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Direct Imaging of Cerebral Thromboemboli Using Computed Tomography and Fibrin-targeted Gold Nanoparticles.

Kim JY, Ryu JH, Schellingerhout D, Sun IC, Lee SK, Jeon S, Kim J, Kwon IC, Nahrendorf M, Ahn CH, Kim K, Kim DE - Theranostics (2015)

Bottom Line: Glycol-chitosan-coated gold nanoparticles (GC-AuNPs) were synthesized and conjugated to fibrin-targeting peptides, forming fib-GC-AuNP.This targeted imaging agent and non-targeted control agent were characterized in vitro and in vivo in C57Bl/6 mice (n = 107) with FeCl3-induced carotid thrombosis and/or embolic ischemic stroke.Fibrin-binding capacity was superior with fib-GC-AuNPs compared to GC-AuNPs, with thrombi visualized as high density on microCT (mCT). mCT imaging using fib-GC-AuNP allowed the prompt detection and quantification of cerebral thrombi, and monitoring of tPA-mediated thrombolytic effect, which reflected histological stroke outcome.

View Article: PubMed Central - PubMed

Affiliation: 1. Molecular Imaging and Neurovascular Research Laboratory, Dongguk University College of Medicine, Goyang, South Korea;

ABSTRACT
Computed tomography (CT) is the current standard for time-critical decision-making in stroke patients, informing decisions on thrombolytic therapy with tissue plasminogen activator (tPA), which has a narrow therapeutic index. We aimed to develop a CT-based method to directly visualize cerebrovascular thrombi and guide thrombolytic therapy. Glycol-chitosan-coated gold nanoparticles (GC-AuNPs) were synthesized and conjugated to fibrin-targeting peptides, forming fib-GC-AuNP. This targeted imaging agent and non-targeted control agent were characterized in vitro and in vivo in C57Bl/6 mice (n = 107) with FeCl3-induced carotid thrombosis and/or embolic ischemic stroke. Fibrin-binding capacity was superior with fib-GC-AuNPs compared to GC-AuNPs, with thrombi visualized as high density on microCT (mCT). mCT imaging using fib-GC-AuNP allowed the prompt detection and quantification of cerebral thrombi, and monitoring of tPA-mediated thrombolytic effect, which reflected histological stroke outcome. Furthermore, recurrent thrombosis could be diagnosed by mCT without further nanoparticle administration for up to 3 weeks. fib-GC-AuNP-based direct cerebral thrombus imaging greatly enhance the value and information obtainable by regular CT, has multiple uses in basic / translational vascular research, and will likely allow personalized thrombolytic therapy in clinic by a) optimizing tPA-dosing to match thrombus burden, b) enabling the rational triage of patients to more radical therapies such as endovascular clot-retrieval, and c) potentially serving as a theranostic platform for targeted delivery of concurrent thrombolysis.

No MeSH data available.


