Tissue Plasminogen Activator Research Articles

Surgical Treatment of Hemorrhagic Complications of Age-Related Macular Degeneration, Predictive Factors and Outcomes

Abstract Purpose The objective of this study was to evaluate the functional and clinical outcome of submacular hemorrhage in age-related macular degeneration (ARMD) using pneumatic displacement with intravitreal expansile gas by 23Gauge pars plana vitrectomy with subretinal injection of recombinant tissue plasminogen activator (rtPA) 50 mg in 0.1 ml. Patients and Methods Retrospective interventional case series of 58 pseudophakic patients, who underwent surgical treatment with inclusion criteria: subretinal, subretinal pigment epithelium (subRPE), or combined central hemorrhage associated with ARMD, 23 Gauge pars plana vitrectomy using rtPA sulfur hexafluoride (SF6 20%). Medical records were reviewed for logMAR best corrected visual acuity (BCVA), clinical findings, complications, and medical history up to 6 months after surgery. Results Patients were classified with small hemorrhage up to 2 × 2 papillary diameter (PD) in 32 eyes, moderate hemorrhage (up to 4 × 4PD, to the arcades) in 19 eyes and massive hemorrhage (from 5 × 5PD hemorrhage through the arcades to the periphery) in 7 eyes. Improvement of average postoperative BCVA was the best in the group with moderate extension of hemorrhage, 1.58 logMAR preoperative to 1.14 logMAR postoperative. Regarding the association between the hemorrhage category and clinical outcome, there was a significant positive association between the hemorrhage size before the operation and the scored clinical outcome. Conclusion Anticoagulants are associated with massive hemorrhage and, at the same time, with better postoperative BCVA than massive hemorrhage without total anticoagulant treatment.

Fibrinolytic activity in infants undergoing cardiac surgery on cardiopulmonary bypass with routine tranexamic acid: A prospective cohort substudy within the FIBrinogen CONcentrate randomised control trial.

Fibrinolytic activity contributes to bleeding after cardiopulmonary bypass (CPB). Our objectives were, in a group of infants undergoing cardiac surgery with CPB: to document the extent of peri-operative fibrinolysis using rotational thromboelastometry (ROTEM) and standard biomarkers; to compare the agreement between these fibrinolytic measures; to assess whether fibrinolytic activity is associated with early postoperative mediastinal bleeding and assess whether supplementation with fibrinogen concentrate affected fibrinolysis. Prospective cohort, mechanistic substudy, nested within the FIBrinogen CONcentrate (FIBCON) randomised controlled trial. Single centre, tertiary paediatric cardiac surgery and paediatric intensive care units. Ninety infants (median age 6.3 months) undergoing cardiac surgery, who all received routine intra-operative tranexamic acid. The infants were randomised to receive either an individualised dose of fibrinogen concentrate (n = 60) or placebo (n = 30) during CPB. We measured the ROTEM variable maximum clot lysis (ML), and fibrinolytic biomarkers including plasmin-antiplasmin (PAP) and tissue plasminogen activator antigen (tPA-Ag). Blood was sampled pre-CPB, on-CPB and post-CPB, and 4 h after PICU admission. tPA-Ag, PAP and ROTEM ML increased significantly after CPB despite the use of tranexamic acid. The two fibrinolytic biomarkers t-PA and PAP, correlated (P = 0.001) but neither correlated with ROTEM ML. Early postoperative blood loss was inversely associated with PAP levels. Each 100 μg l-1 rise in PAP was associated with a 7.9% reduction in mean blood loss. Fibrinogen concentrate supplementation as expected did not affect tPA-Ag but was temporally associated with an increase in PAP levels and a decrease in ROTEM fibrinolytic activity. Fibrinolysis is activated after paediatric cardiac CPB surgery as indicated by increased tPA-Ag and ROTEM ML. The substantial increase in tPA-Ag post-PICU admission is probably accompanied by a similar rise of plasminogen activator inhibitor 1 (PAI-1) as part of the acute phase response to surgery, thereby limiting clinical fibrinolysis. Supplementation of fibrinogen concentrate was associated with increased PAP activity and less clinical bleeding, consistent with the known role for fibrinogen in being a substrate for plasmin. ISCTRN:50553029, Eudract:2013-003532-68.

