Tirofiban induces VEGF production and stimulates migration and proliferation of endothelial cells

Risk Factors, Antithrombotic Management, and Long-Term Outcomes of Patients Undergoing Endovascular Treatment of Unruptured Intracranial Aneurysms

BACKGROUND

 Patients receiving endovascular treatment for unruptured intracranial aneurysms (UIAs) face varying risks and benefits with antithrombotic management. This study aimed to evaluate the perioperative and long-term effects of antithrombotic strategies, identify the populations that would benefit, and explore the predictive factors affecting the long-term outcomes.

METHODS

 UIA patients undergoing endovascular treatment including stent-assisted coiling or flow diversion between June 2019 and June 2022 were enrolled. We compared perioperative and long-term complications between tirofiban and dual antiplatelet therapy groups. Optimal candidates for each antithrombotic treatment were identified using multivariate logistic regression. Nomograms were developed to determine the significant predictors for thromboembolic complications during follow-up.

RESULTS

 Among 181 propensity-score matched pairs, the tirofiban group showed a trend toward a lower rate of thromboembolic complications than the DAPT group without elevating major bleeding risk in either period. Homocysteine (Hcy) level ≥10 μmol/L was a significant independent factor associated with thromboembolic complication in both periods. Subgroup analysis highlighted that in patients with high Hcy levels, tirofiban and sustained antiplatelet treatment for ≥12 months were protective factors, while a history of stroke was an independent risk factor for thromboembolic events in follow-up. Four variables were selected to construct a prognostic nomogram, history of hypertension, prior stroke, Hcy level, and the duration of antiplatelet therapy.

CONCLUSION

 Perioperative low-dose tirofiban and extended antiplatelet therapy demonstrated a favorable trend in long-term outcomes for UIA patients with preoperative Hcy levels ≥10 μmol/L undergoing endovascular treatment. The prognostic model offers reliable risk prediction and guides antithrombotic strategy decisions.

Safety and Efficacy of Tirofiban Bridging Therapy During a Hybrid Carotid Artery Stenting and Off-Pump Coronary Artery Bypass Grafting Surgery: A Single-Center Study

PURPOSE

The optimal perioperative antithrombosis management for carotid artery stenting (CAS) and coronary artery bypass grafting (CABG) hybrid surgeries remains unclear; however, a more aggressive antithrombotic therapy might be required after a hybrid CAS + CABG duo stent-related intimal injury or the use of protamine-neutralizing heparin. This study evaluated the safety and efficacy of tirofiban as a bridging therapy after a hybrid CAS + CABG surgery.

METHODS

Between June 2018 and February 2022, a total of 45 patients undergoing a hybrid CAS + off-pump CABG surgery were divided into either the control group (standard dual antiplatelet therapy postsurgery, n = 27) or the tirofiban group (tirofiban bridging + dual antiplatelet therapy, n = 18). The 30-day outcome was compared between the 2 groups, and the primary end points included stroke, postoperative myocardial infarction, and death.

FINDINGS

Two patients (7.41%) from the control group experienced a stroke. There was a trend toward a lower rate of composite end points, including stroke, postoperative myocardial infarction, and death, within the tirofiban group that did not reach statistical significance (0% vs 11.1%; P = 0.264). The need for a transfusion was similar between the 2 groups (33.33% vs 29.63%; P = 0.793). There were no major bleeding events in the 2 groups.

IMPLICATIONS

Tirofiban bridging therapy was safe, with a trend toward reducing the risk of ischemic events after a hybrid CAS + off-pump CABG surgery. Tirofiban might be a feasible periprocedural bridging protocol in high-risk patients.

