Conformation-Specific Blockade of the Integrin GPIIb/IIIa

Imaging of Thromboinflammation by Multispectral 19F MRI

The close interplay between thrombotic and immunologic processes plays an important physiological role in the immune defence after tissue injury and has the aim to reduce damage and to prevent the spread of invading pathogens. However, the uncontrolled or exaggerated activation of these processes can lead to pathological thromboinflammation. Thromboinflammation has been shown to worsen the outcome of cardiovascular, autoinflammatory, or even infectious diseases. Imaging of thromboinflammation is difficult because many clinically relevant imaging techniques can only visualize either inflammatory or thrombotic processes. One interesting option for the noninvasive imaging of thromboinflammation is multispectral 19F magnetic resonance imaging (MRI). Due to the large chemical shift range of the 19F atoms, it is possible to simultaneously visualize immune cells as well as thrombus components with specific 19F tracer that have individual spectral 19F signatures. Of note, the 19F signal can be easily quantified and a merging of the 19F datasets with the anatomical 1H MRI images enables precise anatomical localization. In this review, we briefly summarize the background of 19F MRI for inflammation imaging, active targeting approaches to visualize thrombi and specific immune cells, introduce studies about multispectral 19F MRI, and summarize one study that imaged thromboinflammation by multispectral 19F MRI.

Ginsenoside CK targets PHD2 to prevent platelet adhesion and enhance blood circulation by modifying the three-dimensional arrangement of collagen

Platelets are indispensable for physiological hemostasis and pathological thrombus formation, and platelet adhesion to endothelial collagen is a critical initial step in thrombus formation, often overlooked in current antiplatelet therapies. This study aims to elucidate how ginsenoside CK enhances hemodynamic circulation, alleviates stasis, and proposes therapeutic mechanisms. Inspired by the effects on improving microcirculatory disturbances in an acute soft tissue injury model, CK was identified as a PHD2 inhibitor, effectively suppressing platelet adhesion to collagen. It was proposed that targeting PHD2 regulates collagen hydroxylation modification, thereby influencing the formation of its three-dimensional structure, reducing the binding affinity between VWF and collagen, and ultimately suppressing thrombotic events. The efficacy of this mechanism was subsequently confirmed through a mouse DIC model, demonstrating the feasibility of CK in alleviating circulatory disorders. It is worth noting that when Phd2 was knocked down in mice's lungs, pulmonary embolism was significantly reduced. Additionally, PHD2 inhibitors approved for other diseases have exhibited similar anti-thrombotic effects. Moreover, when PHD2 inhibitors were combined with aspirin, they more effectively inhibited arterial thrombosis in rats. The findings offer valuable insights into potential targets for developing antiplatelet drugs or expanding therapeutic applications for existing PHD2 inhibitors in treating thrombotic diseases.

Efficacy and safety of tirofiban in acute ischemic stroke patients with ideal reperfusion: A cohort study of LAA and CE subgroups

BACKGROUND AND OBJECTIVES

Despite achieving ideal reperfusion (eTICI = 3) through endovascular treatment (EVT), some acute ischemic stroke (AIS) patients still experience poor outcomes. This study aims to evaluate the efficacy and safety of tirofiban in AIS patients with ideal reperfusion, focusing on its effects in large artery atherosclerosis (LAA) and cardioembolic (CE) stroke.

METHODS

A total of 474 AIS patients from the RESCUE-BT database were included. Patients were assigned to either the tirofiban or placebo group based on the treatment received. The primary outcome was favorable functional recovery at 90 days (mRS ≤2), and safety outcomes included symptomatic intracranial hemorrhage (sICH) and 90-day mortality. Multivariable logistic regression was used to adjust for confounders, and subgroup and interaction analyses assessed tirofiban's efficacy in LAA and CE populations.

RESULTS

In the overall population that achieved ideal reperfusion, Tirofiban did not improve clinical outcomes and did not increase the risk of mortality or incidence of sICH (p > 0.05). However, subgroup analysis indicated potential clinical benefits for patients with higher NIHSS scores in the LAA group, especially in the subgroup with NIHSS scores >13 (adjusted OR 4.671, 95% CI [1.545, 14.122]). No significant differences were found in the CE group.

CONCLUSIONS

Tirofiban showed potential benefits for LAA patients with ideal reperfusion, especially those with NIHSS scores above 13. Careful patient selection is recommended.

Efficacy and safety of tirofiban in acute ischemic stroke due to intracranial atherosclerotic disease for patients undergoing endovascular treatment: a systematic review and meta-analysis

PURPOSE

Tirofiban has emerged as an adjunct therapy for acute ischemic stroke (AIS) patients undergoing endovascular treatment (EVT). However, its benefits for AIS patients with intracranial atherosclerotic disease (ICAD) remains unclear. This meta-analysis evaluates its efficacy and safety in ICAD-related AIS patients undergoing EVT.

METHODS

We searched PubMed, Cochrane, and Embase up to September, 2024, for studies comparing tirofiban to placebo or no intervention in ICAD-related AIS. Primary outcome was modified Rankin Scale (mRS) 0-2 at 90 days. Secondary outcomes included 90-day mRS 0-1, mRS score at 90 days, successful reperfusion, 90-day mortality, postprocedural reocclusion, and symptomatic/non-symptomatic intracranial hemorrhage (ICH). Subgroup analyses evaluated tirofiban administration routes (intravenous, intra-arterial, or combined).

RESULTS

Thirteen studies comprising 3,572 patients were included. Intravenous tirofiban significantly increased mRS 0-2 (RR 1.26 [95% CI 1.13; 1.42]; p < 0.0001, I²= 0%), mRS 0-1(RR 1.24 [95% CI 1.05; 1.45]; p = 0.0098, I² = 0%), reduced mRS score by 0.58 points ([95% CI -0.99; -0.17]; p = 0.006, I²= 66%) and decreased mortality (RR 0.68 [95% CI 0.57; 0.80]; p < 0.0001, I²= 8%) at 90 days compared to control. Tirofiban overall reduced postprocedural reocclusion relative to control (RR 0.36 [95% CI 0.14; 0.94]; p = 0.036, I²= 73%). No significant differences were observed in successful reperfusion or ICH.

CONCLUSION

Intravenous tirofiban demonstrated an efficacy and safety profile, improving functional recovery and reducing mortality. Tirofiban overall reduced postprocedural reocclusion compared to control. No significant differences were found between groups in successful reperfusion or ICH. These findings support tirofiban as a safe and effective EVT adjunct.

SYSTEMATIC REVIEW PROTOCOL

PROSPERO (CRD42024606522).

Clinical efficacy of tirofiban in the endovascular therapy of patients with acute ischaemic stroke due to intracranial atherosclerotic disease: A meta-analysis

OBJECT

The treatment results of combination of arterial injection of tirofiban with endovascular therapy (EVT) for acute large vessel occlusion (LVO) stroke due to intracranial atherosclerotic disease (ICAD) were inconsistent. This meta-analysis aims to assess the safety and efficacy of ICAD-LVO treatment by intra-arterial injection of tirofiban combined with EVT.

METHODS

Relevant studies were identified through a systematic literature search in Pubmed, EMBASE, Web of Science and Cochrane Library databases, covering articles published from January 2010 to July 2024. The efficacy outcomes assessed in the meta-analysis included favorable functional outcome and recanalization rates. Safety outcomes included mortality and symptomatic intracranial haemorrhage (sICH).

RESULTS

The meta-analysis consisted of data from 11 studies, which included 1 randomised controlled trial (RCT), 5 prospective cohort studies, and 5 retrospective cohort studies, encompassing a total of 2869 patients. The findings showed that tirofiban+EVT for ICAD-LVO was associated with significant improvements in favorable functional outcomes (RR, 1.12; 95 %CI, 1.04-1.21; P=0.005) and reductions in mortality rates (RR, 0.72; 95 %CI, 0.62-0.83; P<0.0001), despite no significant differences in the incidence of sICH (RR, 0.75; 95 % CI, 0.55-1.02; P=0.07) and recanalization rates (RR, 1.02; 95 % CI, 0.99-1.05; P=0.15). Subgroup analysis showed that the application of tirofiban significantly increased favorable functional outcomes in patients with anterior circulation stroke (RR, 1.23; 95 % CI, 1.06-1.42; P=0.005), but there was no significant difference in posterior circulation stroke (RR, 1.08; 95 % CI, 0.83-1.41; P=0.55). In addition, the use of tirofiban in patients with posterior circulation stroke might reduce the incidence of sICH (RR, 0.50; 95 % CI, 0.26-0.96; P=0.04).

CONCLUSION

Tirofiban combined with EVT may be an effective treatment strategy for the treatment of ICAD-LVO, but only for patients with anterior circulation and remains unclear for patients with posterior circulation.

