Tissue-type Plasminogen Activator Research Articles

The development of nasal polyps involves early middle meatus mucous remodeling via TGF-β1 mediated PAI-1 reduction

ObjectiveOur study aimed to elucidate the effect of PAI-1 (Plasminogen Activator Inhibitor-1) and t-PA (Tissue-type Plasminogen Activator) in tissue remodeling in nasal polyps patients. MethodsSamples were streamed as early Nasal Polyps (eNP, n=10) and inferior tissue from the same patient, mature Nasal Polyps (mNP, n=14), and Control group (n=15), respectively. Immunohistochemistry and immunofluorescence were applied to detect localization. Quantitative Real-Time Polymerase Chain Reaction (qRT-PCR) and Western blot were used to measure different levels among three groups. The mNP tissue was cultured in vitro and treated with TGF-β1 (Transforming Growth Factor-beta 1) activator, TGF-β1 inhibitor (SB431542), and PAI-1 inhibitor (TM5275); then Western blot, qRT-PCR, and ELISA were used to assess changes. ResultsThe immunohistochemistry and immunofluorescence showed that PAI-1 expression decreased in eNP and mNP, mainly in epithelium and glands. The transcriptional expression and protein level of TGF-β1/t-PA/PAI-1/Collagen1 were lower in eNP than IT while mNP group demonstrated lower mRNA expression and protein level of TGF-β1/t-PA/PAI-1/Collagen1 than Control group. In mNP tissue culture in vitro, TGF-β1 activator elevated t-PA, PAI-1, and Collagen1 with higher release of PAI-1 and Collagen1 in supernatant, whereas SB431542 suppressed above reactions; TM5275 lowered transcriptional and protein level of Collagen1 in supernatant. ConclusionEarly Nasal polyps’ formation in middle meatus mucous is related with fibrillation system PAI-1/t-PA and tissue remodeling; moreover, nasal polyps’ development is regulated by TGF-β1-mediated PAI-1 reduction. Level of evidence3b.

Effect of Argatroban Plus Intravenous Alteplase vs Intravenous Alteplase Alone on Neurologic Function in Patients With Acute Ischemic Stroke

Previous studies suggested a benefit of argatroban plus alteplase (recombinant tissue-type plasminogen activator) in patients with acute ischemic stroke (AIS). However, robust evidence in trials with large sample sizes is lacking. To assess the efficacy of argatroban plus alteplase for AIS. This multicenter, open-label, blinded end point randomized clinical trial including 808 patients with AIS was conducted at 50 hospitals in China with enrollment from January 18, 2019, through October 30, 2021, and final follow-up on January 24, 2022. Eligible patients were randomly assigned within 4.5 hours of symptom onset to the argatroban plus alteplase group (n = 402), which received intravenous argatroban (100 μg/kg bolus over 3-5 minutes followed by an infusion of 1.0 μg/kg per minute for 48 hours) within 1 hour after alteplase (0.9 mg/kg; maximum dose, 90 mg; 10% administered as 1-minute bolus, remaining infused over 1 hour), or alteplase alone group (n = 415), which received intravenous alteplase alone. Both groups received guideline-based treatments. The primary end point was excellent functional outcome, defined as a modified Rankin Scale score (range, 0 [no symptoms] to 6 [death]) of 0 to 1 at 90 days. All end points had blinded assessment and were analyzed on a full analysis set. Among 817 eligible patients with AIS who were randomized (median [IQR] age, 65 [57-71] years; 238 [29.1%] women; median [IQR] National Institutes of Health Stroke Scale score, 9 [7-12]), 760 (93.0%) completed the trial. At 90 days, 210 of 329 participants (63.8%) in the argatroban plus alteplase group vs 238 of 367 (64.9%) in the alteplase alone group had an excellent functional outcome (risk difference, -1.0% [95% CI, -8.1% to 6.1%]; risk ratio, 0.98 [95% CI, 0.88-1.10]; P = .78). The percentages of participants with symptomatic intracranial hemorrhage, parenchymal hematoma type 2, and major systemic bleeding were 2.1% (8/383), 2.3% (9/383), and 0.3% (1/383), respectively, in the argatroban plus alteplase group and 1.8% (7/397), 2.5% (10/397), and 0.5% (2/397), respectively, in the alteplase alone group. Among patients with acute ischemic stroke, treatment with argatroban plus intravenous alteplase compared with alteplase alone did not result in a significantly greater likelihood of excellent functional outcome at 90 days. ClinicalTrials.gov Identifier: NCT03740958.