Abstract TP151: Optimizing Acute Stroke Care Through a Hub-and-Spoke Telestroke Network: Insights from a Large Cohort Analysis

Background: Efficient management of acute ischemic stroke is critical to reducing disability and mortality. The hub-and-spoke telestroke model has been developed to extend specialized stroke care to regions with limited resources, ensuring timely diagnosis and treatment. Objective: To evaluate the effectiveness of a large-scale hub-and-spoke telestroke network in delivering acute stroke care, focusing on the rates of thrombolysis and mechanical thrombectomy, treatment timelines, and patient outcomes. Methods: We conducted a retrospective analysis of 9,702 patients treated within a 38-hospital telestroke network from December 2014 to January 2018. Data collected included patient demographics, stroke characteristics, treatment interventions, and outcomes. Key measures included the proportion of patients receiving intravenous tissue plasminogen activator (IV tPA), mechanical thrombectomy, time from stroke onset to treatment, and rates of complications and discharge outcomes. Results: Of the 9,702 patients included, 83.1% were diagnosed with a true stroke, and the mean NIHSS score on admission was 6.2. IV tPA was recommended for 16.3% of patients, with 61.7% receiving the treatment. Mechanical thrombectomy was performed in 2.3% of cases, with an average procedure duration of 46.2 minutes. The median time from stroke onset to IV tPA administration was 114.2 minutes. Hemorrhagic transformation occurred in 19.4% of patients who received thrombolysis, and the overall mortality rate was 17.4%. The average NIHSS score at discharge improved to 4.4, with 54.9% of patients discharged home. Conclusion: The hub-and-spoke telestroke network demonstrated significant efficacy in delivering timely, specialized stroke care across a large and diverse patient cohort. By reducing treatment delays and optimizing access to advanced interventions, this model has the potential to transform stroke care in underserved regions, reducing both mortality and long-term disability.

Photothrombolytics: A light-driven technology for the targeted lysis of thrombi

Occlusive blood clots remain a significant global health challenge and result in emergencies that are main causes of death and disability worldwide. Thrombolytic agents (including tissue plasminogen activator, tPA) are the only pharmacological means to dissolve blood clots. However, these drugs have modest efficacy and severe safety concerns persist. We have developed light-responsive tPA-loaded red blood cells (tPA-RBCsPhoto) to target thrombolytic activity at the site of a blood clot. Herein, we describe the use of light to control the release of tPA from engineered RBCs and the subsequent degradation of a blood clot ex vivo. Furthermore, we have employed this technology to restore blood flow to an occluded mouse artery in vivo using a targeted dose that is 25 times lower than conventional systemic tPA treatment.

Abstract TP401: Impact of tissue Plasminogen Activator on thrombus weight and composition.

Abstract TP401: Impact of tissue Plasminogen Activator on thrombus weight and composition.

Outcomes and safety of mechanical thrombectomy, alteplase, and conventional medical care in the treatment of acute M2 segment middle cerebral artery occlusion: a comparative study

BackgroundData on mechanical thrombectomy (MT) to treat M2 occlusions of the middle cerebral artery (MCA) are sparse. We report the outcome and safety of MT versus intravenous recombinant tissue plasminogen activator (IV rTPA) versus conventional medical treatment (CMT) of acute ischemic stroke (AIS) due to occlusion of the M2 segment of the MCA. This prospective longitudinal intervention study compared the outcomes and safety of MT, rTPA, and CMT in M2 occlusion AIS patients. National Institutes of Health Stroke Scale (NIHSS), modified Rankin scale (mRS), and recanalization rate assessed outcomes.Results74 AIS patients were recruited (23 MT, 23 rTPA, 28CMT). MT group had significantly higher admission NIHSS (p = 0.018) and mRS (p = 0.023) than rTPA. At 24 h, NIHSS improved more with MT and rTPA than CMT (p < 0.0001). At 3 months, mRS were better with MT and rTPA versus CMT (p < 0.0001). Successful recanalization occurred in 73.9% of the MT group. 69% of the MT group required stent retrieval plus aspiration thrombectomy, and 60.9% required ≥ 3 trials, but outcomes did not differ by technique or number of trials. A good outcome (mRS 0–2) at 3 months was achieved in 69.6% MT versus 65.2% rTPA versus 7.1% CMT (p < 0.0001). Symptomatic intracranial hemorrhage (sICH) rates were slightly, but insignificantly, higher with CMT. Mortality did not significantly differ between groups.ConclusionsFor M2 occlusions, MT and rTPA achieved better early and 3-month outcomes than CMT; however, MT was not superior to rTPA. MT of M2 is feasible and effective, with a lower hemorrhage rate than rTPA and CMT.Trial registration: This study was prospectively registered in the clinical trial with ClinicalTrials.gov ID (NCT05091320). The link: https://clinicaltrials.gov/study/NCT05091320