Prevention of early thrombosis in transplanted vein model by encapsulation with tirofiban microneedle drug delivery system

Early thrombosis following coronary artery bypass grafting (CABG) surgery leads to perioperative myocardial infarction, which causes difficulties for clinicians and patients. Moreover, once perioperative myocardial infarction occurs, the mortality rate is extremely high. In recent years, microneedle (MN) drug delivery systems have become a research hotspot with broad clinical application prospects. These systems are capable of achieving sustained, safe, and painless local drug release. In cardiovascular applications, MNs maximize local anticoagulant effects, inhibit endometrial hyperplasia, and reduce systemic side effects. We speculate that a MN drug delivery system can be used to target transplanted veins to inhibit their thrombosis and reduce the incidence of perioperative myocardial infarction after CABG surgery. Therefore, this study developed a hyaluronic acid MN patch loaded with tirofiban and conducted preliminary physicochemical tests. The safety, efficacy, biocompatibility, and targeting of the MN system were evaluated usingin vitroandin vivoexperiments using a jugular vein transplantation model. The results indicate that the MN system has excellent physical properties, safety, effectiveness, biocompatibility, and strong targeting, which can effectively inhibit early local thrombus formation. In addition, the observation of early postoperative endometrial hyperplasia activation provides a foundation for future research.

Novel GPIb-independent platelet aggregation induced by botrocetin: implications for diagnosis and antithrombotic therapy

BACKGROUND

Snake venom botrocetin facilitates von Willebrand factor (VWF) binding to platelet GPIbα and has been widely used for the diagnosis of von Willebrand disease and GPIb-related disorders. Botrocetin is also commonly employed for the development/characterization of antithrombotics targeting the GPIb-VWF axis.

OBJECTIVES

To explore the alternative receptor(s)/mechanisms that participate in botrocetin-induced platelet aggregation.

METHODS

The effects of botrocetin on platelet aggregation were examined using platelets from wild-type, VWF- and fibrinogen-deficient, GPIbα-deficient, IL4Rα/GPIbα-transgenic, ITGA2B and ITGB3-deficient mice, and Bernard-Soulier syndrome and healthy human samples. Platelet-fibrinogen and platelet-VWF interaction were measured using flow cytometry. GPIbα-VWF binding was evaluated utilizing enzyme-linked immunosorbent assay. Botrocetin-αIIbβ3 and botrocetin-GPIbα interactions were measured using enzyme-linked immunosorbent assay and fluorescence anisotropy assays. Heparinized whole blood from healthy donors was examined for thrombus formation and growth in a perfusion chamber.

RESULTS

Botrocetin could induce aggregation of platelets from a Bernard-Soulier syndrome patient and GPIbα-deficient mice as well as platelets lacking the N-terminal extracellular domain of GPIbα. Botrocetin could interact with αIIbβ3 and facilitated αIIbβ3-VWF interaction independent of GPIb. Botrocetin competitively bound to the ligand-binding domain of activated rather than resting αIIbβ3. Although botrocetin-induced platelet aggregation requires VWF, strikingly, in the absence of VWF, botrocetin blocked fibrinogen and other ligand binding to αIIbβ3 and inhibited platelet aggregation and thrombus formation. Consistently, recombinant botrocetin defective in VWF binding inhibited αIIbβ3- and GPIb-mediated platelet aggregation, spreading, and thrombus formation.

CONCLUSION

Our study provides insights into avoiding the misdiagnosis of GPIb-related disorders and developing botrocetin mutants as potential new antithrombotics that may simultaneously target both αIIbβ3 and GPIbα.

Platelet integrin αIIbβ3 plays a key role in a venous thrombogenesis mouse model

Venous thrombosis (VT) is a common vascular disease associated with reduced survival and a high recurrence rate. VT is initiated by the accumulation of platelets and neutrophils at sites of endothelial cell activation. A role for platelet αIIbβ3 in VT is not established, a task complicated by the increased bleeding risk caused by partial agonists such as tirofiban. Here, we show that m-tirofiban, a modified version of tirofiban, does not agonize αIIbβ3 based on lack of neoepitope expression and the cryo-EM structure of m-tirofiban/full-length αIIbβ3 complex. m-tirofiban abolishes agonist-induced platelet aggregation while preserving clot retraction ex vivo and, unlike tirofiban, it suppresses venous thrombogenesis in a mouse model without increasing bleeding. These findings establish a key role for αIIbβ3 in VT initiation and suggest that m-tirofiban and compounds with a similar structurally-defined mechanism of action merit consideration as potential thromboprophylaxis agents in patients at high risk for VT and hemorrhage.

Safety and efficacy of adjunct tirofiban treatment following mechanical thrombectomy for acute ischemic stroke patients with large vessel occlusion (LVO) resulting in successful reperfusion

BACKGROUND AND PURPOSE

Tirofiban administration after mechanical thrombectomy (MT) remains controversial. This study aimed to investigate the efficacy and safety of adjunct tirofiban treatment following MT for acute ischemic stroke (AIS) patients with large vessel occlusion (LVO) that resulted in successful reperfusion on digital subtraction angiography (DSA).

METHODS

This retrospective study was conducted in Zhengzhou University University People's Hospital, an advanced stroke center in China. Consecutive patients with AIS who underwent endovascular therapy (EVT) were enrolled from June 2018 to January 2022. The safety endpoints were symptomatic intracerebral hemorrhage (sICH), total intracranial hemorrhage (ICH), and 3-month mortality. The efficacy endpoints were 3-month modified Rankin scale (mRS) score and 24-h neurological improvement.

RESULTS

A total of 145 consecutive patients with AIS who underwent MT were analyzed, of whom 51 (35.2%) patients were in the tirofiban group. There were 30 (20.7%) patients with sICH, 50 (34.5%) patients suffered from ICH within 24-h post-MT, and 47 (32.4%) dead at 3-month. Besides, 31 (21.4%) patients achieved excellent clinical outcomes (mRS, 0-1), and 24-h neurological improvement was found in 29 (20.0%) patients. No statistically significant differences were found in safety outcomes on sICH, total ICH, and 3-month mortality, as well as efficacy outcomes on 3-month mRS scores (0-1) and 24-h neurological improvement between the two groups (P > 0.05 for all). Additionally, tirofiban was associated with 3-month mRS scores of 0-2 (adjusted odds ratio (OR), 3.75; 95% confidence interval (CI), 1.41-10.02, P = 0.008).

CONCLUSION

Adjunct tirofiban treatment following MT for AIS patients with LVO that resulted in successful reperfusion on DSA was not correlated with the increased risk of safety endpoints on sICH, ICH, and 3-month mortality, and it may be associated with a lower 3-month mRS score.

How Protein Depletion Balances Thrombosis and Bleeding Risk in the Context of Platelet's Activatory and Negative Signaling

Platelets are small cell fragments that play a crucial role in hemostasis, requiring fast response times and fine signaling pathway regulation. For this regulation, platelets require a balance between two pathway types: the activatory and negative signaling pathways. Activatory signaling mediators are positive responses that enhance stimuli initiated by a receptor in the platelet membrane. Negative signaling regulates and controls the responses downstream of the same receptors to roll back or even avoid spontaneous thrombotic events. Several blood-related pathologies can be observed when these processes are unregulated, such as massive bleeding in activatory signaling inhibition or thrombotic events for negative signaling inhibition. The study of each protein and metabolite in isolation does not help to understand the role of the protein or how it can be contrasted; however, understanding the balance between active and negative signaling could help develop effective therapies to prevent thrombotic events and bleeding disorders.

Administration of a new nano delivery system coated with Tirofiban to prevent early thrombosis of vein graft

OBJECTIVE

To verify the administration of a new nano delivery system coated with Tirofiban on preventing early thrombosis in vein graft.

METHODS

Forty New Zealand white rabbits were randomly divided into five groups with eight rabbits in each group. The rabbits of all groups underwent jugular vein transplantation, except group I with only neck opening and closing operation. Vein grafts of group II were preprocessed by intravenous injection of normal saline; group III were preprocessed by tirofiban alone; group IV were preprocessed by unloaded nanoparticles of PLGA-PEG; group V were preprocessed by PLGA-PEG coated with tirofiban. Coagulation and platelet function of peripheral and vein graft blood were detected at 1, 2, 4, 12 h and 1, 3, 7, 10, 14 days after operation. Patency rate of vein graft and blood flow index were measured by vascular ultrasound at third, seventh, 10th, and 14th days after operation; two rabbits in each group were randomly sacrificed at the corresponding time of detection. Pathological differences of vein grafts were observed by HE stainin.

RESULTS

The patency rate of vein grafts in group V was significantly higher than that in group II to IV. The platelet and platelet aggregation rate in group V were inhibited in vein graft blood significantly. The post-operative PT and APTT in vein graft blood in group V were increased obviously while the FBG, D-dimer and FDP were significantly inhibited. Except group I, the lumen loss rate of vein grafts in group V was significantly lower than that in other groups, and vein graft blood in group V had a significant lower expression of platelet P-selectin and GP IIb/IIIa receptor than that in other groups.

CONCLUSION

This study proves that PEG-PLGA coated with tirofiban can effectively prevent early vein graft stenosis from thrombosis by inhibition of platelet function, coagulation function.