Blood tissue Plasminogen Activator (tPA) of liver origin contributes to neurovascular coupling involving brain endothelial N-Methyl-D-Aspartate (NMDA) receptors

BackgroundRegulation of cerebral blood flow (CBF) directly influence brain functions and dysfunctions and involves complex mechanisms, including neurovascular coupling (NVC). It was suggested that the serine protease tissue-type plasminogen activator (tPA) could control CNV induced by whisker stimulation in rodents, through its action on N-methyl-d-Aspartate receptors (NMDARs). However, the origin of tPA and the location and mechanism of its action on NMDARs in relation to CNV remained debated.MethodsHere, we answered these issues using tPANull mice, conditional deletions of either endothelial tPA (VECad-CreΔtPA) or endothelial GluN1 subunit of NMDARs (VECad-CreΔGluN1), parabioses between wild-type and tPANull mice, hydrodynamic transfection-induced deletion of liver tPA, hepatectomy and pharmacological approaches.ResultsWe thus demonstrate that physiological concentrations of vascular tPA, achieved by the bradykinin type 2 receptors-dependent production and release of tPA from liver endothelial cells, promote NVC, through a mechanism dependent on brain endothelial NMDARs.ConclusionsThese data highlight a new mechanism of regulation of NVC involving both endothelial tPA and NMDARs.

Rapid Activation of Neuroinflammation in Stroke: Plasma and Extracellular Vesicles Obtained on a Mobile Stroke Unit.

Neuroinflammation is ubiquitous in acute stroke and worsens outcome. However, the precise timing of the inflammatory response is unknown, hindering the design of acute anti-inflammatory therapeutic interventions. We sought to identify the onset of the neuroinflammatory cascade using a mobile stroke unit. The study is a proof-of-concept, cohort investigation of ultra-early blood- and extracellular vesicle-derived markers of neuroinflammation and outcome in acute stroke. Blood was obtained, prehospital, on an mobile stroke unit. Outcomes were biomarker concentrations, modified Rankin Scale score, and National Institutes of Health Stroke Scale score. Forty-one adults were analyzed, including 15 patients treated on the mobile stroke unit between August 2021 and April 2022, and 26 healthy controls to establish biomarker reference levels. Median patient age was 74 (range, 36-97) years, 60% were female, and 80% White. Ten (67%) were diagnosed as stroke, with 8 (53%) confirmed and 2 likely transient ischemic attack or stroke averted by thrombolysis; 5 were stroke mimics. For strokes, median initial National Institutes of Health Stroke Scale score was 11 (range, 4-19) and 6 (75%) received tPA (tissue-type plasminogen activator). Blood was obtained a median of 58 (range, 36-133) minutes after symptom onset. Within 36 minutes after stroke, plasma IL-6 (interleukin-6), neurofilament light chain, UCH-L1 (ubiquitin C-terminal hydrolase L1), and GFAP (glial fibrillary acidic protein) were elevated by as much as 10 times normal. In EVs, MMP-9 (matrix metalloproteinase-9), CXCL4 (chemokine (C-X-C motif) ligand 4), CRP (C-reactive protein), IL-6, OPN (osteopontin), and PECAM1 (platelet and endothelial cell adhesion molecule 1) were elevated. Inflammatory markers increased rapidly in the first 2 hours and continued rising for 24 hours. The neuroinflammatory cascade was found to be activated within 36 to 133 minutes after stroke and progresses rapidly. This is earlier than observed previously in humans and suggests injury from neuroinflammation occurs faster than had been surmised. These findings could inform development of acute immunomodulatory stroke therapies and lead to new diagnostic tools and improved outcomes.

Golden Hour Treatment With tPA (Tissue-Type Plasminogen Activator) in the BEST-MSU Study.