Rhegmatogenous Retinal Detachment Following Vitrectomy and Subretinal Tissue Plasminogen Activator for Submacular Hemorrhage.

To investigate the incidence and outcomes of rhegmatogenous retinal detachment (RRD) occurring after pars plana vitrectomy (PPV) and subretinal tissue plasminogen activator (tPA) for submacular hemorrhage (SMH). Charts were reviewed between April 1, 2014 and September 1, 2023 for eyes that underwent PPV/subretinal tPA for SMH. Out of 167 eyes, 15 (9%) eyes developed RRD with macular detachment in 12 (80%) and proliferative vitreoretinopathy (PVR) in 9 eyes (60%). The median (interquartile range, IQR) time from PPV/subretinal tPA until RRD diagnosis was 41 (22-81) days. Single-surgery anatomic success was achieved in 11 eyes (85%) at three months and 9 eyes (70%) at the final visit. Four eyes (27%) developed redetachment and three underwent a median of two additional repairs. The final anatomic success rate for reattachment was 92% (12/13). The median (IQR) logMAR [Snellen] visual acuity at the preoperative visit following SMH was 2 (2-2.3) [20/2000], which worsened to 2.3 (2.2-2.7) [20/4000] at the time of RRD diagnosis (P=0.01) and plateaued by the final visit to 2.3 (2-2.7) [20/4000] (P=0.15). Postoperative RRD occurred in nearly 1 in 10 eyes after PPV/subretinal tPA for SMH and was associated with a relatively high rate of PVR.

Assessment of retinal pigment epithelium tears in eyes with submacular hemorrhage secondary to age-related macular degeneration

To assess retinal pigment epithelium (RPE) tears in eyes which underwent pars plana vitrectomy (PPV) for submacular hemorrhage (SMH) secondary to age-related macular degeneration and to investigate the prognostic factors of visual outcomes. This study was a retrospective, observational case series that included 24 eyes of 24 patients who underwent PPV with subretinal tissue plasminogen activator and air for SMH. RPE tears were investigated using spectral-domain or swept-source optical coherence tomography images with raster scan, combined confocal scanning laser ophthalmoscope near-infrared images and color fundus photographs. Multiple regression analysis was performed to identify the predictors of visual outcome at month 3 and 6 after surgery. In 21 eyes out of 24 eyes (87.5%), RPE tear was detected in the posterior pole. Eight eyes (33.3%) had large RPE tears ( ≧ 1 disc diameter (DD)). Out of the 8 eyes, 5 eyes progressed fibrotic scars within 3 months despite successful SMH removal and showed decrease in their visual acuity (VA). The ratio of eyes with large RPE tears ( ≧ 1DD) were significantly higher in eyes which had undergone anti-VEGF therapy within 3 months than in treatment-naïve eyes (71.4% vs. 25.0%, p = 0.048). The multiple regression analysis revealed that a small RPE tear (< 1DD) and treatment-naïve condition were associated with better VA at month 3 and 6. SMH within 3 months after anti-VEGF therapy might be accompanied by a large RPE tear. An RPE tear which was smaller than 1DD and treatment-naïve condition were associated with better prognosis.

Assessment of Reperfusion Efficacy of Altelyse Versus Actilyse in Patients with Acute Myocardial Infarction: A Phase 3, Randomized, Double-Blinded, Non-inferiority Clinical Trial.