FKBP51 plays an essential role in Akt ubiquitination that requires Hsp90 and PHLPP

FKBP51 plays a relevant role in sustaining cancer cells, particularly melanoma. This cochaperone participates in several signaling pathways. FKBP51 forms a complex with Akt and PHLPP, which is reported to dephosphorylate Akt. Given the recent discovery of a spliced FKBP51 isoform, in this paper, we interrogate the canonical and spliced isoforms in regulation of Akt activation. We show that the TPR domain of FKBP51 mediates Akt ubiquitination at K63, which is an essential step for Akt activation. The spliced FKBP51, lacking such domain, cannot link K63-Ub residues to Akt. Unexpectedly, PHLPP silencing does not foster phosphorylation of Akt, and its overexpression even induces phosphorylation of Akt. PHLPP stabilizes levels of E3-ubiquitin ligase TRAF6 and supports K63-ubiquitination of Akt. The interactome profile of FKBP51 from melanoma cells highlights a relevant role for PHLPP in improving oncogenic hallmarks, particularly, cell proliferation.

Key Roles of RGD-Recognizing Integrins During Cardiac Development, on Cardiac Cells, and After Myocardial Infarction

Cardiac cells interact with the extracellular matrix (ECM) proteins through integrin mechanoreceptors that control many cellular events such as cell survival, apoptosis, differentiation, migration, and proliferation. Integrins play a crucial role in cardiac development as well as in cardiac fibrosis and hypertrophy. Integrins recognize oligopeptides present on ECM proteins and are involved in three main types of interaction, namely with collagen, laminin, and the oligopeptide RGD (Arg-Gly-Asp) present on vitronectin and fibronectin proteins. To date, the specific role of integrins recognizing the RGD has not been addressed. In this review, we examine their role during cardiac development, their role on cardiac cells, and their upregulation during pathological processes such as heart fibrosis and hypertrophy. We also examine their role in regenerative and angiogenic processes after myocardial infarction (MI) in the peri-infarct area. Specific targeting of these integrins may be a way of controlling some of these pathological events and thereby improving medical outcomes.

Assay of tirofiban and identification of oxidative impurity in aqueous injection by using UPLC-PDA/QDa detectors

The basic objective of this study is to propose a short, reliable, mass compatible ultra-performance liquid chromatography (UPLC) method to confirm the identity of impurities and to estimate the assay and purity of Tirofiban simultaneously in aqueous injection (5mg/100mL bag). Aqueous formulations are susceptible to oxidation, hence the possible oxidative degradation impurities of Tirofiban were studied in this experiment by using UPLC coupled with photodiode array/Quadrupole Dalton Analyzer (PDA/QDa) detectors. The required separations were achieved in the column: ACQUITY HSS T3 (100×2.1) mm, 1.7μm, operated at 30°C by using 0.02% Triethyl amine (TEA) in water, pH 2.8 with formic acid as solution-A and 0.1% formic acid in 9:1 acetonitrile, water as solution-B. Binary gradient flow is delivered at the rate of 0.5mL/min and the detection of impurities specifically carried out at 227nm using empower3 software. RP-UPLC/PDA with QDa detector was used for the experiment. The method was linear and accurate from the concentrations: 0.04 to 0.38μg/mL for impurity-A and 0.04 to 75μg/mL for Tirofiban. The major unknown degradation impurity generated during the oxidative degradation has been identified as N-oxide derivative (Impurity-B) [(M+H)⁺ 455.1] by using QDa detector operated in an electro spray positive ion mode by applying a voltage of 0.8kV. This method was further validated as per ICH Q2 (R2) guidelines. Hence, the proposed method is said to be a fast, sensitive and comprehensive technique, which could give a clear idea about the assay and impurity profile of Tirofiban injection.