Treatment of patients with acute ischemic stroke on mobile stroke units (MSUs) improves outcomes compared with management by standard emergency medical services ambulances and is associated with more patients treated with intravenous tPA (tissue-type plasminogen activator) in the first golden hour after last known normal. We explored the predictors and outcomes of first-hour treatment (FHT) compared with later treatment in an alternating-week cluster-controlled trial of MSUs. We analyzed all patients treated with intravenous tPA in the BEST-MSU Study (Benefits of Stroke Treatment Delivered by a Mobile Stroke Unit Compared to Standard Management by Emergency Medical Services). After stratifying by treatment timeframe, we identified factors associated with FHT. We performed adjusted analyses of the association between FHT and clinical outcome and modeled the shape of the relationship between last known normal-to-treatment time and excellent outcome. Among 941 tPA-treated patients, 206 (21.8%) had lytic started within 60 minutes. Treatment on the MSU, older age, male sex, alert by 911, faster arrival on-scene and imaging, more severe stroke, atrial fibrillation, and absence of heart failure and pretreatment antihypertensive treatment were associated with FHT. Compared with later treatment, FHT was associated with higher adjusted odds ratio for 90-day modified Rankin Scale score of 0 to 1 (odds ratio, 1.87 [95% CI, 1.25-2.84]; P=0.003). Among FHT patients, 68% achieved a 90-day modified Rankin Scale of 0 or 1 or returned to their baseline status. FHT was not associated with higher risk of hemorrhage and was associated with reduced risk of treating neurovascular mimics. FHT almost doubles the odds of excellent clinical outcome without increased risk compared with later treatment, which supports the use of MSUs.

Abstract TP9: Examining Predictors Of Functional 90-day Outcome Among Stroke Patients With Active Cancer Receiving Endovascular Therapy

Introduction: Intraarterial therapy (IAT) is the standard of care for all AIS patients, even those with active cancer. However, there is little information on the characteristics that may contribute to a functional 90-day modified Rankin scale (mRS 0-2) score for AIS patients with active cancer undergoing IAT. Methods: This retrospective study included patients (age ≥ 18) admitted from 07/18-10/20 with AIS and were treated by IAT. AIS patients with large artery occlusion who had active cancer were identified. Baseline characteristics and outcomes were evaluated to determine predictors of a functional outcome at 90 days. Outcomes were also compared to those without active cancer during the same period. The receiver operating characteristic area under the curve (AUC) was used to determine optimal admission national institutes of health scores (NIHSS) to obtain a 90-day mRS of 0-2. Results: Of the 453 patients who received IAT, 12% had active cancer. Overall, patients were a majority male (50%), a median of 70 (60-81) years of age and had an admission NIHSS of 14 (7-20). Compared to patients without cancer, patients with cancer experienced significantly more thromboembolic events during their hospital stay (40% vs. 11%, p<0.001), but functional outcomes at 90-days were not different between groups. In active cancer patients, an admission NIHSS cut-off of 8.2 (AUC:0.72 (confidence interval (CI): 0.58-0.86), p=0.001) indicating strong fit, and experiencing less thromboembolic events, were significantly associated with functional independency at 90 days. However, the admission NIHSS cut-off for patients without cancer for predicting a functional outcome was 10.5 (AUC: 0.66 (CI: 0.60-.71), p<0.001), indicating moderate fit. Receiving intravenous tissue type plasminogen activator (IV-tPA) and successful reperfusion were other significant predictors of a functional outcome for non-cancer patients. Conclusions: In our population, using an NIHSS cut-off of 8.2 for patients with active cancer in determining who should receive IAT may increase the probability of a favorable 90-day outcome. An admission NIHSS of 10.5 was moderately associated with functional outcome at 90 days, in addition to successful reperfusion and receiving IV-tPA in non-cancer patients.

Abstract WMP90: Is Endovascular Thrombectomy More Effective Than IV-tPA For Distal Vessel Occlusions? Propensity Score-matched Analysis From K-net Registry

Background and Purpose: The benefit of endovascular thrombectomy (EVT) for acute ischemic stroke due to primary distal vessel occlusions is unclear. We assessed whether outcome of acute ischemic stroke patients treated with EVT for primary distal vessel occlusions was better than intravenous tissue-type plasminogen activator (IV-tPA) alone. Materials and Methods: We investigated data from K-NET Registry, which is a prospective, multicenter, observational registry of acute ischemic stroke patients treated with EVT or IV t-PA in Kanagawa, Japan. We evaluated the patients who had primally distal vessel occlusion and were treated with EVT (with or without IV-tPA) or IV tPA alone. Distal vessel occlusion was defined as middle cerebral artery M2-M3, anterior cerebral artery or posterior cerebral artery occlusion. Propensity score-matched analysis was conducted to compare outcomes between EVT and IV-tPA alone. Primary outcome was good outcome at 90 days, defined as mRS of 0 to 2 or not worsening compared to pre-stroke mRS. Safety outcome was the occurrence of all hemorrhage and symptomatic hemorrhage. Results: 703 patients with distal vessel occlusion (MCA M2, 436 cases, M3, 167 cases, ACA 48 cases, PCA 52 cases) were included in this study. 461 cases were treated with EVT and 242 were IV-tPA alone. Propensity-score matching paired 110 patients with EVT and 110 patients with IV-tPA. There were no significant differences in good clinical outcome (EVT 65.4%, IV-tAP 60.0%), all hemorrhage (EVT 15.4%, IV-tAP 11.8%) and symptomatic hemorrhage (EVT 4.5%, IV-tAP 1.8%). Dividing EVT group into EVT with IV-tPA and EVT alone, there were no significant differences in outcomes compared to IV-tPA alone. Conclusions: The benefit of EVT for acute primary distal vessel occlusions was similar as IV-tPA alone. Although IV-tPA is a first line treatment for primary distal vessel occlusions, EVT is a feasible treatment for patients who have contraindication to IV-tPA.