Primary percutaneous coronary intervention (PPCI) and fibrinolytic or thrombolytic therapy are common treatments for ST-elevation myocardial infarction (STEMI). Primary percutaneous coronary intervention is more effective than thrombolytic therapy, but fibrinolytic therapy is still a preferable option for patients with limited access to healthcare. Alteplase is a tissue plasminogen activator (tPA) used to treat acute myocardial infarction, acute ischemic stroke, and pulmonary embolism. This study aims to compare the efficacy and safety of Altelyse (bio-similar Alteplase, Arena Life Science Company, Tehran, IRAN) versus the brand name Actilyse® (Boehringer Ingelheim, GERMANY) in patients with STEMI. In this phase 3, double-blind, randomized trial, we assigned patients with STEMI to receive Altelyse or Actilyse, an intravenous bolus of 15 mg followed by an infusion of 0.75 mg/kg over 30 min (with a maximum dose of 50 mg) and continued with 0.50 mg/kg over 60 min (with a maximum dose of 35 mg). The primary endpoint was total ST-segment resolution (STR) in all leads with ST-segment elevations after 90 min of receiving fibrinolytic therapy. A total of 153 STEMI patients received Actilyse (79 patients) or Altelyse (74 patients). The mean total STR in all leads with ST elevation after 90 min was -45.89 ± 32.92% and -37.11 ± 35.28% in the Altelyse and Actilyse groups, respectively (the mean difference [95% confidence interval]: -8.77 [-19.92, 2.36]; p-value for non-inferiority: 0.0004). Among patients with STEMI, Altelyse was non-inferior to Actilyse with respect to STR after 90 min. Trial Registration Number, Date: IRCT20190729044366N1, 2019-05-25.

Effect of IV Thrombolysis With Alteplase in Patients With Vessel Occlusion in the WAKE-UP Trial.

Data from randomized trials on the treatment effect of pure thrombolysis in patients with vessel occlusion are lacking. We examined data from a corresponding subsample of patients from the multicenter, randomized, placebo-controlled WAKE-UP trial to determine whether MRI-guided IV thrombolysis with alteplase in unknown-onset ischemic stroke benefits patients presenting with vessel occlusion. Patients with an acute ischemic lesion visible on MRI diffusion-weighted imaging but no marked parenchymal hyperintensity on fluid-attenuated inversion recovery images were randomized to treatment with IV alteplase or placebo. The primary end point was a favorable outcome defined by a modified Rankin Scale score of 0-1 at 90 days after stroke. We investigated the interaction between vessel status and treatment effect using an unconditional logistic regression model. Treatment effects (adjusted odds ratio [aOR]) and their 95% CI were compared in patients with and without any vessel occlusion (AVO) and large vessel occlusion (LVO). 185 patients (mean age 64.5 years, 46% female, median NIH Stroke Scale score 9, median time between last seen well and MRI 10.26 hours) received treatment and presented with an occlusion. 98 (20%) had LVO (defined as occlusion of the internal carotid artery, middle cerebral artery trunk, or combination). A favorable outcome was observed in 30 of 94 patients with AVO (31.9%) in the alteplase group and in 18 of 91 (19.8%) in the placebo group (aOR 2.04, 95% CI 1.00-4.18). In the subgroup of patients with LVO, a favorable outcome was observed in 16 of 53 (30.2%) in the alteplase group and in 7 of 44 (15.9%) in the placebo group (aOR 2.08, 95% CI 0.71-6.10). Treatment with alteplase was associated with higher odds of favorable outcomes with no heterogeneity of treatment effect between patients with AVO and patent vessel (p = 0.56), or between patients with and without LVO (p = 0.69). Although the WAKE-UP study was not powered to demonstrate treatment efficacy in patient subpopulations, this subgroup analysis points to a benefit of MRI-guided thrombolysis in patients with unknown-onset ischemic stroke, independent of vessel occlusion. Registered at ClinicalTrials.gov with unique identifier NCT01525290 (clinicaltrials.gov/study/NCT01525290). The study was first posted on February 2, 2012; the first patient was enrolled on September 24, 2012. This study provides Class II evidence that for patients with unknown-onset ischemic stroke with AVO, MRI-guided treatment with IV tissue plasminogen activator improves outcomes.

Dysregulated Clot Mechanics and Kinetics Impacted by Injury Severity, Predict Mortality After Trauma.