Fibrinogen binding to activated platelets and its biomimetic thrombus-targeted thrombolytic strategies

Thrombosis is associated with various fatal arteriovenous syndromes including ischemic stroke, myocardial infarction, and pulmonary embolism. However, current clinical thrombolytic treatment strategies still have many problems in targeting and safety to meet the thrombolytic therapy needs. Understanding the molecular mechanism that underlies thrombosis is critical in developing effective thrombolytic strategies. It is well known that platelets play a central role in thrombosis and the binding of fibrinogen to activated platelets is a common pathway in the process of clot formation. Based on this, a concept of biomimetic thrombus-targeted thrombolytic strategy inspired from fibrinogen binding to activated platelets in thrombosis was proposed, which could selectively bind to activated platelets at a thrombus site, thus enabling targeted delivery and local release of thrombolytic agents for effective thrombolysis. In this review, we first summarized the main characteristics of platelets and fibrinogen, and then introduced the classical molecular mechanisms of thrombosis, including platelet adhesion, platelet activation and platelet aggregation through the interactions of activated platelets with fibrinogen. In addition, we highlighted the recent advances in biomimetic thrombus-targeted thrombolytic strategies which inspired from fibrinogen binding to activated platelets in thrombosis. The possible future directions and perspectives in this emerging area are briefly discussed.

Safety and efficacy of tirofiban treatment in the endovascular treatment of patients with acute ischaemic stroke - A meta-analysis

OBJECT

The use of endovascular therapy (EVT) has become a widespread strategy for the clinical management of acute ischemic stroke (AIS). However, the combination of arterial injection of tirofiban with EVT for AIS continues to be a subject of controversy. This meta-analysis was conducted to assess the safety and efficacy of this treatment approach.

METHODS

Relevant studies were identified through a systematic literature search in Pubmed, EMBASE, Web of Science, and Cochrane Library databases, covering articles published from January 2010 to January 2023. The efficacy outcomes included favorable functional outcomes, recanalization rates, and safety outcomes including mortality and symptomatic intracranial hemorrhage (sICH).

RESULTS

The meta-analysis consisted of data from 13 studies, which included 1 randomized controlled trial (RCT), 7 prospective cohort studies, and 5 retrospective cohort studies, encompassing a total of 3477 patients. The study results indicate that the intra-arterial (IA) tirofiban+EVT for AIS is associated with significant improvements in favorable functional outcomes (OR, 1.21; 95%CI, 1.05-1.40; P = 0.009) and recanalization rate (OR, 1.33; 95%CI, 1.06-1.65; P = 0.01), as well as significant reductions in mortality rates (OR, 0.65; 95%CI, 0.53-0.79; P = 0.0001). Subgroup analysis revealed that administering a maintenance dose of intravenous (IV) tirofiban post-EVT was significantly associated with improved functional outcomes and reduced mortality in patients. In addition, there was no increase in the incidence of sICH (OR, 0.92; 95%CI, 0.71-1.20; P = 0.54).

CONCLUSION

The administration of Intra-arterial tirofiban combined with EVT is an effective and safe treatment strategy for AIS, and postoperative maintenance doses of intravenous tirofiban may be more effective than IA only.

Analysis of rescue strategies for acute thrombosis during STA-MCA bypass surgery and the literature review

BACKGROUND AND OBJECTIVES

STA-MCA bypass surgery is mainly used for Moyamoya disease, giant intracranial aneurysms, and resection of intracranial tumors requiring sacrifice of blood vessels. The intraoperative patency of the reconstructive vessels is critical to the efficacy of the procedure. This study aimed to evaluate the efficacy of intra-arterially infused tirofiban for the treatment of acute thrombosis during STA-MCA bypass surgery and countermeasures for acute thrombosis.

METHODS

This study involved 209 patients (272 hemispheres) who underwent STA-MCA surgery between November 2020 and December 2023. Intraoperative acute thrombosis occurred in eight patients (3.83%,8 hemispheres). We retrospectively reviewed the clinical and imaging data, surgical procedure, and follow-up outcomes of eight patients. We implemented the different thrombolytic methods to evaluate the optimal thrombosis management during the bypass surgery. After three months, we assessed neurological functions using the modified Rankin Scale (mRS) and conducted a literature review using PubMed.

RESULTS

Eight patients (four male patients and four female patients) developed acute thrombosis during the bypass surgery. Of the eight patients, two underwent re-anastomosis after thrombus removal, three received local injections of tirofiban into the anastomosis or the branches of the superficial temporal artery, and three underwent superselective intra-arterial tirofiban infusion using a microcatheter. Thrombosis were resolved, and arteries were recanalized in all patients. The mRS score was 0 in all patients. No major ischemic or hemorrhagic complications occurred.

CONCLUSION

Our treatment methods were efficacious in the management of acute thrombosis. Intra-arterial tirofiban administration seems to be a simple and effective treatment option for acute thrombosis during STA-MCA bypass surgery.

Platelet integrin αIIbβ3 plays a key role in venous thrombogenesis in a mouse model

Venous thrombosis (VT) is a common vascular disease associated with reduced survival and a high recurrence rate. Previous studies have shown that the accumulation of platelets and neutrophils at sites of endothelial cell activation is a primary event in VT, but a role for platelet αIIbβ3 in the initiation of venous thrombosis has not been established. This task has been complicated by the increased bleeding linked to partial agonism of current αIIbβ3 inhibitory drugs such as tirofiban (Aggrastat ® ). Here, we show that m-tirofiban, an engineered version of tirofiban, is not a partial agonist of αIIbβ3. This is based on its cryo-EM structure in complex with human full-length αIIbβ3 and its inability to increase expression of an activation-sensitive epitope on platelet αIIbβ3. m-tirofiban abolished agonist-induced platelet aggregation ex vivo at concentrations that preserved clot retraction and markedly suppressed the accumulation of platelets, neutrophils, and fibrin on thrombin-activated endothelium in real-time using intravital microscopy in a mouse model of venous thrombogenesis. Unlike tirofiban, however, m-tirofiban did not increase bleeding at the thrombosis-inhibitory dose. These findings establish a key role for αIIbβ3 in the initiation of VT, provide a guiding principle for designing potentially safer inhibitors for other integrins, and suggest that pure antagonists of αIIbβ3 like m-tirofiban merit further consideration as potential thromboprophylaxis agents in patients at high-risk for VT and hemorrhage.

Predictors of outcome in large vessel occlusion stroke patients with intravenous tirofiban treatment: a post hoc analysis of the RESCUE BT clinical trial

OBJECTIVE

The aim of this study was to investigate the factors influencing good outcomes in patients receiving only intravenous tirofiban with endovascular thrombectomy for large vessel occlusion stroke.

METHODS

Post hoc exploratory analysis using the RESCUE BT trial identified consecutive patients who received intravenous tirofiban with endovascular thrombectomy for large vessel occlusion stroke in 55 comprehensive stroke centers from October 2018 to January 2022 in China.

RESULTS

A total of 521 patients received intravenous tirofiban, 253 of whom achieved a good 90-day outcome (modified Rankin Scale [mRS] 0-2). Younger age (adjusted odds ratio [aOR]: 0.965, 95% confidence interval [CI]: 0.947-0.982; p < 0.001), lower serum glucose (aOR: 0.865, 95%CI: 0.807-0.928; p < 0.001), lower baseline National Institutes of Health Stroke Scale (NIHSS) score (aOR: 0.907, 95%CI: 0.869-0.947; p < 0.001), fewer total passes (aOR: 0.791, 95%CI: 0.665-0.939; p = 0.008), shorter punctures to recanalization time (aOR: 0.995, 95%CI:0.991-0.999; p = 0.017), and modified Thrombolysis in Cerebral Infarction (mTICI) score 2b to 3 (aOR: 8.330, 95%CI: 2.705-25.653; p < 0.001) were independent predictors of good outcomes after intravenous tirofiban with endovascular thrombectomy for large vessel occlusion stroke.

CONCLUSION

Younger age, lower serum glucose level, lower baseline NIHSS score, fewer total passes, shorter punctures to recanalization time, and mTICI scores of 2b to 3 were independent predictors of good outcomes after intravenous tirofiban with endovascular thrombectomy for large vessel occlusion stroke.

CHINESE CLINICAL TRIAL REGISTRY IDENTIFIER

ChiCTR-IOR-17014167.

Efficacy and safety of tirofiban in patients with acute branch atheromatous disease-related stroke (BRANT): a protocol for a randomised controlled trial

INTRODUCTION

Branch atheromatous disease (BAD)-related stroke is increasingly becoming a clinical entity and prone to early neurological deterioration (END) and poor prognosis. There are no effective regimens to reduce the disability caused by BAD-related stroke in acute phase. Recent studies have indicated the efficacy of tirofiban in acute ischaemic stroke; however, its efficacy has not been validated in patients with BAD-related stroke. Thus, we aim to test whether intravenous tirofiban initiated within 48 hours after the onset would improve the functional outcome in patients with acute BAD-related stroke, in comparison with the standard antiplatelet therapy based on the current guideline.