Abstract WP162: Primary Results Of Mechanical Thrombectomy For Acute Ischemic Stroke In Clinical Practice: K-net Registry

Background: Endovascular treatment (EVT) for acute large vessel occlusion has been found to be effective in several randomized controlled trials. We conducted a prospective cohort study to evaluate the real-world efficacy of EVT in patients with acute ischemic stroke in a metropolitan area with a high population density and a large number of comprehensive stroke centers. Methods: We analyzed the Kanagawa Intravenous and Endovascular Treatment of Acute Ischemic Stroke registry, a prospective, multicenter observational study of patients treated by EVT and/or intravenous tissue-type plasminogen activator (tPA), in Kanagawa, Japan. Of the 2488 patients enrolled from January 2018 to June 2020, 1764 patients treated with EVT were included. The primary outcome was a good outcome, which was defined as a modified Rankin Scale (mRS) of 0 to 2 at 90 days. Secondary analysis included predicting a good outcome using multivariate logistic regression analysis. Results: The median age was 77 years and the median National Institute of Health Stroke Scale (NIHSS) score was 18. Pretreatment mRS score 0-2 was 87%, and direct transport was 92%. The rate of occlusion in anterior circulation was 90.3%. Successful recanalization was observed in 88.7%. The median time from onset to recanalization was 193 minutes. Good outcomes at 90 days were 43.3% in anterior circulation and 41.9% in posterior circulation. Furthermore, 49.3% of patients with anterior circulation obstruction who had pre-stroke mRS 0-2 had good outcome, which was higher than the HERMES trial. Overall mortality was 12.6%. Significant predictors for a good outcome were: age, male, direct transfer, NIHSS score, Alberta Stroke Program Early Computed Tomography Score, intravenous tPA, and successful recanalization. Conclusions: EVT in routine clinical use in a metropolitan area showed comparable good outcomes and lower mortality compared to previous registries and RCTs, despite the high proportion of patients with older age, pretreatment mRS score of > 2, posterior circulation occlusion, and higher NIHSS. Those results may have been associated with more direct transport and faster onset-to-recanalization times.

Preventative effects of the albumin nano tissue-type plasminogen activator gene plasmid ultrasound microbubble carrier system on thrombosis after cardiac valve replacement

Mechanical valve replacement is a new method for treating rheumatic heart valve disease. However, patients require long-term anticoagulation therapy after surgery, thus reducing their use of anticoagulants, making the prevention of postoperative thrombosis of great research interest. We examined the potential preventative effects of the albumin nano tissue plasminogen activator (tPA) gene plasmid ultrasound microbubble carrier system on thrombosis. The average particle size of the nano tPA gene plasmid was 131.8 nm, the surface zeta potential was 30.65±40.34 mV, and the encapsulation efficiency was 76.56%, all meeting experimental requirements. One month after gene integration, the tPA content of group B had increased beyond pre-integration levels and above post-integration levels of group A. After valve replacement operations, the venous blood D-Dimer (D-D) content of group B increased significantly, whereas the venous blood D-D content of group A decreased. In addition, at 1, 2, and 4 weeks after operation, the venous blood D-D content of group B was greater than that of group A. These results suggest that the prepared albumin nano tPA gene plasmid ultrasound microbubble vector system can prevent thrombosis after heart valve replacement.

Nationally Certified Stroke Centers Outperform Self-Attested Stroke Centers in the Florida Stroke Registry.