Introduction: Coagulopathy following traumatic injury impairs stable blood clot formation and exacerbates mortality from hemorrhage. Understanding how these alterations impact blood clot stability is critical to improving resuscitation. Furthermore, the incorporation of machine learning algorithms to assess clinical markers, coagulation assays and biochemical assays allows us to define the contributions of these factors to mortality. In this study, we aimed to quantify changes in clot formation and mechanics after traumatic injury and their correlation to mortality.Materials and Methods: Plasma was isolated from injured patients upon arrival to the emergency department prior to blood product administration, or procedural intervention. Coagulation kinetics and mechanics of healthy donors and patient plasma were compared with rheological, turbidity and thrombin generation assays. ELISA's were performed to determine tissue plasminogen activator (tPA) and D-dimer concentration. Recursive elimination with random forest models were used to assess the predictive strength of clinical and laboratory factors.Results: Sixty-three patients were included in the study. Median injury severity score (ISS) was 17, median age was 38 years, and mortality was 30%. Trauma patients exhibited reduced clot stiffness, increased fibrinolysis, and reduced thrombin generation compared to healthy donors. Deceased patients exhibited the greatest deviation from healthy levels. Fibrinogen, clot stiffness, D-dimer and tPA all demonstrated significant correlation to ISS. Machine-learning algorithms identified the importance of coagulation kinetics and clot structure on patient outcomes.Conclusions: Rheological markers of coagulopathy and biochemical factors are associated with injury severity and are highly predictive of mortality after trauma, providing evidence for integrated predictive models and therapeutic strategies.

Development of an attenuated glutamine synthetase (GS) selection system for the stable expression of tissue plasminogen activator in CHO-K1 cells

Chinese hamster ovary (CHO) cells represent the most common host system for the expression of high-quality recombinant proteins. The development of stable CHO cell lines used in industrial recombinant protein production often relies on dihydrofolate reductase (DHFR) and glutamine synthetase (GS) amplification systems. Conventional approaches to develop stable cell lines lead to heterogeneous cell populations. Consequently, it is desirable to adopt innovative strategies to increase the efficiency of clone selection to reduce the time and effort invested in the cell line development process. Attenuating the selection marker gene is an effective strategy for isolating high-producing cells. In this study, we evaluated the efficiency of an attenuated glutamine synthetase selection system for the expression of human tissue plasminogen activator (t-PA) in CHO cells. We introduced an AU-rich element (ARE) at the 3’UTR of the glutamine synthetase coding sequence and employed a weak promoter (mSV40) for the expression of this gene. Subsequently, we analyzed the effect of ARE on the GS RNA levels, and recombinant t-PA expression. Our results demonstrate that the use of ARE significantly enhances the detection of high expressing cells compared to the control. Additionally, the t-PA expression level in GS-ARE clones was approximately 900-fold greater than those without the ARE.

The tissue-plasminogen activator-challenged thromboelastography provides a comprehensive assessment of fibrinolysis in the severely injured.

Tissue-plasminogen activator-challenged thromboelastography (tPA-TEG) predicts massive transfusion and mortality better than conventional rapid thromboelastography (rTEG), with little concordance between their lysis values (LY30). We hypothesized that the main fibrinolytic inhibitors plasminogen activator inhibitor-1 (PAI-1) and α-2 antiplasmin (A2AP), as well as markers of fibrinolytic activation (plasmin-antiplasmin [PAP], tPA-PAI-1 complex, tPA activity), would correlate more strongly with tPA-TEG versus rTEG LY30 and may explain the recent findings of four distinct fibrinolytic phenotypes in trauma based on these two TEG methodologies. Adult trauma patients (n = 56) had tPA-TEG, rTEG, and plasma obtained on arrival to the emergency department with institutional review board approval. Plasminogen activator inhibitor-1 activity, A2AP, PAP, and tPA-PAI-1 complex as well as tPA activity were measured. Data were analyzed using Spearman's correlations and analysis of variance. The median age was 34 years, 75% were male, and the New Injury Severity Score was 14. Mortality was 25%, and 23% required a massive transfusion. There was a significant negative correlation between PAI-1 activity and A2AP with tPA-TEG LY30 (r = -0.77, p < 0.0001 and r = -0.62, p < 0.0001). There was a significant positive correlation between PAP complex and tPA-TEG LY30 (r = 0.74, p < 0.0001). There was no correlation between any fibrinolytic analyte and rTEG LY30. When stratified by phenotype, patients with hypofibrinolysis and nonpathologic fibrinolysis had higher active PAI-1 (p < 0.05) and A2AP levels (p < 0.05), lower PAP (p < 0.05), and tPA-PAI-1 complex (p < 0.05). Tissue-plasminogen activator activity was higher in hyperfibrinolysis relative to the other three groups (p < 0.05). Tissue-plasminogen activator-TEG LY30 more accurately reflects fibrinolysis phenotypes in trauma patients than conventional TEG methods. This provides an explanation for tPA-TEG's superior performance over rTEG in predicting clinical outcomes. Basic Science; N/A.