METHODS AND ANALYSIS

BRANT is a multicentre, randomised, open-label, blinded endpoint, parallel-controlled, phase III trial conducted in 21 hospitals in China. Participants aged 18-75 years with acute BAD-related stroke within 48 hours after the stroke onset are randomised in a 1:1 ratio to the tirofiban or control group. The treatment period is 48 hours in both groups. The primary outcome is the excellent functional outcome (modified Rankin Scale Score: 0-1) at 90 days. The secondary outcomes include END, major bleeding, stroke, death, functional status, serious adverse events and change in bleeding-related markers. Assuming the rates of the primary outcome to be 74% in the tirofiban group and 62% in the control group, a total of 516 participants are needed for 0.8 power (two-sided 0.05 alpha).

ETHICS AND DISSEMINATION

BRANT study has been approved by the Ethics Committee of the Peking Union Medical College Hospital (I-23PJ1242). Written informed consent is required for all the patients before enrolment. The results of the study will be published in a peer-reviewed journal.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov (NCT06037889).

Examining the Efficacy, Safety, and Future Prospects of Tirofiban in Managing Myocardial Infarction among Diabetic Patients

BACKGROUND

Myocardial infarction (MI) is a leading cause of death worldwide, particularly in patients with diabetes mellitus (DM). Tirofiban, a platelet GP IIb/IIIa receptor inhibitor, has shown promise as adjunctive therapy in the emergency management of MI in diabetic patients. However, a comprehensive understanding of its use, efficacy, safety, and limitations in this patient population is necessary to optimize treatment strategies and improve patient outcomes.

METHODOLOGY

This review article utilized a systematic approach to gather relevant research articles, clinical trials, and studies on the use of tirofiban in the therapy of MI in diabetic patients. Databases, such as PubMed and Google Scholar, were extensively searched using specific keywords related to tirofiban, MI, DM, STEMI, and antiplatelet therapy. The collected data were carefully examined, summarized, and analyzed to provide an extensive overview of using tirofiban in the management of MI in diabetic individuals.

RESULTS

The analysis of the gathered literature revealed that tirofiban has demonstrated efficacy in improving clinical outcomes, reducing myocardial ischemia-reperfusion injury, and promoting early recovery of heart function in diabetic patients with MI undergoing percutaneous coronary intervention. The fast on- and off-rate and dose-dependent effect of the drug on platelet aggregation contribute to its effectiveness. However, caution should be exercised due to the potential risk of tirofiban-associated thrombocytopenia. Clinical trials and studies have provided evidence- based dosing guidelines, enabling the safe and effective administration of tirofiban in this patient population.

CONCLUSION

Tirofiban, a platelet GP IIb/IIIa receptor inhibitor, shows promise as adjunctive therapy in the emergency management of MI in diabetic patients. It has demonstrated efficacy in improving clinical outcomes, reducing myocardial ischemia-reperfusion injury, and promoting early recovery of heart function. However, healthcare providers should be cautious regarding the potential risk of tirofiban-associated thrombocytopenia. Further research is needed to optimize dosing guidelines, evaluate long-term safety, and fully understand the benefits and limitations of tirofiban in this patient population. The comprehensive insights provided in this review aim to enhance treatment strategies and improve patient outcomes in the emergency management of MI in diabetic individuals.

Molecular mechanisms of catch bonds and their implications for platelet hemostasis

Adhesive molecular bonds between blood cells are essential for thrombosis and hemostasis as they provide means for platelet adhesion, aggregation, and signaling in flowing blood. According to the nowadays conventional definition, a "catch" bond is a type of non-covalent bio-molecular bridge, whose dissociation lifetime counter-intuitively increases with applied tensile force. Following recent experimental findings, such receptor-ligand protein bonds are vital to the blood cells involved in the prevention of bleeding (hemostatic response) and infection (immunity). In this review, we examine the up-to-date experimental discoveries and theoretical insights about catch bonds between the blood cells, their biomechanical principles at the molecular level, and their role in platelet thrombosis and hemostasis.

The relative importance of platelet integrins in hemostasis, thrombosis and beyond

Integrins are heterodimeric transmembrane receptors composed of α and β chains, with an N-terminal extracellular domain forming a globular head corresponding to the ligand binding site. Integrins regulate various cellular functions including adhesion, migration, proliferation, spreading and apoptosis. On platelets, integrins play a central role in adhesion and aggregation on subendothelial matrix proteins of the vascular wall, thereby ensuring hemostasis. Platelet integrins belong either to the β1 family (α2β1, α5β1 and α6β1) or to the β3 family (αIIbβ3 and αvβ3). On resting platelets, integrins can engage their ligands when the latter are immobilized but not in their soluble form. The effects of various agonists promote an inside-out signal in platelets, increasing the affinity of integrins for their ligands and conveying a modest signal reinforcing platelet activation, called outside-in signaling. This outside-in signal ensures platelet adhesion, shape change, granule secretion and aggregation. In this review, we examine the role of each platelet integrin in hemostatic plug formation, hemostasis and arterial thrombosis and also beyond these classical functions, notably in tumor metastasis and sepsis.

Tirofiban for Stroke without Large or Medium-Sized Vessel Occlusion

BACKGROUND

The effects of the glycoprotein IIb/IIIa receptor inhibitor tirofiban in patients with acute ischemic stroke but who have no evidence of complete occlusion of large or medium-sized vessels have not been extensively studied.

METHODS

In a multicenter trial in China, we enrolled patients with ischemic stroke without occlusion of large or medium-sized vessels and with a National Institutes of Health Stroke Scale score of 5 or more and at least one moderately to severely weak limb. Eligible patients had any of four clinical presentations: ineligible for thrombolysis or thrombectomy and within 24 hours after the patient was last known to be well; progression of stroke symptoms 24 to 96 hours after onset; early neurologic deterioration after thrombolysis; or thrombolysis with no improvement at 4 to 24 hours. Patients were assigned to receive intravenous tirofiban (plus oral placebo) or oral aspirin (100 mg per day, plus intravenous placebo) for 2 days; all patients then received oral aspirin until day 90. The primary efficacy end point was an excellent outcome, defined as a score of 0 or 1 on the modified Rankin scale (range, 0 [no symptoms] to 6 [death]) at 90 days. Secondary end points included functional independence at 90 days and a quality-of-life score. The primary safety end points were death and symptomatic intracranial hemorrhage.

RESULTS

A total of 606 patients were assigned to the tirofiban group and 571 to the aspirin group. Most patients had small infarctions that were presumed to be atherosclerotic. The percentage of patients with a score of 0 or 1 on the modified Rankin scale at 90 days was 29.1% with tirofiban and 22.2% with aspirin (adjusted risk ratio, 1.26; 95% confidence interval, 1.04 to 1.53, P = 0.02). Results for secondary end points were generally not consistent with the results of the primary analysis. Mortality was similar in the two groups. The incidence of symptomatic intracranial hemorrhage was 1.0% in the tirofiban group and 0% in the aspirin group.

CONCLUSIONS

In this trial involving heterogeneous groups of patients with stroke of recent onset or progression of stroke symptoms and nonoccluded large and medium-sized cerebral vessels, intravenous tirofiban was associated with a greater likelihood of an excellent outcome than low-dose aspirin. Incidences of intracranial hemorrhages were low but slightly higher with tirofiban. (Funded by the National Natural Science Foundation of China; RESCUE BT2 Chinese Clinical Trial Registry number, ChiCTR2000029502.).

The Effects of Arginine-Based Supplements on Fatigue Levels following COVID-19 Infection: A Prospective Study in Romania

The purpose of this study was to examine the effects of two arginine-based supplements on the fatigue level of patients following the COVID-19 infection. This is a prospective study of the SARS-CoV-2-infected patients divided into two groups (according to family physicians' prescriptions, Group 1 of patients were treated with Astenor Energy® containing arginine aspartate, B6 vitamin, biotin and magnesium, and Group 2 of patients were treated with Astenor Forte® containing L-arginine and malic acid). The patients visited their family physicians from October 2021 to January 2022, complaining of physical and/or mental fatigue following the COVID-19 infection. We recorded 505 patients (146 patients in Group 1 and 359 patients in Group 2) and analyzed the fatigue level using the Fatigue Assessment Scale (FAS) through its total (FAS-T), mental (FAS-M) and physical (FAS-P) scores, at baseline and after three months of treatment. There was no difference between the two groups in terms of age (p = 0.265), but more men were included in Group 1 than in Group 2 (p = 0.001). The patients from Group 2 were significantly more likely to be treated at home than those included in Group 1 (89.7% vs. 65.1%, p < 0.0001) because of the lower severity of the COVID-19 infection (asymptomatic or mild: 82.5% vs. 48.7%, p < 0.0001). After 3 months of treatment, patients indicated no fatigue in the higher percentage compared to than at the baseline (68.7% vs. 27.7%), and the fatigue level significantly decreased both in Group 1 (median baseline 33.0 vs. follow-up 17.00, p < 0.0001) and Group 2 (median baseline 25.0 vs. follow-up 17.00, p < 0.0001). These findings suggest that supplements with L-arginine may be proposed as a remedy to restore physical and mental performance affected by the fatigue burden in people with COVID-19 or following the COVID-19 infection.