The Florida Stroke Act, signed into law in 2004, set criteria for Comprehensive Stroke Centers (CSC). For a set time period, Florida hospitals were permitted to either receive national certification (NC) or could self-attest (SA) as fulfilling CSC criteria. The aim of this project was to evaluate the quality of ischemic stroke care in NC versus SA stroke centers in Florida, using well-known, guideline-driven ischemic stroke outcome metrics. A total of 37 CSCs (74% of Florida CSCs) in the Florida Stroke Registry from January 2013 through December 2018 were analyzed, including 19 SA CSCs and 18 NC (13 CSCs and 5 Thrombectomy-Capable Stroke Center). Hospital- and patient-level characteristics and stroke metrics were evaluated, adjusting for demographics, medical comorbidities, and stroke severity. A total of 78 424 acute ischemic stroke cases, 36 089 from SA CSCs and 42 335 from NC CSC/Thrombectomy-Capable Stroke Centers were analyzed. NC centers had older patients (73 [61-83] versus 71 [60-81]; P<0.001) with more severe strokes (median National Institutes of Health Stroke Scale score of 5 versus 4; P<0.001). NC had higher intravenous tissue-type plasminogen activator utilization (15% versus 13%; P<0.001), endovascular treatment (10% versus 7%; P<0.001) and faster median door-to-computed tomography (23 minutes [11-73] versus 31 [12-78]; P<0.001), door-to-needle (37 minutes [26-50] versus 45 [34-58]; P<0.001) and door-to-puncture times (77 minutes [50-113] versus 93 [62-140]; P<0.001). In adjusted analysis, patients arriving to NC hospitals by 3 hours were more likely to get intravenous tissue-type plasminogen activator in the 3- to 4.5-hour window (adjusted odds ratio, 1.87 [95% CI, 1.30-2.68]; P=0.001) and more likely to be treated with intravenous tissue-type plasminogen activator within 45 minutes (adjusted odds ratio, 1.61 [95% CI, 1.04-2.50]; P=0.04) compared with SA CSCs. Among Florida-Stroke Registry CSCs, acute ischemic stroke performance and treatment measures at NC centers are superior to SA CSCs. These findings have implications for stroke systems of care in Florida and support legislation updates requiring NC and removal of SA claims.

Modulations of the neuronal trafficking of tissue-type plasminogen activator (tPA) influences glutamate release

The discovery of the neuronal expression of the serine protease tissue-type plasminogen activator (tPA) has opened new avenues of research, with important implications in the physiopathology of the central nervous system. For example, the interaction of tPA with synaptic receptors (NMDAR, LRP1, Annexin II, and EGFR) and its role in the maturation of BDNF have been reported to influence synaptic plasticity and neuronal survival. However, the mechanisms regulating the neuronal trafficking of tPA are unknown. Here, using high-resolution live cell imaging and a panel of innovative genetic approaches, we first unmasked the dynamic characteristics of the dendritic and axonal trafficking of tPA-containing vesicles under different paradigms of neuronal activation or inhibition. We then report a constitutive exocytosis of tPA- and VAMP2-positive vesicles, dramatically increased in conditions of neuronal activation, with a pattern which was mainly dendritic and thus post-synaptic. We also observed that the synaptic release of tPA led to an increase of the exocytosis of VGlut1 positive vesicles containing glutamate. Finally, we described alterations of the trafficking and exocytosis of neuronal tPA in cultured cortical neurons prepared from tau-22 transgenic mice (a preclinical model of Alzheimer’s disease (AD)). Altogether, these data provide new insights about the neuronal trafficking of tPA, contributing to a better knowledge of the tPA-dependent brain functions and dysfunctions.

Direct Mechanical Thrombectomy Versus Prior Bridging Intravenous Thrombolysis in Acute Ischemic Stroke: A Systematic Review and Meta-Analysis.

The current guideline recommends using an intravenous tissue-type plasminogen activator (IV tPA) prior to mechanical thrombectomy (MT) in eligible acute ischemic stroke (AIS) with emergent large vessel occlusion (ELVO). Some recent studies found no significant differences in the long-term functional outcomes between bridging therapy (BT, i.e., IV tPA prior to MT) and direct MT (dMT). We conducted a systematic review and meta-analysis to compare the safety and functional outcomes between BT and dMT in AIS patients with ELVO who were eligible for IV tPA administration. Based on the ELVO location, patients were categorized as the anterior group (occlusion of the anterior circulation), or the combined group (occlusion of the anterior and/or posterior circulation). A subgroup analysis was performed based on the study type, i.e., RCT and non-RCT. Thirteen studies (3985 patients) matched the eligibility criteria. Comparing the BT and dMT groups, no significant differences in terms of mortality and good functional outcome were observed at 90 days. Symptomatic intracranial hemorrhagic (sICH) events were more frequent in BT patients in the combined group (OR = 0.73, p = 0.02); this result remained significant only in the non-RCT subgroup (OR = 0.67, p = 0.03). The RCT subgroup had a significantly higher rate of successful revascularization in BT patients (OR = 0.73, p = 0.02). Our meta-analysis uncovered no significant differences in functional outcome and mortality rate at 90 days between dMT and BT in patients with AIS who had ELVO. Although BT performed better in terms of successful recanalization rate, there is a risk of increased sICH rate in this group.