Effects of blood pressure lowering in patients treated with intravenous thrombolysis before endovascular thrombectomy.

The effects of blood pressure (BP) lowering in patients treated with intravenous tissue plasminogen activator (IV tPA) before endovascular thrombectomy (EVT) are unclear. This study aims to investigate whether intensive and conventional BP management affect outcomes differently, depending on IV tPA administration before EVT. In this subgroup analysis of the Outcome in Patients Treated with Intra-Arterial Thrombectomy-Optimal Blood Pressure Control (OPTIMAL-BP; ClinicalTrials.gov Identifier: NCT04205305) trial, patients were divided into groups based on IV tPA use before EVT. Clinical outcomes of intensive (systolic BP target <140 mm Hg) or conventional BP management (systolic BP target 140-180 mm Hg) were compared among group. The primary efficacy outcome was a favorable outcome at 3 months (modified Rankin Scale score of 0-2). Primary safety outcomes included symptomatic intracerebral hemorrhage (sICH) within 36 hours and stroke-related death within 3 months. Among the 302 patients, the IV tPA group included 98 (32.5%) and the non-IV tPA group comprised 204 subjects (67.5%). In the IV tPA group, intensive BP management significantly lowered the favorable outcome rate (intensive, 27.3% vs. conventional, 51.9%; adjusted odds ratio [aOR], 0.36; 95% confidence interval [CI], 0.13-0.93; p = 0.04). In the non-IV tPA group, the risk difference rate of favorable outcome was not significantly different between intensive and conventional BP management (44.1% vs. 55.9%; aOR, 0.62; 95% CI, 0.31-1.22; p = 0.17). Notably, the proportion of malignant cerebral edema within 36 hours in the IV tPA group was significantly higher in the intensive management group (18.2%) than in the conventional management group (1.9%; aOR, 10.72; 95% CI, 1.24-92.29; p = 0.03). sICH and mortality rates were not significantly different between intensive and conventional BP management in either study groups. Intensive BP management worsen 3-month functional outcomes after successful EVT without reducing sICH among patients who received IV tPA before EVT, indicating that BP lowering in this population should be cautious.

Development and validation of an explainable machine learning prediction model of hemorrhagic transformation after intravenous thrombolysis in stroke.

To develop and validate an explainable machine learning (ML) model predicting the risk of hemorrhagic transformation (HT) after intravenous thrombolysis. We retrospectively enrolled patients who received intravenous tissue plasminogen activator (IV-tPA) thrombolysis within 4.5 h after symptom onset to form the original modeling cohort. HT was defined as any hemorrhage on head CT scan completed within 48 h after IV-tPA administration. We utilized the Random Forest (RF), Multilayer Perceptron (MLP), Adaptive Boosting (AdaBoost), and Gaussian Naive Bayes (GauNB) algorithms to develop ML-HT models. The models' predictive performance was evaluated using confusion matrix (including accuracy, precision, recall, and F1 score), and discriminative analysis (area under the receiver-operating-characteristic curve, ROC-AUC) in the original cohort, followed by validation in an independent external cohort. The models' explainability was assessed using SHapley Additive exPlanations (SHAP) global feature plot, SHAP Summary Plot, and Partial Dependence Plot. A total of 1,007 patients were included in the original modeling cohort, with an HT incidence of 8.94%. The RF-based ML-HT model showed metrics of 0.874 (accuracy), 0.972 (precision), 0.890 (recall), 0.929 (F1 score); with ROC-AUC of 0.7847 in the original cohort and 0.7119 in the external validation cohort. The MLP model showed 0.878, 0.967, 0.989, 0.978, 0.7710, and 0.6768, respectively. The AdaBoost model showed 0.907, 0.967, 0.989, 0.978, 0.7798, and 0.6606, respectively. The GauNB model showed 0.848, 0.983, 0.598, 0.716, 0.6953, and 0.6289, respectively. The explainable analysis of the RF-based ML model indicated that the National Institute of Health Stroke Scale (NIHSS) score, age, platelet count, and atrial fibrillation were the primary determinants for HT following IV-tPA thrombolysis. The RF-based explainable ML model demonstrated promising predictive ability for estimating the risk of HT after IV-tPA thrombolysis and may have the potential to assist the clinical decision-making in emergency settings.

