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Temperature affects thrombolytic efficacy using rt-PA and eptifibatide, an in vitro study.

ABSTRACT: The potential for hypothermia as a neuroprotectant during stroke has led to its increase in clinical use. At the same time, combination pharmaceutical therapies for ischemic stroke using recombinant tissue plasminogen activator (rt-PA), and GP IIb-IIIa inhibitors, such as Eptifibatide (Epf?), are under study. However, there is little data on how the reactions triggered by these agents are impacted by temperature. Here, clot lysis during exposure to the combination of rt-PA and Epf is measured in an in vitro human clot model at hypothermic temperatures. The hypothesis is that lytic efficacy of rt-PA and Epf decreases with decreasing temperature. Whole blood clots from 31 volunteers were exposed to rt-PA (0.5??g/mL) and Epf (0.63??g/mL) in human fresh-frozen plasma (rt-PA+Epf?), rt-PA alone in plasma (rt-PA Alone), or to plasma alone (Control), at temperatures from 30°C to 37°C, for 30 minutes. Clot lysis was measured using a microscopic imaging technique; the mean fractional clot loss (FCL) at 30 minutes was used to determine lytic efficacy. Temperature had a significant impact on FCL in clots exposed to rt-PA+Epf, with the FCL being lower at 30°C to 36°C than at 37°C. The FCL remained significantly higher for rt-PA+Epf–treated clots than Controls regardless of temperature, with the exception of measurements made at 30°C when no significant differences in the FCL were observed between groups. The use of hypothermia as a neuroprotectant may negatively impact the therapeutic benefit of thrombolytic agents.

SUBMITTER: Meunier JM

PROVIDER: S-EPMC3621317 | biostudies-other | 2012 Sep

REPOSITORIES: biostudies-other

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Temperature affects thrombolytic efficacy using rt-PA and eptifibatide, an in vitro study.

Meunier Jason M JM Chang Wan-Tsu W WT Bluett Brent B Wenker Evan E Lindsell Christopher J CJ Shaw George J GJ

Therapeutic hypothermia and temperature management 20120901 3

The potential for hypothermia as a neuroprotectant during stroke has led to its increase in clinical use. At the same time, combination pharmaceutical therapies for ischemic stroke using recombinant tissue plasminogen activator (rt-PA), and GP IIb-IIIa inhibitors, such as Eptifibatide (Epf ), are under study. However, there is little data on how the reactions triggered by these agents are impacted by temperature. Here, clot lysis during exposure to the combination of rt-PA and Epf is measured in ...[more]

PMID: 23667777

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Project description:Background: Hemorrhagic transformation, neurotoxicity, short treatment time windows, and other defects are considered as the major limitations for the thrombolytic therapy. This study is devoted to figure out whether Danhong injection (DHI) combined with tissue-plasminogen activator (t-PA) could extend the treatment time windows and ameliorate brain injury, hemorrhagic complication and BBB disruption after focal embolic stroke. Methods:In vitro, the combined concentrations of DHI and t-PA were added to wells reacted with plasminogen and D-Val-Leu-Lys-AMC. The optimum ratio of the combination of DHI plus t-PA was explored by detecting relative fluorescent. In vivo experiments, we firstly investigated the optimal dose of t-PA and Danhong injection for focal embolic stroke. The neurological deficit score, infarct volume and brain edema were assessed. Secondly, we proved that the combination group extended the thrombolytic window for treatment of focal embolic stroke. The neurological deficit score, infarct volume, brain edema and hemorrhagic complication were assessed, while levels of BAX, Bcl-2 and caspase-3 in brain tissue were analyzed by real-time polymerase chain reaction. Finally, to ask whether combination therapy with DHI plus t-PA protected the blood-brain barrier in a rat model of focal embolic stroke, neurological deficit score, ELISA, RT-PCR, western blot and fluorescence were used to detect the indicators of blood-brain barrier, such as tight junction protein, blood-brain barrier permeability and related gene expression. Results:In vitro, plasmin activity assays showed that the combination of t-PA with DHI at about 1:1.6 w/v ratio increased by almost 1.4-fold the plasmin-generating capability of t-PA. In vivo experiments, the results showed that the combination of Danhong injection (4 mL/kg) and t-PA (2.5 mg/kg) could extend the t-PA treatment time windows to 4.5 h. And the combination t-PA (2.5 mg/kg) with DHI (4 mL/kg) ameliorated neurological score, cerebral infarction, brain edema, brain hemorrhage, and BBB disruption. Conclusion: Combination therapy with Danhong injection (4 mL/kg) plus t-PA (2.5 mg/kg) could extend the t-PA treatment time windows to 4.5 h, ameliorate BBB disruption, reduce infarction, brain swelling and hemorrhage after ischemic stroke.

Project description:Background and purposeThe recanalization rate after intravenous thrombolysis (IVT) is not enough and there is still the possibility of re-occlusion. We aim to investigate the effectiveness and safety of infusing tirofiban after IVT.MethodsWe performed a prospective controlled study of 60 patients with acute non-cardiogenic ischemic stroke who were hospitalized in Yantai Yuhuangding Hospital from January 2018 to December 2019. The patients were divided into 2 groups: those who received tirofiban for 24 h after IVT (rt-PA + T group) and those who did not receive postprocedural intravenous tirofiban (rt-PA group). The rt-PA + T group received low-dose rt-PA (0.6 mg/kg). The rt-PA group received standard dose rt-PA (0.9 mg/kg). The main outcome measure were safety, included the symptomatic intracranial hemorrhage (sICH), any ICH, severe systemic bleeding, and mortality. The secondary outcome measure is curative efficacy which were evaluated by the 7d-NIHSS score and functional outcomes at 90 days. During hospitalization, the deterioration of neurological function was recorded.ResultsAll patients completed the follow-up with complete data, there were 30 patients in each of groups. The general characteristics between the two group patients had no statistically significant differences. Compared with the rt-PA + T group and the rt-PA group, in terms of safety, the rates of the sICH, severe systemic bleeding, and mortality in both groups were 0, and there was no statistically significant difference in the rates of any ICH between the two groups (10.0% vs. 3.3%, P = 0.306). In terms of efficacy, the rate of the early neurological deterioration events (END) was no statistical significance (0 vs. 6.6%, P = 0.246). There was no significant difference in the NIHSS score between the two groups before the IVT, and also at 24 h, however, the 7d-NIHSS score was lower in the rt-PA + T group compared with the rt-PA group (2.33 ± 1.85 vs. 4.80 ± 4.02, P = 0.004). At 90 days, 83.3% of patients in the rt-PA + T group had favorable functional outcomes compared with 60.0% of patients in the rt-PA group (P = 0.045).ConclusionsLow-dose rt-PA combined with tirofiban in acute non-cardiogenic ischemic stroke did not increase the risk of ICH, and mortality, and it was associated with neurological improvement.Trial registrationThe trial has been registered at the ChiCTR and identified as ChiCTR1800014666 (28/01/2018).

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Temperature affects thrombolytic efficacy using rt-PA and eptifibatide, an in vitro study.

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Temperature affects thrombolytic efficacy using rt-PA and eptifibatide, an in vitro study.

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