Tissue-type plasminogen activator induces conditioned receptive field plasticity in the mouse auditory cortex

Tissue-type plasminogen activator (tPA) is a serine protease that is expressed in various compartments in the brain. It is involved in neuronal plasticity, learning and memory, and addiction. We evaluated whether tPA, exogenously applied, could influence neuroplasticity within the mouse auditory cortex. We used a frequency-pairing paradigm to determine whether neuronal best frequencies shift following the pairing protocol. tPA administration significantly affected the best frequency after pairing, whereby this depended on the pairing frequency relative to the best frequency. When the pairing frequency was above the best frequency, tPA caused a best frequency shift away from the conditioned frequency. tPA significantly widened auditory tuning curves. Our data indicate that regional changes in proteolytic activity within the auditory cortex modulate the fine-tuning of auditory neurons, supporting the function of tPA as a modulator of neuronal plasticity.

Liquid Chromatography Fingerprint Analysis of Released Compounds in Plasma Samples of Stroke Patients after Thrombolytic Treatment

Plasma samples obtained from stroke patients treated with recombinant tissue-type plasminogen activator (rt-PA) and not treated with rt-PA were evaluated with different HPLC methodologies to obtain information about the possible release of small molecules as a result of the thrombolytic treatment. Plasma samples, without derivatization and derivatized with 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate (AQC), were evaluated with a HPLC gradient method, which consisted of a mobile phase of 10 mM ammonium acetate buffered solution (pH = 5.3) and acetonitrile. Three different detection methods were applied: UV, fluorescence, and ESI-MS. The results obtained showed that a group of new highly hydrophilic compounds appeared in most samples analyzed from treated patients, just after the administration of rt-PA. These compounds appeared shortly after the administration of the drug and were detected during the first 24 h after treatment, disappearing from plasma after this time. These new compounds were not detected either in controls or in non-treated stroke patients, which suggests that they were released into the plasma as a consequence of the thrombolytic effect of the drug. Our results suggest that these new compounds might be free glycans. The use of AQC as a derivatizing reagent has demonstrated that the new compounds detected cannot contain primary or secondary amine groups in their structure. The molecular mass determined by ESI-MS (821 Da) suggests that if these compounds are free glycans they might be a high-mannose type.

ФУНКЦИОНАЛЬНАЯ АКТИВНОСТЬ ЭНДОТЕЛИЯ В СИСТЕМНОМ И МЕСТНОМ КРОВОТОКЕ У ПАЦИЕНТОВ ОБЛИТЕРИРУЮЩИМ АТЕРОСКЛЕРОЗОМ И РАЗВИТИЕ РЕСТЕНОЗА ПОСЛЕ ОПЕРАЦИИ БЕДРЕННО-ПОДКОЛЕННОГО ШУНТИРОВАНИЯ

Objective: To analyze the role of markers of the endothelial dysfunction in the vessels of the systemic and local blood flow before and after femoropopliteal bypass surgery (FPBS) in the development of restenosis at obliterating lesions of the femoropopliteal arterial segment (FPAS). Methods: The results of the examination and treatment of 82 patients with obliterating atherosclerosis who underwent FPBS were analyzed. Before and after surgery they underwent testing for serum homocysteine, oxidized low-density lipoprotein, soluble vascular cell adhesion molecule-1 (sVCAM-1), plasminogen activator inhibitor-1 (PAI-1), tissue-type plasminogen activator (t-PA), and annexin V in the systemic and local blood flow. Based on the condition of the reconstruction zone after 12 months, all patients were divided into two groups. Group 1 included patients without restenosis (n=21), and Group 2 – with restenosis (n=61). Results: Before surgery Group 2 patients showed significant differences in the severity of adhesive and hemostatic forms of endothelial dysfunction, as well as apoptosis in comparison with Group 1. It was found that before surgery, Group 2 patients had a significantly higher level of sVCAM-1 in the local bloodstream (by 37.5%, p=0.014), PAI-1 in the systemic and local bloodstream (by 15.6%, p=0.010, and by 16.4%, p=0.008 respectively) and annexin V in the systemic and local bloodstream (by 48.9%, p=0.012 and by 60.2%, p=0.002 respectively). After surgery Group 2 patients had significantly higher levels of PAI-1 in the systemic (by 18.9%, p=0.004) and local (by 11.1%, p=0.049) blood flow, and annexin V in the systemic circulation (by 28.4%, p=0.011) compared with Group 1. Thus increased levels of sVCAM-1 in the local bloodstream, PAI-1, and annexin V – in the systemic and local bloodstream before surgery were associated with postoperative development of restenosis, while higher values of PAI-1 in the systemic and local bloodstream and annexin V in the systemic circulation after surgery were related to subsequent restenosis development. Conclusion: The results of the study indicate impairment of the adhesive and hemostatic function of the endothelium, and increased level of apoptosis in the blood vessels of systemic and local blood flow in patients with restenosis, which can be used to develop personalized approach to management of this disorder and improve the results of revascularization interventions on FPAS. Keywords: Obliterating atherosclerosis of the lower extremities, femoropopliteal bypass surgery, functional activity of the endothelium, restenosis.