The pleiotropic effects of antithrombotic drugs in the metabolic-cardiovascular-neurodegenerative disease continuum: impact beyond reduced clotting

Antithrombotic drugs are widely used for primary and secondary prevention, as well as treatment of many cardiovascular disorders. Over the past few decades, major advances in the pharmacology of these agents have been made with the introduction of new drug classes as novel therapeutic options. Accumulating evidence indicates that the beneficial outcomes of some of these antithrombotic agents are not solely related to their ability to reduce thrombosis. Here, we review the evidence supporting established and potential pleiotropic effects of four novel classes of antithrombotic drugs, adenosine diphosphate (ADP) P2Y12-receptor antagonists, Glycoprotein IIb/IIIa receptor Inhibitors, and Direct Oral Anticoagulants (DOACs), which include Direct Factor Xa (FXa) and Direct Thrombin Inhibitors. Specifically, we discuss the molecular evidence supporting such pleiotropic effects in the context of cardiovascular disease (CVD) including endothelial dysfunction (ED), atherosclerosis, cardiac injury, stroke, and arrhythmia. Importantly, we highlight the role of DOACs in mitigating metabolic dysfunction-associated cardiovascular derangements. We also postulate that DOACs modulate perivascular adipose tissue inflammation and thus, may reverse cardiovascular dysfunction early in the course of the metabolic syndrome. In this regard, we argue that some antithrombotic agents can reverse the neurovascular damage in Alzheimer's and Parkinson's brain and following traumatic brain injury (TBI). Overall, we attempt to provide an up-to-date comprehensive review of the less-recognized, beneficial molecular aspects of antithrombotic therapy beyond reduced thrombus formation. We also make a solid argument for the need of further mechanistic analysis of the pleiotropic effects of antithrombotic drugs in the future.

Impact of Tirofiban on Serum Troponin Changes in Patients Undergoing Carotid Artery Stenting: A Propensity Matched Analysis

BACKGROUND

The optional periprocedural antithrombotic management for carotid artery stenting (CAS) is still debated.

METHODS

We aimed to compare the procedural and 1-month outlook of patients undergoing CAS with tirofiban as parenteral antiplatelet therapy. We retrospectively compared patients receiving tirofiban during CAS versus those undergoing CAS without tirofiban, using propensity score matching. Ancillary antithrombotic therapy included in all patients aspirin, clopidogrel, and unfractioned heparin. The primary outcome was the change in serum troponin from baseline to postprocedural peak levels. A total of 30 patients undergoing CAS were included, 15 receiving tirofiban on top of heparin and dual oral antiplatelet therapy (DAPT) and 15 receiving only heparin and DAPT. Bail-out use of tirofiban was an exclusion criterion.

RESULTS

Baseline troponin was 3.00 (0.06; 5.20) ng/mL in the tirofiban group vs. 4.6 (0.02; 13.10) ng/mL in the no-tirofiban group (P = 0.229), and postprocedural peak 3.5 (0.06; 5.50) ng/mL vs. 6.30 (0.09; 28.40) ng/mL (P = 0.191). Peak-baseline difference in troponin was lower in the tirofiban group than in the no-tirofiban group: 0.3 (0.00; 1.7) ng/mL vs. 1.3 (0.01; 10.00) ng/mL (P = 0.044); the relative peak-baseline change in troponin was analogously different: 24.3% (0%; 44.7%) vs. 50% (21.3%; 80.0%) (P = 0.039). No case of death, myocardial infarction, stroke, or transient ischemic attack occurred during in-hospital stay or at 1-month follow-up.

CONCLUSIONS

Tirofiban during CAS might provide periprocedural myocardial protection and reduce myocardial injury as determined by serial troponin measurements.

Platelet Function and Risk of Bleeding in Patients With Acute Coronary Syndrome Following Tirofiban Infusion

Aim: To assess platelet (PLT) function and bleeding risks in patients with acute coronary syndrome after tirofiban infusion.

Methods: Patients diagnosed with acute coronary syndrome from May 2016 to February 2018 in the Department of Cardiac Intensive Care Unit, Zhongshan Hospital, were enrolled. They were symmetrically allocated into two groups: tirofiban treatment group or control group (without tirofiban treatment). Blood samples were collected 24 h postoperation for the evaluation of antiplatelet effect of tirofiban. We applied thromboelastography to detect on-treatment PLT reactivity and conducted laboratory tests to assess the risk of bleeding following tirofiban treatment. After discharge, telephone follow-up and outpatient interview were carried out. The primary clinical endpoint was major adverse cardiovascular events, including cardiovascular death, cardiovascular mortality, myocardial infarction, and revascularization for the targeted vascular lesion.