RGD and Scutellarin Conjugate (WK001) Targeting Platelet Glycoprotein IIb/IIIa Receptor Protects from Myocardial Ischemia/Reperfusion Injury: Synthesis, Characterization, and Bioactivity Evaluation

Myocardial ischemia/reperfusion (MI/R) injury is an unresolved clinical challenge. The blockade of binding fibrinogen by glycoprotein IIb/IIIa (GPIIb-IIIa) inhibitors has become a new therapeutic approach against MI/R injury. In this study, we modified the RGD structure to combine with scutellarin and synthesized a novel peptide, scutellarin-HomoArg-Gly-Asp-Trp-NH₂ (WK001). Herein, reported experimental and docking evidence indicates that WK001 provides immediate and potent platelet inhibition, with stronger inhibition of platelet aggregation than eptifibatide and scutellarin. In particular, it is administered intravenously to prevent thrombus formation and attenuate myocardial fibrosis progression in vivo. Therefore, WK001 could be developed as an antiplatelet drug to treat thrombosis-associated diseases, such as stroke and myocardial infarction.

The potential impact of nanomedicine on COVID-19-induced thrombosis

Extensive reports of pulmonary embolisms, ischaemic stroke and myocardial infarctions caused by coronavirus disease 2019 (COVID-19), as well as a significantly increased long-term risk of cardiovascular diseases in COVID-19 survivors, have highlighted severe deficiencies in our understanding of thromboinflammation and the need for new therapeutic options. Due to the complexity of the immunothrombosis pathophysiology, the efficacy of treatment with conventional anti-thrombotic medication is questioned. Thrombolytics do appear efficacious, but are hindered by severe bleeding risks, limiting their use. Nanomedicine can have profound impact in this context, protecting delicate (bio)pharmaceuticals from degradation en route and enabling delivery in a targeted and on demand manner. We provide an overview of the most promising nanocarrier systems and design strategies that may be adapted to develop nanomedicine for COVID-19-induced thromboinflammation, including dual-therapeutic approaches with antiviral and immunosuppressants. Resultant targeted and side-effect-free treatment may aid greatly in the fight against the ongoing COVID-19 pandemic.

Chloroplast-boosted photodynamic therapy for effective drug-resistant bacteria killing and biofilm ablation

Due to the misuse of various antibiotics, the problem of bacterial resistance has become more serious worldwide, and the associated diseases have significantly increased the medical burden of society. Antimicrobial photodynamic therapy (PDT) has received widespread attention because of its safety, efficiency, and facile implementation. Here, we report an oxygen-supply antibacterial agent (Ce6@CS/CP), which could enhance the efficacy of antibacterial PDT via photosynthesis of O₂. Ce6@CS/CP displayed a robust interaction with bacteria, hence facilitating the delivery efficiency of Ce6. In vitro experiments demonstrated that the photodynamic bactericidal potency of Ce6@CS/CP was remarkably greater than that of free Ce6. Furthermore, Ce6@CS/CP also exhibited superior significant antibiofilm activity to free Ce6. As a live oxygen-supply antibacterial agent, Ce6@CS/CP possesses excellent bacteria delivery ability of Ce6 and could enhance the potency of antibacterial PDT by photosynthesis, offering a new strategy for fighting against drug-resistant bacteria.

The efficacy and safety of intravenous tirofiban in the treatment of acute ischemic stroke patients with early neurological deterioration

WHAT IS KNOWN AND OBJECTIVE

Many patients with acute ischemic stroke (AIS) develop early neurological deterioration (END), leading to disabilities or death. Thus, this study aimed to investigate the efficacy and safety of intravenous tirofiban in treating patients with AIS and END who missed the thrombolysis time window.

METHODS

A total of 123 AIS-END patients participated in the study between January 2021 and December 2021. Patients were randomized into the tirofiban group (n = 63) and the control group (n = 60) based on whether a tirofiban injection was administered. The National Institute of Health Stroke Scale (NIHSS) was used to assess neurological function at the 48th hour and on the 7th day after intervention, and the modified Rankin Scale (mRS) was used to assess neurological recovery 90 days after AIS. Adverse reactions during the intervention were recorded for safety analysis.

RESULTS AND DISCUSSION

The 7th day NIHSS and 90th day post-AIS mRS scores of the tirofiban group were significantly lower than those of the control group (p < 0.05), while the 90th day good prognosis (mRS ≤ 2) rate of the tirofiban group was significantly higher (84.13% vs. 65.00%, p < 0.05). Logistic regression demonstrated a protective effect of tirofiban for good prognosis in AIS patients with END (OR = 4.675, 95% CI [1.012-21.605], p < 0.05). No cases of intracranial haemorrhage transformation or death were observed during the treatment in either group.

WHAT IS NEW AND CONCLUSION

Tirofiban injection exhibited a high safety profile and significantly improved the prognosis of AIS-END patients who missed the intravenous thrombolysis time window.

Treatment of progressive ischemic stroke with low‑dose eptifibatide: A retrospective case‑control study

Progressive ischemic stroke (PIS) is a therapeutic challenge in clinical practice. The present retrospective study aimed to investigate the safety and effectiveness of eptifibatide in the treatment of PIS. The present study enrolled patients with PIS admitted to Xiangtan Central Hospital (Xiangtan, China) between March 2020 and March 2021 with National Institutes of Health Stroke Scale (NIHSS) progression scores of ≥2 points during the initial 72 h. Patients were then divided into two groups according to their different anti-platelet treatment regimens. The control group was administered anti-platelet aggregation with aspirin 100 mg/day, or aspirin 100 mg/day in combination with clopidogrel 75 mg/day, whilst eptifibatide was administered in the eptifibatide group in addition to the treatment regimen used in the control group. Changes in NIHSS scores at the time of progression and 7 days after treatment (∆NIHSS) were used to assess early neurological recovery, and there were no significant differences in ∆NIHSS and adverse reactions between the groups (P>0.05). Subgroup analysis was subsequently performed according to the type of blood vessel that was involved [large artery atherosclerosis (LAA) or small artery occlusion (SAO)]. For the SAO subgroup, the ∆NIHSS in the eptifibatide group was significantly superior to that of the control group (P=0.008), while for the LAA subgroup, there were no significant differences in ∆NIHSS between groups (P=0.334). The present retrospective study found that patients with PIS tolerated eptifibatide treatment well. Eptifibatide exerted different effects on patients with acute PIS involving different types of blood vessels compared with oral antiplatelet drugs. In addition, application of eptifibatide may lead to faster and earlier recovery in patients with SAO, but not in those with LAA. Low-dose eptifibatide is a safe and effective treatment option for patients with PIS caused by SAO.

Clinical safety and possible efficacy of tirofiban in combination with intravenous thrombolysis by recombinant tissue plasminogen activator for early treatment of capsular warning syndrome (CWS)

The purpose of this study was to assess the efficacy and safety of the combination of tirofiban with intravenous thrombolysis (IVT) in treating patients with capsular warning syndrome (CWS) who failed to respond to the treatment of intravenous thrombolysis alone. Tirofiban was approved for the treatment of CWS patients with fluctuating symptoms or no substantial improvement after intravenous thrombolysis within 24 h in our hospital from October 2019 to June 2021. Patients were evaluated with the National Institutes of Health Stroke Scale (NIHSS) at admission, at 72 h post-thrombolysis, at 1-week, and at 3-months with the modified Rankin Scales (MRS) score. A total of 12 patients received tirofiban and eight patients received control treatment with a history of CWS in our cohort. Among the patients, 13 patients smoked more than one pack of cigarettes a day, 17 had hypertension, 17 had hypercholesterolemia, 7 had diabetes, 1 had the history of cerebral infarction, 2 had atrial fibrillation, 7 had mild big vascular stenosis, 13 had lesions of the perforating branch by imaging, and 19 had acute capsular infarction. In both the tirofiban and control groups, NIHSS scores were significantly reduced after intravenous thrombolysis or 1-week after onset compared with before intravenous thrombolysis (P < 0.001). Before and after intravenous thrombolysis, there were no differences between the tirofiban group and control group (P = 0.970, P = 0.384, respectively). The tirofiban group, however, showed remarkably lower scores in both 1-week NIHSS and 3-month MRS than the control (P = 0.012, P = 0.003, respectively). Our study revealed that tirofiban did not increase the risk of hemorrhage and had favorable clinical efficacy as a remedial treatment for CWS patients with poor prognosis for intravenous thrombolysis, therefore indicating great potential for broader use.

Novel Antithrombotic Agents in Ischemic Cardiovascular Disease: Progress in the Search for the Optimal Treatment

Ischemic cardiovascular diseases have a high incidence and high mortality worldwide. Therapeutic advances in the last decades have reduced cardiovascular mortality, with antithrombotic therapy being the cornerstone of medical treatment. Yet, currently used antithrombotic agents carry an inherent risk of bleeding associated with adverse cardiovascular outcomes and mortality. Advances in understanding the pathophysiology of thrombus formation have led to the discovery of new targets and the development of new anticoagulants and antiplatelet agents aimed at preventing thrombus stabilization and growth while preserving hemostasis. In the following review, we will comment on the key limitation of the currently used antithrombotic regimes in ischemic heart disease and ischemic stroke and provide an in-depth and state-of-the-art overview of the emerging anticoagulant and antiplatelet agents in the pipeline with the potential to improve clinical outcomes.