A modified mouse model of haemorrhagic transformation associated with tPA administration after thromboembolic stroke

ObjectiveTo establish a new mouse model of haemorrhagic transformation associated with delayed tissue-type plasminogen activator (tPA) treatment to provide a novel tool to study therapeutic strategies for haemorrhagic transformation. MethodsMale C57BL/6 mice were subjected to carotid artery thrombosis stimulated with ferric chloride. The thrombus was then mechanically detached to induce migration toward the intracranial circulation. To induce haemorrhagic transformation, mice were intravenously injected with 10 mg/kg tPA 4.5 h after the onset of ischaemia and were sacrificed 24 h after tPA treatment. ResultsIn this new model, administration of tPA 4.5 h after stroke exacerbated the risk of intracerebral haemorrhage. Thrombolysis with tPA also exacerbated cerebral infarction, brain oedema, blood–brain barrier breakdown, and neurological deficits. However, cerebral blood flow was not significantly affected. ConclusionThe present model is reproducible, easy to perform, and mimics the clinical situation of haemorrhagic transformation after tPA treatment in humans. This modified model can be used as a new tool to test experimental drugs for haemorrhagic transformation associated with delayed tPA administration after an ischaemic stroke.

A New Index for the Prediction of In-Hospital Mortality in Patients with Acute Pulmonary Embolism: The Modified Shock Index.

Pulmonary embolism severity index, its simplified version, and shock index have been used for risk stratification in acute pulmonary embolism. In this study, we proposed a modification in severity index and evaluated the correlates and prognostic value of modification in severity index in this setting. The study group comprised retrospectively evaluated 181 patients with acute pulmonary embolism. Systematic workup including pulmonary embolism severity index, its simplified version, shock index, biomarkers, and echocardiographic and multidetector computed tomography assessments was performed in all patients. Moreover, we calculated modification in severity index by multiplying original shock index (heart rate/systolic blood pressure ratio) and a third component, 1/pulse oxymetric saturation (pSat O2%) ratio. The primary endpoint was defined as all-cause mortality and hemodynamic collapse during the hospital stay. On the basis of initial risk stratification, ultrasound-assisted thrombolysis, systemic tissue-type plasminogen activator, and unfractionated heparin therapies were utilized in 83 (45.9%), 37 (20.4%), and 61 (33.7%) patients, respectively. The primary end-point occurred in 13 (7.2%) patients. Receiver-operating curve analysis revealed that modification in severity index had the highest area under the curve of 0.739 (0.588-0.890, P =.002) compared with shock index, pulmonary embolism severity index, or its simplified version. The modification in severity index > 0.989 predicted primary endpoint with 73% sensitivity and 54% specificity. The modification in severity index seems to be a simple, quick, and compre-hensive risk assessment tool for bedside evaluation at initial stratification, in monitoring the clinical benefit from therapies, and decision-making for escalation to other reperfusion strategies in patients with acute pulmonary embolism. However, the prognostic value of modification in severity index needs to be validated with further studies.

NDRG1 Signaling Is Essential for Endothelial Inflammation and Vascular Remodeling.