Results: There were a total of 196 patients with acute coronary syndrome after screening with the inclusion criteria and the exclusion criteria. Ninety-eight patients were assigned to receive either tirofiban treatment or control treatment. Patients treated with tirofiban had more coronary lesions and stents implanted compared with the control group (P = 0.000). After tirofiban infusion, inhibition of platelet aggregation induced by thromboxane A₂ and adenosine diphosphate was significantly higher compared to patients without tirofiban infusion (80.3% ± 19.6% vs. 72.6% ± 13.0%, P = 0.002; and 81.0% ± 19.8% vs. 75.4% ± 12.4%, P = 0.020, respectively). There was no significant difference in the reduction of hemoglobin (Hb), hematocrit (Hct), and PLT after administration of tirofiban, compared with baseline (P > 0.05). In addition, no significant differences were identified between the two groups with respect to Hb, Hct, and PLT after tirofiban infusion. However, C-reactive protein level, referred to as an inflammation marker, was significantly lowered after infusion tirofiban compared with the control group (11.9 ± 14.2 vs. 17.9 ± 21.2, P = 0.020). During the 1-year follow-up, the incidence rate of major adverse cardiovascular events remains indiscriminate between the two groups (P = 0.208). The assessments of cardiac biomarkers showed that tirofiban could decrease incidence of procedural myocardial infarction (odds ratio [OR] = 0.250, 95% confidence interval [CI] = 0.067–0.925, P = 0.027). At follow-up, the morbidity of left atrial dilation in tirofiban-treated patients, defined as enlargement of left atrial diameter >40mm, was lower compared to the control group (OR = 0.533, 95% CI = 0.301–0.945, P = 0.031).

Conclusion: Tirofiban infusion could decrease PLT activation in patients with acute coronary syndrome without increasing the risk of bleeding. As a concomitant medication, tirofiban shows no benefit in reducing the occurrence of major adverse cardiovascular events.

Wound healing activity and mechanism of action of antimicrobial and lipopolysaccharide-neutralizing peptides from enzymatic hydrolysates of rice bran proteins

In our previous study, we identified multifunctional cationic peptides from enzymatic hydrolysates of rice bran proteins (RBPs) that have antimicrobial and lipopolysaccharide-neutralizing activities. In this study, we investigated the potential of the peptides RBP-LRR, RBP-EKL, and RBP-SSF to promote proliferation, angiogenesis (tube formation), and migration in human umbilical vein endothelial cells (HUVECs). To determine mechanisms of wound healing actions, angiogenic and migration-promoting activities of these peptides were evaluated following pretreatments of HUVECs with specific inhibitors. In these experiments, the cationic peptides RBP-LRR, RBP-EKL, and RBP-SSF induced cell proliferation at low concentrations of 0.1 μM or 1 μM. Moreover, the three cationic peptides had angiogenic activities at concentrations more than 1 μM in tube formation assays, and their effects were similar to those of LL-37. Subsequent scratch migration assays exhibited that RBP-LRR, RBP-EKL, and RBP-SSF promote wound closure at optimum concentrations of 10, 10, and 0.1 μM, respectively. In further studies, we performed tube formation assays using HUVECs pretreated with SU5416, which inhibits vascular endothelial growth factor (VEGF) receptors, and suggested the possibility that the three cationic peptides induce angiogenesis by activating VEGF receptors. In corresponding scratch migration assays using HUVECs, pretreatment with the proliferation inhibitor mitomycin C did not alter the effects of RBP-LRR and RBP-EKL, and significant contribution to wound closure were mediated by cell migration regardless of proliferation rates. In contrast, RBP-SSF contributed to wound closure exclusively by promoting cell proliferation. The present data indicate that RBP-LRR, RBP-EKL, and RBP-SSF are candidates for use as wound healing agents.

