF1 suppresses coagulation activity and microthrombosis by directly upregulating t-PA, thereby exerting protective effects against multiple organ dysfunction in sepsis.