Safety and Efficacy of Tirofiban During Intravenous Thrombolysis Bridging to Mechanical Thrombectomy for Acute Ischemic Stroke Patients: A Meta-Analysis

Introduction

The safety and efficacy of tirofiban in intravenous thrombolysis (IVT) bridging to mechanical thrombectomy in patients with acute ischemic stroke (AIS) is unknown. The purpose of this meta-analysis was to evaluate the safety and efficacy of tirofiban in IVT bridging to mechanical thrombectomy in acute ischemic stroke.

Methods

We systematically searched PubMed, EMBASE, Web of Science, and The Cochrane Library, CNKI, and Wan Fang databases for randomized controlled trials and observational studies (case-control studies and cohort studies) comparing the tirofiban and non-tirofiban groups in AIS intravenous thrombolysis bridging to mechanical thrombectomy (Published by November 20, 2021). Our primary safety endpoints were symptomatic cerebral hemorrhage (sICH), intracranial hemorrhage (ICH), postoperative re-occlusion, and 3-month mortality; the efficacy endpoints were 3-month favorable functional outcome (MRS ≤ 2) and successful recanalization rate (modified thrombolytic therapy in cerebral infarction (mTICI) 2b or 3).

Results

A total of 7 studies with 1,176 patients were included in this meta-analysis. A comprehensive analysis of the included literature showed that the difference between the tirofiban and non-tirofiban groups in terms of successful recanalization (OR = 1.19, 95% Cl [0.69, 2.03], p = 0.53, I² = 22%) and favorable functional outcome at 3 months (OR = 1.13, 95% Cl [0.81, 1.60], p = 0.47, I² = 17%) in patients with IVT bridging mechanical thrombectomy of AIS was not statistically significant. Also, the differences in the incidence of sICH (OR = 0.97, 95% Cl [0.58, 1.62], p = 0.89) and ICH (OR = 0.83, 95% Cl [0.55, 1.24], p = 0.36) between the two groups were not statistically significant. However, the use of tirofiban during IVT bridging mechanical thrombectomy reduced the rate of postoperative re-occlusion (OR = 0.36, 95% Cl [0.14, 0.91], p = 0.03) and mortality within 3 months (OR = 0.54, 95% Cl [0.33, 0.87], p = 0.01) in patients.

Conclusion

The use of tirofiban during IVT bridging mechanical thrombectomy for AIS does not increase the risk of sICH and ICH in patients and reduces the risk of postoperative re-occlusion and mortality in patients within 3 months. However, this result needs to be further confirmed by additional large-sample, multicenter, prospective randomized controlled trials.

Systematic Review Registration

http://www.crd.york.ac.uk/PROSPERO/, identifier: CRD42022297441.

Cyclo(RGD) peptide-decorated silver nanoparticles with anti-platelet potential for active platelet-rich thrombus targeting

The development of integrated nanomedicine for prevention and early diagnosis of thrombosis is highly significant. Platelet plays a vital role in thrombotic disorders, offering an ideal target for thromboprophylaxis and imaging of thrombi. We herein fabricated cyclo(RGD) peptide-decorated AgNPs (designated cRGD-AgNPs) for active targeting platelet-rich thrombi. In vitro cytotoxicity and hemolysis assays demonstrated that cRGD-AgNPs have acceptable biocompatibility pattern. Both PEG-AgNPs (non-targeted version) and cRGD-AgNPs can inhibit agonist-mediated platelet aggregation, whereas the latter exhibited significant attenuation on platelet activation and adhesion onto collagen and fibrinogen matrix. Furthermore, the superior binding ability of cRGD-AgNPs with platelet-rich thrombus was demonstrated in static/dynamic condition in vitro. In vivo studies revealed that cRGD-AgNPs could actively target thrombi in a mouse model of carotid artery thrombi with favorable safety. Our results here suggest that cRGD-AgNPs with intrinsic anti-platelet potential might be promising nano theranostics for thromboprophylaxis and active thrombus targeting.

Nanobiotechnology approaches for cardiovascular diseases: site-specific targeting of drugs and nanoparticles for atherothrombosis

Atherosclerosis and atherothrombosis, the major contributors to cardiovascular diseases (CVDs), represent the leading cause of death worldwide. Current pharmacological therapies have been associated with side effects or are insufficient at halting atherosclerotic progression effectively. Pioneering work harnessing the passive diffusion or endocytosis properties of nanoparticles and advanced biotechnologies in creating recombinant proteins for site-specific delivery have been utilized to overcome these limitations. Since CVDs are complex diseases, the most challenging aspect of developing site-specific therapies is the identification of an individual and unique antigenic epitope that is only expressed in lesions or diseased areas. This review focuses on the pathological mechanism of atherothrombosis and discusses the unique targets that are important during disease progression. We review recent advances in site-specific therapy using novel targeted drug-delivery and nanoparticle-carrier systems. Furthermore, we explore the limitations and future perspectives of site-specific therapy for CVDs.

Intracranial non-occlusive intraluminal thrombus may indicate underlying etiology of large vessel occlusion in patients undergoing endovascular therapy

BACKGROUND

The underlying etiology of intracranial non-occlusive intraluminal thrombus (iNOT) remains unknown. This study aimed to investigate whether the presence of iNOT can indicate the underlying etiology of large vessel occlusion (LVO) in patients undergoing endovascular therapy (EVT).

METHODS

Among patients who underwent EVT at three comprehensive stroke centers, we included those with intracranial LVO in the anterior circulation. The presence of iNOT was determined by pretreatment DSA. We investigated the association between iNOT and intracranial atherosclerotic stenosis (ICAS) related LVO.

RESULTS

Of 546 patients, 44 (8.1%) had iNOT. Patients with iNOT were younger, had less hypertension, atrial fibrillation, and a history of antiplatelet use. In addition, the involvement of the M1 segment of the middle cerebral artery (MCA) was more frequent. However, they had a lower National Institutes of Health Stroke Scale (NIHSS) score on admission and longer onset to recanalization time compared with patients with no iNOT. In a logistic regression model adjusting for age, sex, atrial fibrillation, smoking, prior antiplatelet and anticoagulant use, intravenous tissue plasminogen activator, NIHSS on admission, number of technical trials, intraprocedural re-occlusion, and the location of LVO (p<0.10 in the univariate analysis), the presence of iNOT was significantly associated with ICAS related LVO (adjusted OR 3.04; 95% CI 1.33 to 6.90; p=0.007).

CONCLUSIONS

The presence of iNOT may reflect an underlying ICAS related LVO in patients undergoing EVT.

Early platelet dysfunction in patients receiving extracorporeal membrane oxygenation is associated with mortality

Extracorporeal membrane oxygenation (ECMO) is used for patients with cardiopulmonary failure and is associated with severe bleeding and poor outcome. Platelet dysfunction may be a contributing factor. The aim of this prospective observational study was to characterize platelet dysfunction and its relation to outcome in ECMO patients. Blood was sampled from thirty ECMO patients at three timepoints. Expression of CD62P, CD63, activated GPIIb/IIIa, GPVI, GPIbα and formation platelet-leukocyte aggregates (PLA) were analyzed at rest and in response to stimulation. Delta granule storage-pool deficiency and secretion defects were also investigated. Fifteen healthy volunteers and ten patients with coronary artery disease served as controls. Results were also compared between survivors and non-survivors. Compared to controls, expression of platelet surface markers, delta granule secretion and formation of PLA was reduced, particularly in response to stimulation. Baseline CD63 expression was higher and activated GPIIb/IIIa expression in response to stimulation was lower in non-survivors on day 1 of ECMO. Logistic regression analysis revealed that these markers were associated with mortality. In conclusion, platelets from ECMO patients are severely dysfunctional predisposing patients to bleeding complications and poor outcome. Platelet dysfunction on day 1 of ECMO detected by the platelet surface markers CD63 and activated GPIIb/IIIa is associated with mortality. CD63 and activated GPIIb/IIIa may therefore serve as novel prognostic biomarkers, but future studies are required to determine their true potential.

Molecular Imaging of Arterial and Venous Thrombosis

Thrombosis contributes to one in four deaths worldwide and is the cause of a large proportion of mortality and morbidity. A reliable and rapid diagnosis of thrombosis will allow for immediate therapy, thereby providing significant benefits to patients. Molecular imaging is a fast-growing and captivating area of research, in both preclinical and clinical applications. Major advances have been achieved by improvements in three central areas of molecular imaging: 1) Better markers for diseases, with increased sensitivity and selectivity; 2) Optimised contrast agents with improved signal to noise ratio; 3) Progress in scanner technologies with higher sensitivity and resolution. Clinically available imaging modalities used for molecular imaging include, magnetic resonance imaging (MRI), X-ray computed tomography (CT), ultrasound, as well as nuclear imaging, such as positron emission tomography (PET) and single photon emission computed tomography (SPECT). In the preclinical imaging field, optical (fluorescence and bioluminescent) molecular imaging has provided new mechanistic insights in the pathology of thromboembolic diseases. Overall, the advances in molecular imaging, driven by the collaboration of various scientific disciplines, have substantially contributed to an improved understanding of thrombotic disease, and raises the exciting prospect of earlier diagnosis and individualised therapy for cardiovascular diseases. As such, these advances hold significant promise to be translated to clinical practice and ultimately to reduce mortality and morbidity in patients with thromboembolic diseases.