The interaction of tPA with NMDAR1 drives neuroinflammation and neurodegeneration in α-synuclein-mediated neurotoxicity

The thrombolytic protease tissue plasminogen activator (tPA) is expressed in the CNS, where it regulates diverse functions including neuronal plasticity, neuroinflammation, and blood-brain-barrier integrity. However, its role in different brain regions such as the substantia nigra (SN) is largely unexplored. In this study, we characterize tPA expression, activity, and localization in the SN using a combination of retrograde tracing and β-galactosidase tPA reporter mice. We further investigate tPA’s potential role in SN pathology in an α-synuclein mouse model of Parkinson’s disease (PD). To characterize the mechanism of tPA action in α-synuclein-mediated pathology in the SN and to identify possible therapeutic pathways, we performed RNA-seq analysis of the SN and used multiple transgenic mouse models. These included tPA deficient mice and two newly developed transgenic mice, a knock-in model expressing endogenous levels of proteolytically inactive tPA (tPA Ala-KI) and a second model overexpressing proteolytically inactive tPA (tPA Ala-BAC). Our findings show that striatal GABAergic neurons send tPA+ projections to dopaminergic (DA)-neurons in the SN and that tPA is released from SN-derived synaptosomes upon stimulation. We also found that tPA levels in the SN increased following α-synuclein overexpression. Importantly, tPA deficiency protects DA-neurons from degeneration, prevents behavioral deficits, and reduces microglia activation and T-cell infiltration induced by α-synuclein overexpression. RNA-seq analysis indicates that tPA in the SN is required for the upregulation of genes involved in the innate and adaptive immune responses induced by α-synuclein overexpression. Overexpression of α-synuclein in tPA Ala-KI mice, expressing only proteolytically inactive tPA, confirms that tPA-mediated neuroinflammation and neurodegeneration is independent of its proteolytic activity. Moreover, overexpression of proteolytically inactive tPA in tPA Ala-BAC mice leads to increased neuroinflammation and neurodegeneration compared to mice expressing normal levels of tPA, suggesting a tPA dose response. Finally, treatment of mice with glunomab, a neutralizing antibody that selectively blocks tPA binding to the N-methyl-D-aspartate receptor-1 (NMDAR1) without affecting NMDAR1 ion channel function, identifies the tPA interaction with NMDAR1 as necessary for tPA-mediated neuroinflammation and neurodegeneration in response to α-synuclein-mediated neurotoxicity. Thus, our data identifies a novel pathway that promotes DA-neuron degeneration and suggests a potential therapeutic intervention for PD targeting the tPA-NMDAR1 interaction.

Unravelling the impact of SARS-CoV-2 on hemostatic and complement systems: a systems immunology perspective.

The hemostatic system prevents and stops bleeding, maintaining circulatory integrity after injury. It directly interacts with the complement system, which is key to innate immunity. In coronavirus disease 2019 (COVID-19), dysregulation of the hemostatic and complement systems has been associated with several complications. To understand the essential balance between activation and regulation of these systems, a quantitative systems immunology model can be established. The dynamics of the components are examined under three distinct conditions: the disease state representing symptomatic COVID-19 state, an intervened disease state marked by reduced levels of regulators, and drug interventions including heparin, tranexamic acid, avdoralimab, garadacimab, and tocilizumab. Simulation results highlight key components affected, including thrombin, tissue plasminogen activator, plasmin, fibrin degradation products, interleukin 6 (IL-6), the IL-6 and IL-6R complex, and the terminal complement complex (C5b-9). We explored that the decreased levels of complement factor H and C1-inhibitor significantly elevate these components, whereas tissue factor pathway inhibitor and alpha-2-macroglobulin have more modest effects. Furthermore, our analysis reveals that drug interventions have a restorative impact on these factors. Notably, targeting thrombin and plasmin in the early stages of thrombosis and fibrinolysis can improve the overall system. Additionally, the regulation of C5b-9 could aid in lysing the virus and/or infected cells. In conclusion, this study explains the regulatory mechanisms of the hemostatic and complement systems and illustrates how the biopathway machinery sustains the balance between activation and inhibition. The knowledge that we have acquired could contribute to designing therapies that target the hemostatic and complement systems.