The antimicrobial and anti-endotoxic peptide AmyI-1-18 from rice α-amylase and its [N3L] analog promote angiogenesis and cell migration

In our previous studies, we showed that AmyI-1-18 and its single amino acid-substituted analogs have antimicrobial, anti-inflammatory, and anti-endotoxic activities and cause little or no hemolysis or cytotoxicity. In this study, we investigated the potential of these peptides to promote proliferation, angiogenesis (tube formation), and migration in human umbilical vein endothelial cells (HUVECs). Among five single amino acid-substituted analogs, [N3L]AmyI-1-18 induced cell proliferation in a concentration-dependent manner with similar efficacy to AmyI-1-18. In tube formation assays, AmyI-1-18 and [N3L]AmyI-1-18 had angiogenic activities at 1 μM and their effects were similar to those of LL-37. Moreover, scratch migration assays showed that AmyI-1-18, [N3L]AmyI-1-18, and LL-37 promote cell migration with optimum concentrations of 10, 1, and 0.1 μM, respectively. Subsequently, we performed tube formation assays using HUVECs pretreated with SU5416, which is an inhibitor of vascular endothelial growth factor (VEGF) receptors, and revealed that AmyI-1-18 and [N3L]AmyI-1-18 induce angiogenesis by activating VEGF receptors. Similarly, after pretreating HUVECs with mitomycin C, which inhibits cell proliferation, [N3L]AmyI-1-18 significantly contributed to wound closure in scratch migration assays. Moreover, enhancements of hydrophobicity following substitution of AmyI-1-18 asparagine with leucine led to greater increases in cell migration. The present data indicate that both peptides, particularly [N3L]AmyI-1-18, are candidates for use as wound healing agents.

Targeting neurokinin-3 receptor: a novel anti-angiogenesis strategy for cancer treatment

Angiogenesis is essential for tumor growth and metastasis, controlling angiogenesis is a promising strategy in cancer treatment. However, thus farther severe side effects of anti-angiogenic drugs have been rather demonstrated, stimulating interest in seeking novel targets of anti-angiogenesis. Neurokinin receptors, also known as tachykinin receptors, are usually considered as drug targets due to diverse physiological functions and their tractability. Although Neurokinin B, the selective natural agonist of neurokinin-3 receptor, have been shown to exhibit anti-angiogenesis activity, the effect and mechanism of neurokinin-3 receptor-mediated angiogenesis still remains unclear. In the present study, we demonstrated that [Mephe7]NKB, an analogue of NKB, possess significant anti-angiogenic effect on CAM. Furthermore, by introducing the tumor angiogenesis homing sequence (NGR), we designed and synthesized two novel agonist analogues of NK3R, NK3R-A1 and NK3R-A2. Both of the two analogues exhibit more efficient anti-migration effect on HUVECs by activating NK3R in vitro, and showed potent antitumor activities with no significant side effects in vivo. Taken together, our results illuminated that NK3R might be a potential novel target for the anti-angiogenesis therapy. Notably, NK3R-A1 might be used as a template for the development of the anti-tumor drugs on the basis of the anti-angiogenesis strategy.

Intracoronary administration of tirofiban during percutaneous coronary intervention facilitates patients with acute coronary syndrome