Current Strategies for Microbubble-Based Thrombus Targeting: Activation-Specific Epitopes and Small Molecular Ligands

Microbubbles with enhanced ultrasound represent a potentially potent evolution to the administration of a free drug in the treatment of thrombotic diseases. Conformational and expressional changes of several thrombotic biological components during active coagulation provide epitopes that allow site-specific delivery of microbubble-based agents to the thrombus for theranostic purpose. Through the interaction with these epitopes, emerging high-affinity small molecular ligands are able to selectively target the thrombi with tremendous advantages over traditional antibody-based strategy. In this mini-review, we summarize recent novel strategies for microbubble-based targeting of thrombus through epitopes located at activated platelets and fibrin. We also discuss the challenges of current targeting modalities and supramolecular carrier systems for their translational use in thrombotic pathologies.

Safety and Efficacy of Low-Dose Tirofiban Combined With Intravenous Thrombolysis and Mechanical Thrombectomy in Acute Ischemic Stroke: A Matched-Control Analysis From a Nationwide Registry

Purpose: Tirofiban administration to acute ischemic stroke patients undergoing mechanical thrombectomy with preceding intravenous thrombolysis remains controversial. The aim of the current study was to evaluate the safety and efficacy of low-dose tirofiban during mechanical thrombectomy in patients with preceding intravenous thrombolysis.

Methods: Patients with acute ischemic stroke undergoing mechanical thrombectomy and preceding intravenous thrombolysis were derived from “ANGEL-ACT,” a multicenter, prospective registry study. The patients were dichotomized into tirofiban and non-tirofiban groups based on whether tirofiban was administered. Propensity score matching was used to minimize case bias. The primary safety endpoint was symptomatic intracerebral hemorrhage (sICH), defined as an intracerebral hemorrhage (ICH) associated with clinical deterioration as determined by the Heidelberg Bleeding Classification. All ICHs and hemorrhage types were recorded. Clinical outcomes included successful recanalization, dramatic clinical improvement, functional independence, and mortality at the 3-month follow-up timepoint. Successful recanalization was defined as a modified Thrombolysis in Cerebral Ischemia score of 2b or 3. Dramatic clinical improvement at 24 h was defined as a reduction in NIH stroke score of ≥10 points compared with admission, or a score ≤1. Functional independence was defined as a Modified Rankin Scale (mRS) score of 0–2 at 3-months.

Results: The study included 201 patients, 81 in the tirofiban group and 120 in the non-tirofiban group, and each group included 68 patients after propensity score matching. Of the 201 patients, 52 (25.9%) suffered ICH, 15 (7.5%) suffered sICH, and 18 (9.0%) died within 3-months. The median mRS was 3 (0–4), 99 (49.3%) achieved functional independence. There were no statistically significant differences in safety outcomes, efficacy outcomes on successful recanalization, dramatic clinical improvement, or 3-month mRS between the tirofiban and non-tirofiban groups (all p > 0.05). Similar results were obtained after propensity score matching.

Conclusion: In acute ischemic stroke patients who underwent mechanical thrombectomy and preceding intravenous thrombolysis, low-dose tirofiban was not associated with increased risk of sICH or ICH. Further randomized clinical trials are needed to confirm the effects of tirofiban in patients undergoing bridging therapy.

Fibrinogen-mimicking, multiarm nanovesicles for human thrombus-specific delivery of tissue plasminogen activator and targeted thrombolytic therapy

Clinical use of tissue plasminogen activator (tPA) in thrombolytic therapy is limited by its short circulation time and hemorrhagic side effects. Inspired by fibrinogen binding to activated platelets, we report a fibrinogen-mimicking, multiarm nanovesicle for thrombus-specific tPA delivery and targeted thrombolysis. This biomimetic system is based on the lipid nanovesicle coated with polyethylene glycol (PEG) terminally conjugated with a cyclic RGD (cRGD) peptide. Our experiments with human blood demonstrated its highly selective binding to activated platelets and efficient tPA release at a thrombus site under both static and physiological flow conditions. Its clot dissolution time in a microfluidic system was comparable to that of free tPA. Furthermore, we report a purpose-built computational model capable of simulating targeted thrombolysis of the tPA-loaded nanovesicle and with a potential in predicting the dynamics of thrombolysis in physiologically realistic scenarios. This combined experimental and computational work presents a promising platform for development of thrombolytic nanomedicines.

Exogenous Integrin αIIbβ3 Inhibitors Revisited: Past, Present and Future Applications

The integrin αIIbβ3 is the most abundant integrin on platelets. Upon platelet activation, the integrin changes its conformation (inside-out signalling) and outside-in signalling takes place leading to platelet spreading, platelet aggregation and thrombus formation. Bloodsucking parasites such as mosquitoes, leeches and ticks express anticoagulant and antiplatelet proteins, which represent major sources of lead compounds for the development of useful therapeutic agents for the treatment of haemostatic disorders or cardiovascular diseases. In addition to hematophagous parasites, snakes also possess anticoagulant and antiplatelet proteins in their salivary glands. Two snake venom proteins have been developed into two antiplatelet drugs that are currently used in the clinic. The group of proteins discussed in this review are disintegrins, low molecular weight integrin-binding cysteine-rich proteins, found in snakes, ticks, leeches, worms and horseflies. Finally, we highlight various oral antagonists, which have been tested in clinical trials but were discontinued due to an increase in mortality. No new αIIbβ3 inhibitors are developed since the approval of current platelet antagonists, and structure-function analysis of exogenous disintegrins could help find platelet antagonists with fewer adverse side effects.

Advances in the Management of Acute Venous Thromboembolism and New Therapeutic Agents

Important advances in the understanding and management of venous thromboembolism (VTE) have enhanced our ability to diagnose, prevent, and treat VTE. In this narrative review, we discuss how recent advances in the understanding and management of VTE are changing practice, highlight ongoing unmet needs in VTE management, and outline how novel therapeutic targets with little or no influence on hemostasis may help address these unmet needs.

Safety and Efficacy of Tirofiban for Acute Ischemic Stroke Patients With Large Artery Atherosclerosis Stroke Etiology Undergoing Endovascular Therapy

Objective: To investigate the safety and efficacy of tirofiban in acute ischemic stroke (AIS) patients with large artery atherosclerosis (LAA) stroke etiology receiving endovascular therapy (EVT).

Methods: In this multi-center prospective study, patients who were considered to have an indication received a low dose intra-arterial bolus (0.25–1 mg) of tirofiban. The safety and efficacy outcomes at 90-day follow-ups included symptomatic intracranial hemorrhage (sICH), recanalization rate, functional outcome, and mortality.

Results: Among the 649 AIS patients with LAA, those in the tirofiban group (n = 244) showed higher systolic blood pressure (BP) and NIHSS score on admission, puncture-to-recanalization time, lower frequency of intravenous thrombolysis and intra-arterial thrombolysis, higher frequency of antiplatelet, heparinization, mechanical stent retrieval, aspiration, balloon angioplasty, and more retrieval times compared with those in the non-tirofiban group (n = 405) (all P < 0.05). Tirofiban was found to be associated with superior clinical outcomes in anterior circulation stroke and major stroke patients [adjusted odds ratio (OR) = 2.163, 95% confidence interval (CI) = 1.130–4.140, P = 0.02 and adjusted OR = 2.361, 95% CI = 1.326–4.202, P = 0.004, respectively] and a lower risk of mortality at 90-day follow-ups (adjusted OR = 0.159, 95% CI = 0.042–0.599, P = 0.007 and adjusted OR = 0.252, 95% CI = 0.103–0.621, P = 0.003, respectively). There was no significant difference in sICH between the two groups.

Conclusions: Tirofiban in AIS patients with LAA undergoing EVT is safe and may benefit the functional outcomes in anterior circulation and major stroke patients and showed a trend for reduced mortality.