Enhancing Hemocompatibility in ECMO Systems With a Fibrinolytic Interactive Coating: in Vitro Evaluation of Blood Clot Lysis Using a 3D Microfluidic Model.

Blood-contacting medical devices, especially extracorporeal membrane oxygenators (ECMOs), are highly susceptible to surface-induced coagulation because of their extensive surface area. This can compromise device functionality and lead to life-threatening complications. High doses of anticoagulants, combined with anti-thrombogenic surface coatings, are typically employed to mitigate this risk, but such treatment can lead to hemorrhagic complications. Therefore, bioactive surface coatings that mimic endothelial blood regulation are needed. However, evaluating these coatings under realistic ECMO conditions is both expensive and challenging. This study utilizes microchannel devices to simulate ECMO fluid dynamics and assess the clot-lysis efficacy of a self-activating fibrinolytic coating system. The system uses antifouling polymer brushes combined with tissue plasminogen activator (tPA) to induce fibrinolysis at the surface. Here, tPA catalyzes the conversion of blood plasminogen into plasmin, which dissolves clots. This positive feedback loop enhances clot digestion under ECMO-like conditions. This findings demonstrate that this coating system can significantly improve the hemocompatibility of medical device surfaces.

Successful thrombolysis in an elderly patient with a large-scale hemispheric brain infarction

Currently, one of the primary methods of reperfusion in ischemic stroke is systemic thrombolytic therapy (TLT) using recombinant tissue plasminogen activators (rtPA). Despite TLT’s effectiveness demonstrated in several large multicenter randomized placebo-controlled clinical trials, the use of rtPA at standard dosages carries a high risk of hemorrhagic complications, especially in patients with certain aggravating factors. This article presents a clinical case of early thrombolysis in a patient with ischemic stroke, utilizing an individualized dosage of rtPA despite the presence of relative contraindications for reperfusion therapy.

Assessing the Emergency Medicine Specialists' Knowledge Regarding Thrombolytic Therapy in Ischemic Stroke Patients

Background: Stroke is a major health concern worldwide, and timely intervention is crucial for improving outcomes in ischemic stroke patients. Emergency specialists play a critical role in managing these patients, yet gaps in their knowledge of stroke symptoms, risk factors, and thrombolytic therapy can cause delays in treatment, ultimately impacting patient outcomes. Objectives: This study aimed to evaluate the knowledge of emergency medicine specialists in Tabriz, Iran, regarding stroke symptoms, risk factors, and therapeutic interventions, with a specific focus on thrombolytic therapy. Methods: A survey study was conducted with 30 emergency medicine specialists from hospitals in Tabriz, using a structured questionnaire for data collection. Participants were selected through simple random sampling. The questionnaire assessed knowledge of common stroke symptoms, risk factors, and management protocols, including the use of tissue plasminogen activator (tPA). The validity and reliability of the tool were established through expert review and a pilot study. Data were analyzed using descriptive statistics and Pearson correlation, with a significance level set at P &lt; 0.05. Results: The study revealed that participants had limited knowledge of stroke symptoms, with most identifying only 4 out of 10 common symptoms. While high blood pressure and heart disease were widely recognized as risk factors (100%), less common factors, such as stress and heredity, were poorly identified. Regarding management, 97% of participants were aware of tPA, but none correctly identified all three treatment strategies (tPA, aspirin, and surgery). Additionally, fewer than 60% of participants prioritized calling emergency medical services (EMS) as the first step in stroke management. Conclusions: The findings underscore significant gaps in emergency specialists' knowledge of stroke symptoms, risk factors, and management strategies, particularly concerning thrombolytic therapy. Targeted educational interventions are essential to enhance emergency medicine specialists' understanding of stroke care and improve patient outcomes.