We assessed the efficacy and safety of tirofiban intracoronary versus intravenous administration during percutaneous coronary intervention for patients with acute coronary syndrome. The databases of PubMed, Web of Science, China National Knowledge Infrastructure, and WanFang Database were retrieved. A total of 437 articles were found, according to inclusive and exclusive criteria, 13 of which were finally included. Compared with subjects with intravenous administration, those with intracoronary administration were more likely to reach thrombolysis in myocardial infarction trial grade 3 flow (relative risk = 1.17, 95% confidence interval: 1.11–1.22), improve left ventricular ejection fraction (Standardized mean difference = 0.65, 95% confidence interval: 0.20–1.11). Intracoronary administration resulted in a reduced risk of major adverse cardiovascular events at 30-day follow-up (relative risk = 0.47, 95% confidence interval: 0.34–0.65). However, incidence of bleeding complications was not statistically significant between two groups (relative risk = 0.76, 95% confidence interval: 0.55–1.04). Intracoronary administration of tirofiban can be more effective in increasing coronary blood flow and microvascular perfusion, more effective in improving postoperative myocardial reperfusion, more significantly in reducing the incidence of adverse cardiovascular events at 30-day’s follow-up and improving the prognosis after percutaneous coronary intervention without increasing the risk of bleeding.

Safety and preliminary efficacy of intravenous tirofiban in acute ischemic stroke patient without arterial occlusion on neurovascular imaging studies

BACKGROUND

There has been no effective treatment for acute ischemic stroke (AIS) patients who presented to the Emergency Department >4.5h without a visible arterial occlusion on the neurovascular imaging studies. In this study, we aimed to investigate whether intravenous antiplatelet agent tirofiban was safe and potentially effective in AIS patients who had no visible arterial occlusion and was outside of treatment window for Alteplase. The goal of this study was to collect preliminary data to plan a future phase II study.

METHOD

Twenty-five patients received intravenous tirofiban therapy. The safety outcomes were assessed by the incidence of symptomatic intracerebral hemorrhage (sICH), systematic bleeding and mortality. Efficacy outcomes were evaluated with National Institutes of Health Stroke Scale (NIHSS) score at day 7 (or discharge) and modified Rankin Scale (mRS) at 90days. Outcomes for these patients were compared with a historical age-gender-admission-NIHSS matched cohort treated with aspirin and/or clopidogrel.

RESULTS

The rate of intracerebral hemorrhage, systematic bleedings, and death were not found in both groups. At day 7 or discharge, the neurological function improved significantly in both treatment groups. However, the NIHSS score was lower in tirofiban group compared with the control group (2 vs.3, p=0.045). At 3months, more patients in tirofiban group had favorable outcomes (mRS 0-1) compared with control group (84% vs. 52%; adjusted odds ratio: 10.57; 95% CI: 1.54-72.33; p=0.016).

CONCLUSIONS

Intravenous tirofiban appears to be safe and potentially effective for the ischemic stroke patients with no artery occlusion on neurovascular imaging studies and being out of the window for thrombolytic therapy. A next logic step is to plan for a phase II study.

Intravenous administration of tirofiban versus loading dose of oral clopidogrel for preventing thromboembolism in stent-assisted coiling of intracranial aneurysms

Background Thromboembolic complications after stenting of intracranial aneurysms may be affected by antiplatelet administration. Aims This retrospective study aimed to assess the safety of intravenous tirofiban versus loading dose of oral clopidogrel for preventing thromboembolism in stent-assisted coiling of intracranial aneurysms. Methods From January 2006 to December 2013, 281 patients with cerebral aneurysms were treated with stent-coiling using two antiplatelet strategies in comparison: the initial strategy (a loading dose of ≥300 mg clopidogrel followed by dual antiplatelet, clopidogrel group) and the modified strategy (intravenous administration of tirofiban 8 µg/kg over 3 min followed by a maintenance dose of 0.1 µg/kg/min for 24 h, tirofiban group). The end points were rates of perioperative thromboembolic events and intracranial hemorrhages. Results Thromboembolic events were observed more often in the clopidogrel group (13/120 aneurysms, 10.83%) than the tirofiban group (6/178 aneurysms, 3.37%; P = 0.010), with no increase in the rate of intracranial hemorrhages ( P = 0.164). In the ruptured subgroups, thromboembolic events were significantly fewer in the tirofiban subgroup (5/128, 3.91%) compared with the clopidogrel subgroup (7/53, 13.21%; P = 0.043) with no increase in the rate of hemorrhage ( P = 0.360). Conclusions Intravenous administration of tirofiban is safe in intracranial aneurysms treated with stent-assisted coiling.