Targeted nano-delivery strategies for facilitating thrombolysis treatment in ischemic stroke

Ischemic stroke is one of the major causes of severe disability and death worldwide. It is mainly caused by a sudden reduction in cerebral blood flow due to obstruction of the supplying vessel by thrombi and subsequent initiation of a complex cascade of pathophysiological changes, which ultimately lead to brain ischemia and even irreversible infarction. Thus, timely and effective thrombolysis therapy remains a mainstay for acute ischemic stroke treatment. Tissue plasminogen activator (tPA), the only thrombolytic agent approved globally, provides substantial benefits by exerting a fibrinolysis effect, recovering the blood supply in occluded vessels and, thereby, salvaging the ischemic tissue. However, the clinical application of tPA was limited because of a few unsolved issues, such as a narrow therapeutic window, hemorrhagic complications, and limited thrombolytic efficacy, especially, for large thrombi. With the prosperous development of nanotechnology, a series of targeted delivery strategies and nanocomposites have been extensively investigated for delivering thrombolytic agents to facilitate thrombolysis treatment. Excitingly, numerous novel attempts have been reported to be effective in extending the half-life, targeting the thrombus site, and improving the thrombolytic efficacy in preclinical models. This article begins with a brief introduction to ischemic stroke, then describes the current state of thrombolysis treatment and, finally, introduces the application of various nanotechnology-based strategies for targeted delivery of thrombolytic agents. Representative studies are reviewed according to diverse strategies and nano-formulations, with the aim of providing integrated and up-to-date information and to improve the development of thrombolysis treatment for stroke patients.

The Application of Tirofiban in the Endovascular Treatment of Acute Ischemic Stroke: A Meta-Analysis

OBJECTIVE

The purpose of this meta-analysis is to evaluate the safety and efficacy of tirofiban during endovascular treatment (EVT) for acute ischemic stroke (AIS) patients.

METHODS

We systematically searched PubMed, Embase, Web of Science, and CENTRAL (Cochrane Central Register of Controlled Trials) databases for randomized controlled trials and cohort studies (published before May 1, 2020; no language restrictions) comparing tirofiban administration to blank control during EVT in patients with AIS. Our primary end points were the 3-month functional outcome, recanalization rate, symptomatic intracerebral hemorrhage, and 3-month mortality.

RESULTS

The incidence of 3-month modified Rankin Scale (mRS) 0-2 score of the tirofiban group was higher than that of the control group (odds ratio [OR] = 1.27, 95% CI [1.09, 1.48], p = 0.002) with heterogeneity (I2 = 34%, p = 0.11). Data pooled from the 6 studies describing the details of retriever stent in EVT revealed that tirofiban was associated with higher incidence of 3-month mRS 0-2 score (OR = 1.48, 95% CI [1.11, 1.96], p = 0.007). The recanalization rate was higher in the tirofiban group compared to the control group (OR = 1.66, 95% CI [1.16, 2.39], p = 0.006). There were no statistically significant differences in the incidence of symptomatic intracranial hemorrhage (OR = 0.97, 95% CI [0.73, 1.31], p = 0.86) and intracranial hemorrhage (OR = 1.08, 95% CI [0.59, 1.97], p = 0.80) between tirofiban and non-tirofiban group. Besides, the tirofiban administration was associated with lower mortality (OR = 0.75, 95% CI [0.62, 0.91], p = 0.003).

CONCLUSIONS

The application of tirofiban in EVT of AIS may improve functional outcomes and reduce mortality at 3 months. Besides, tirofiban does not seem to increase the risk of symptomatic intracranial hemorrhage and intracranial hemorrhage, either in the anterior or posterior circulation stroke.

Phage Display Derived Monoclonal Antibodies: From Bench to Bedside

Monoclonal antibodies (mAbs) have become one of the most important classes of biopharmaceutical products, and they continue to dominate the universe of biopharmaceutical markets in terms of approval and sales. They are the most profitable single product class, where they represent six of the top ten selling drugs. At the beginning of the 1990s, an in vitro antibody selection technology known as antibody phage display was developed by John McCafferty and Sir. Gregory Winter that enabled the discovery of human antibodies for diverse applications, particularly antibody-based drugs. They created combinatorial antibody libraries on filamentous phage to be utilized for generating antigen specific antibodies in a matter of weeks. Since then, more than 70 phage–derived antibodies entered clinical studies and 14 of them have been approved. These antibodies are indicated for cancer, and non-cancer medical conditions, such as inflammatory, optical, infectious, or immunological diseases. This review will illustrate the utility of phage display as a powerful platform for therapeutic antibodies discovery and describe in detail all the approved mAbs derived from phage display.

Safety and efficacy of tirofiban combined with endovascular therapy compared with endovascular therapy alone in acute ischemic stroke: a meta-analysis

Endovascular treatment (EVT) has been widely used for treating acute ischemic stroke (AIS). However, the safety and efficacy of treating AIS with tirofiban combined with EVT remain controversial. Therefore, we conducted a meta-analysis to evaluate this treatment. Randomized controlled trials and cohort studies that compared treatment with tirofiban combined with EVT and EVT alone were included in our meta-analysis. Those published from inception to March 31, 2020, were searched using the PubMed, Web of Science, Embase, and Cochrane Library databases. Safety was assessed based on symptomatic intracranial hemorrhage (sICH) incidence and 3-month mortality. Efficacy was assessed based on modified Rankin Scale (mRS) scores at 3 months post-EVT and recanalization rates. Data were analyzed using either the random-effects or fixed-effects model based on the heterogeneity of studies. In total, one RCT, six prospective studies, and four retrospective studies (2387 AIS cases) were assessed. Our meta-analysis showed that tirofiban combined with EVT did not increase sICH risk (RR, 1.06; 95%CI, 0.79 to 1.42; P = 0.72) and 3-month mortality (RR, 0.87; 95%CI, 0.74 to 1.04; P = 0.12). Recanalization rates were not significantly different between patients treated with tirofiban combined with EVT and those treated with EVT alone (RR, 1.04; 95%CI, 1.00 to 1.08; P = 0.07), but tirofiban combined with EVT was significantly associated with favorable functional outcomes (mRS score, 0-2) in AIS patients (RR, 1.13; 95%CI, 1.02 to 1.25; P = 0.02). Tirofiban combined with EVT appears to be safe and potentially effective in treating AIS.

Molecular magnetic resonance imaging of activated platelets allows noninvasive detection of early myocarditis in mice

MRI sensitivity for diagnosis and localization of early myocarditis is limited, although it is of central clinical interest. The aim of this project was to test a contrast agent targeting activated platelets consisting of microparticles of iron oxide (MPIO) conjugated to a single-chain antibody directed against ligand-induced binding sites (LIBS) of activated glycoprotein IIb/IIIa (= LIBS-MPIO). Myocarditis was induced by subcutaneous injection of an emulsion of porcine cardiac myosin and complete Freund’s adjuvant in mice. 3D 7 T in-vivo MRI showed focal signal effects in LIBS-MPIO injected mice 2 days after induction of myocarditis, whereas in control-MPIO injected mice no signal was detectable. Histology confirmed CD41-positive staining, indicating platelet involvement in myocarditis in mice as well as in human specimens with significantly higher LIBS-MPIO binding compared to control-MPIO in both species. Quantification of the myocardial MRI signal confirmed a signal decrease after LIBS-MPIO injection and significant less signal in comparison to control-MPIO injection. These data show, that platelets are involved in inflammation during the course of myocarditis in mice and humans. They can be imaged non-invasively with LIBS-MPIO by molecular MRI at an early time point of the inflammation in mice, which is a valuable approach for preclinical models and of interest for both diagnostic and prognostic purposes.

Conformation-Specific Blockade of αIIbβ3 by a Non-RGD Peptide to Inhibit Platelet Activation without Causing Significant Bleeding and Thrombocytopenia

Bleeding and thrombocytopenia to readministration are the most serious side effects of clinical integrin αIIbβ3 antagonists such as RGD-containing peptides. Here we show that a non-RGD peptide ZDPI, identified from skin secretions of Amolops loloensis, inhibited platelet aggregation induced by agonists, such as adenosine diphosphate, collagen, arachidonic acid, PAR1AP, and integrin αIIbβ3 allosteric activator, and reduces soluble fibrinogen binding to activated platelets without perturbing adhesion numbers on immobilized fibrinogen. Further study showed that ZDPI preferred to bind to the active conformation of integrin αIIbβ3, and thus inhibited c-Src-mediated integrin signaling transduction. In contrast to currently used clinical blockers of integrin αIIbβ3, which are all conformation-unspecific blockers, ZDPI conformation specifically binds to activated integrin αIIbβ3, subsequently suppressing platelet spreading. In vivo study revealed that ZDPI inhibited carotid arterial thrombosis with limited bleeding and thrombocytopenia. A non-RGD peptide which targets the active conformation of integrin αIIbβ3, such as ZDPI, might be an excellent candidate or template to develop antithrombotics without significant bleeding and thrombocytopenia side effects.

New Antithrombotic Drugs in Acute Coronary Syndrome

In recent years, much progress has been made in the field of antithrombotic drugs in acute coronary syndrome (ACS) treatment, as reflected by the introduction of the more potent P2Y12-inhibitors prasugrel and ticagrelor, and novel forms of concomitant anticoagulation, such as fondaparinux and bivalirudin. However, despite substantial improvements in contemporary ACS treatment, there remains residual ischemic risk in this group and hence the need for even more effective antithrombotic drugs, while balancing antithrombotic efficacy against bleeding risk. This review discusses recently introduced and currently developed antiplatelet and anticoagulant drugs in ACS treatment.