NDRG-1 (N-myc downstream-regulated gene 1) is a member of NDRG family that plays essential roles in cell differentiation, proliferation, and stress responses. Although the expression of NDRG1 is regulated by fluid shear stress, its roles in vascular biology remain poorly understood. The purpose of the study is to determine the functional significance of NDRG1 in vascular inflammation and remodeling. By using quantitative polymerase chain reaction, western blot, and immunohistochemistry, we demonstrate that the expression of NDRG1 is markedly increased in cytokine-stimulated endothelial cells and in human and mouse atherosclerotic lesions. To determine the role of NDRG1 in endothelial activation, we performed loss-of-function studies using NDRG1 short hairpin RNA. Our results demonstrate that NDRG1 knockdown by lentivirus bearing NDRG1 short hairpin RNA substantially attenuates both IL-1β (interleukin-1β) and TNF-α (tumor necrosis factor-α)-induced expression of cytokines/chemokines and adhesion molecules. Intriguingly, inhibition of NDRG1 also significantly attenuates the expression of procoagulant molecules, such as PAI-1 (plasminogen activator inhibitor type 1) and TF (tissue factor), and increases the expression of TM (thrombomodulin) and t-PA (tissue-type plasminogen activator), thus exerting potent antithrombotic effects in endothelial cells. Mechanistically, we showed that NDRG1 interacts with orphan Nur77 (nuclear receptor) and functionally inhibits the transcriptional activity of Nur77 and NF-κB (nuclear factor Kappa B) in endothelial cells. Moreover, in NDRG1 knockdown cells, both cytokine-induced mitogen-activated protein kinase activation, c-Jun phosphorylation, and AP-1 (activator protein 1) transcriptional activity are substantially inhibited. Neointima and atherosclerosis formation induced by carotid artery ligation and arterial thrombosis were markedly attenuated in endothelial cell-specific NDRG1 knockout mice compared with their wild-type littermates. Our results for the first time identify NDRG1 as a critical mediator implicated in regulating endothelial inflammation, thrombotic responses, and vascular remodeling, and suggest that inhibition of NDRG1 may represent a novel therapeutic strategy for inflammatory vascular diseases, such as atherothrombosis and restenosis.

Pneumococcal proteins ClpC and UvrC as novel host plasminogen binding factors.

Two plasminogen binding proteins were identified from a mouse infected with Streptococcus pneumoniae. The pneumococcal proteins were annotated as ATP-dependent Clp protease ATP-binding subunit (ClpC) and excinuclease ABC subunit C (UvrC) using the isobaric tags for relative and absolute quantification (iTRAQ) method. Recombinants of both proteins showed significant binding to plasminogen and were found to promote plasminogen activation by tissue-type plasminogen activator. In addition, ClpC and UvrC were LytA-dependently released into the culture supernatant and bound to the bacterial surface. These results suggest that S. pneumoniae releases ClpC and UvrC by autolysis and recruits them to the bacterial surface, where they bind to plasminogen and promote its activation, contributing to extracellular matrix degradation and tissue invasion.

Impact of Decompressive Craniectomy on Hemorrhagic Transformation in Malignant Ischemic Stroke in Mice.

Endovascular thrombectomy has changed the management of ischemic stroke. The reperfusion can however lead to a hemorrhagic transformation (HT). Decompressive craniectomy (DC) is a surgical procedure used for malignant ischemic stroke. However, its efficacy was demonstrated before the era of endovascular thrombectomy trials. Here, we hypothesized that DC for ischemic stroke after thrombectomy could lead to a higher risk of HT. We thus evaluated this hypothesis in a mouse model of stroke induced by occlusion of the middle cerebral artery (MCAO) with or without mechanical reperfusion. Ninety mice subjected to MCAO were divided into 6 groups: permanent MCAO with or without DC; MCAO followed by a mechanical reperfusion with or without DC and MCAO with a mechanical reperfusion followed by r-tPA (recombinant tissue-type plasminogen activator)-induced reperfusion with or without DC. Mice were evaluated by magnetic resonance imaging 24 hours after the MCAO to assess ischemic lesion volumes, and the rate, type, and volume of HTs. The ischemic volume was higher in the 2 groups without reperfusion than in the 4 groups with reperfusion independently of r-tPA treatment and DC. The distribution of HT types was different between the 6 groups. The HT volumes and HT scores was smaller in the 2 groups without reperfusion and in the reperfusion group without r-tPA and without DC. In mice having reperfusion, the mean HT score was higher in mice who had DC without r-tPA (HT score 5; P=0.048) or with r-tPA (HT score 8; P=0.02), than in mice without DC (HT score 1). DC for a malignant stroke, after reperfusion, corresponding to an endovascular thrombectomy failure, increases the risk of severe hemorrhagic transformations in a model of ischemic stroke in mice. This result support the need of clinical studies to evaluate the added value of DC at the era of endovascular thrombectomy.