Radiolabeled tirofiban - a potential radiopharmaceutical for detection of deep venous thrombosis

Aim

The aim of this study was to investigate the possibility of using ^99mtechnetium (^99mTc)-labeled tirofiban (a reversible antagonist of glycoprotein IIb/IIIa) for detection of deep venous thrombosis (DVT) in rats without causing an antiplatelet effect.

Methods

The ability of in vitro tirofiban to inhibit adenosine 5′-diphosphate (ADP)-induced platelet aggregation was evaluated using optical aggregometer. Binding of ^99mTc-tirofiban to platelets was evaluated. Serum levels of unlabeled (a validated high performance liquid chromatography method) and ^99mTc-tirofiban after single intravenous injection were evaluated in male Wistar rats with or without induced DVT (femoral vein ligation model), and the rats were also subjected to whole body scintigraphy.

Results

Tirofiban in vitro inhibits ADP-induced aggregation of human platelets in a dose- and concentration-dependent manner (10 nM to 2 μM), but only if it is added before ADP and not after ADP. ^99mTc labeling did not affect the ability of tirofiban to bind to either human or rat platelets, nor did it affect tirofiban pharmacokinetics in intact rats or in animals with induced DVT. When ^99mTc-tirofiban was injected to rats after induction of DVT, at a molar dose lower than the one showing only a weak antiaggregatory effect in vitro, whole body scintigraphy indicated localization of ^99mTc-tirofiban around the place of the induced DVT.

Conclusion

^99mTc labeling of tirofiban does not affect its ability to bind to glycoprotein IIb/IIIa or its in vivo pharmacokinetics in rats, either intact or with DVT. A low, nonantiaggregatory dose of ^99mTc-tirofiban may be used to visualize DVT at an early stage.

Tirofiban counteracts endothelial cell apoptosis through the VEGF/VEGFR2/pAkt axis

Tirofiban is used in the treatment of patients with acute coronary syndrome submitted to percutaneous coronary intervention (PCI). We have, previously, shown that tirofiban stimulates VEGF expression and promotes proliferation of endothelial cells. VEGF is a well known inhibitor of endothelial cell apoptosis. TNF-α is a pro-apoptotic cytokine released in the site of a vascular injury, including balloon angioplasty. We thought to investigate whether tirofiban was able to protect endothelial cells from cell death induced by TNF-α. For this study, we used human umbilical vein endothelial cells (HUVEC). Analysis of apoptosis was performed by propidium iodide incorporation, annexin V staining and measure of active caspase 3 levels. Western blot served for a semiquantitative measure of Akt activation, VEGF, and the pro-apoptotic Bim and Bak. Our results show that TNF-α was unable to activate caspase 3 and produce cell death in the presence of tirofiban. Activation of apoptosis was preceded by upregulation of Bim and Bak that resulted decreased after addition of tirofiban. The anti-apoptosis effect of tirofiban was reproduced by VEGF and counteracted by VEGFR2 blockade and the cation chelating agent ethylene glycol tetraacetic acid (EGTA). The use of p-Akt inhibitor, BEZ235,and Akt knockdown, suggested that pAkt mediated the prosurvival effect of tirofiban. In conclusion, tirofiban protects endothelial cells from apoptosis stimulated by TNF-α, due to its ability to stimulate VEGF production.

Safety and efficacy of a new prophylactic tirofiban protocol without oral intraoperative antiplatelet therapy for endovascular treatment of ruptured intracranial aneurysms

BACKGROUND

Coil embolization of intracranial aneurysms is being increasingly used; however, thromboembolic events have become a major periprocedural complication.

OBJECTIVE

To determine the safety and efficacy of prophylactic tirofiban in patients with ruptured intracranial aneurysms.

METHODS

Tirofiban was administered as an intravenous bolus (8.0 μg/kg over 3 min) followed by a maintenance infusion (0.10 μg/kg/min) before stent deployment or after completion of single coiling. Dual oral antiplatelet therapy (loading doses) was overlapped with half the tirofiban dose 2 h before cessation of the tirofiban infusion. Cases of intracranial hemorrhage or thromboembolism were recorded.

RESULTS

Tirofiban was prophylactically used in 221 patients, including 175 (79.19%) who underwent stent-assisted coiling and 46 (20.81%) who underwent single coiling, all in the setting of aneurysmal subarachnoid hemorrhage. Six (2.71%) cases of intracranial hemorrhage occurred, including four (1.81%) tirofiban-related cases and two (0.90%) antiplatelet therapy-related cases. There were two (0.90%) cases of fatal hemorrhage, one related to tirofiban and the other related to dual antiplatelet therapy. Thromboembolic events occurred in seven (3.17%) patients (6 stent-assisted embolization, 1 single coiling), of which one (0.45%) event occurred during stenting and six (2.72%) occurred during intravenous tirofiban maintenance. No thromboembolic events related to dual antiplatelet therapy were found.

CONCLUSIONS

Tirofiban bolus over 3 min followed by maintenance infusion appears to be a safe and efficient prophylactic protocol for the endovascular treatment of ruptured intracranial aneurysms and may be an alternative to intraoperative oral antiplatelet therapy, especially in the case of stent-assisted embolization.

Activation of the Notch signaling pathway promotes neurovascular repair after traumatic brain injury

The Notch signaling pathway plays a key role in angiogenesis and endothelial cell formation, but it remains unclear whether it is involved in vascular repair by endothelial progenitor cells after traumatic brain injury. Therefore, in the present study, we controlled the Notch signaling pathway using overexpression and knockdown constructs. Activation of the Notch signaling pathway by Notch1 or Jagged1 overexpression enhanced the migration, invasiveness and angiogenic ability of endothelial progenitor cells. Suppression of the Notch signaling pathway with Notch1 or Jagged1 siRNAs reduced the migratory capacity, invasiveness and angiogenic ability of endothelial progenitor cells. Activation of the Notch signaling pathway in vivo in a rat model of mild traumatic brain injury promoted neurovascular repair. These findings suggest that the activation of the Notch signaling pathway promotes blood vessel formation and tissue repair after brain trauma.

Salvianolic acid A inhibits endothelial dysfunction and vascular remodeling in spontaneously hypertensive rats

AIMS

Despite the numerous pharmacological agents available for hypertension therapy, hypertension-related microvascular remodeling is not resolved, eventually leading to end-organ damage. The aim of the present study was to investigate the protection of salvianolic acid A (SalA) against microvascular remodeling in vitro and in vivo.

MAIN METHODS

Spontaneously hypertensive rats (SHRs) were administered 2.5, 5 or 10 mg/kg SalA via intraperitoneal injection once a day for 4 weeks. The tail-cuff method was applied to monitor blood pressure; the microvascular structure of the retina was detected by hematoxylin-eosin and immunohistochemical staining; the function of mesenteric arteries was measured by DMT wire myography; endothelial cell proliferation was estimated using the Cell Counting Kit-8; endothelial cell migration was evaluated by wound healing and transwell assay; and endothelial cell integrity was detected by transendothelial electrical resistance and permeability assays.

KEY FINDINGS

Although no antihypertensive effects of SalA were observed, SalA attenuated the microvascular inward remodeling of the retina and improved microvascular function in the mesenteries in vivo. Further cell experiments confirmed the beneficial effects of SalA on the integrity of the endothelial monolayer in vitro.

SIGNIFICANCE

Salvianolic acid A inhibited endothelial dysfunction and vascular remodeling in spontaneously hypertensive rats. Therefore, salvianolic acid A could be a potential drug therapy to prevent further targeted organ damage induced by vascular remodeling.