Related in: MedlinePlus

Targeted fib-GC-AuNP mCT imaging allows a prompt and quantitative assessment of the location, amount, and tissue plasminogen activator-mediated lysis of cerebral thromboemboli. A and B, Representative serial mCT thrombus images acquired at baseline (5 minutes after intravenous injection of fib-GC-AuNPs and 1 hour after the embolic stroke), and 3 and 24 hours after tissue plasminogen activator (tPA) treatment. Direct thrombus imaging permits the localization and quantification of cerebral thrombi in the circle of Willis. Follow-up mCT imaging shows no change in the thrombus with saline treatment. However, treatment with tPA, which was initiated after the baseline imaging (total dose of 24 mg/kg tPA administered as a 60 μL bolus injection followed by 540 μL continuous infusion over 30 minutes), shows the dissolution of the thrombus (arrow-heads on B) at 3 and 24 hours. This demonstrates that thrombus marking can allow therapeutic monitoring of thrombolysis. Infarct size on 2,3,5-triphenyl-tetrazolium chloride (TTC) staining (rightmost panels of A and B), performed after the last imaging session, shows a corresponding reduction in the amount of brain infarcted. C, Grouped quantification data for all animals (n = 3 / group). D, A strong correlation between the thrombus areas at 24 hours and the final infarct size at 24 hours. Bar graphs show mean ± SEM. *P < 0.05, repeated measures ANOVA with post-hoc Mann-Whitney tests (vs. baseline) in B, and Mann-Whiney test between the saline and tPA groups in C. Pearson correlation analysis was used to calculate the R2 and P value in D. Scale Bars = 2 mm.
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Figure 5: Targeted fib-GC-AuNP mCT imaging allows a prompt and quantitative assessment of the location, amount, and tissue plasminogen activator-mediated lysis of cerebral thromboemboli. A and B, Representative serial mCT thrombus images acquired at baseline (5 minutes after intravenous injection of fib-GC-AuNPs and 1 hour after the embolic stroke), and 3 and 24 hours after tissue plasminogen activator (tPA) treatment. Direct thrombus imaging permits the localization and quantification of cerebral thrombi in the circle of Willis. Follow-up mCT imaging shows no change in the thrombus with saline treatment. However, treatment with tPA, which was initiated after the baseline imaging (total dose of 24 mg/kg tPA administered as a 60 μL bolus injection followed by 540 μL continuous infusion over 30 minutes), shows the dissolution of the thrombus (arrow-heads on B) at 3 and 24 hours. This demonstrates that thrombus marking can allow therapeutic monitoring of thrombolysis. Infarct size on 2,3,5-triphenyl-tetrazolium chloride (TTC) staining (rightmost panels of A and B), performed after the last imaging session, shows a corresponding reduction in the amount of brain infarcted. C, Grouped quantification data for all animals (n = 3 / group). D, A strong correlation between the thrombus areas at 24 hours and the final infarct size at 24 hours. Bar graphs show mean ± SEM. *P < 0.05, repeated measures ANOVA with post-hoc Mann-Whitney tests (vs. baseline) in B, and Mann-Whiney test between the saline and tPA groups in C. Pearson correlation analysis was used to calculate the R2 and P value in D. Scale Bars = 2 mm.

Mentions: As shown in the representative mice, one hour after embolic stroke and 5 minutes after intravenous injection of fib-GC-AuNPs, mCT thrombus imaging allows the localization and quantification of cerebral thromboemboli (Figure 5). In contrast to saline treatment (n = 3), tPA treatment (n = 3) reduced thrombus area significantly at 3 and 24 hours. This was significant in terms of biological outcomes, as shown by TTC staining-measured final infarct size at 24 hours: smaller in the tPA group animals than for the saline group animals. Furthermore, thrombus areas at 24 hours showed a significant linear correlation with the final infarct size (P < 0.01, R2 = 0.97).


Direct Imaging of Cerebral Thromboemboli Using Computed Tomography and Fibrin-targeted Gold Nanoparticles.

Kim JY, Ryu JH, Schellingerhout D, Sun IC, Lee SK, Jeon S, Kim J, Kwon IC, Nahrendorf M, Ahn CH, Kim K, Kim DE - Theranostics (2015)

Targeted fib-GC-AuNP mCT imaging allows a prompt and quantitative assessment of the location, amount, and tissue plasminogen activator-mediated lysis of cerebral thromboemboli. A and B, Representative serial mCT thrombus images acquired at baseline (5 minutes after intravenous injection of fib-GC-AuNPs and 1 hour after the embolic stroke), and 3 and 24 hours after tissue plasminogen activator (tPA) treatment. Direct thrombus imaging permits the localization and quantification of cerebral thrombi in the circle of Willis. Follow-up mCT imaging shows no change in the thrombus with saline treatment. However, treatment with tPA, which was initiated after the baseline imaging (total dose of 24 mg/kg tPA administered as a 60 μL bolus injection followed by 540 μL continuous infusion over 30 minutes), shows the dissolution of the thrombus (arrow-heads on B) at 3 and 24 hours. This demonstrates that thrombus marking can allow therapeutic monitoring of thrombolysis. Infarct size on 2,3,5-triphenyl-tetrazolium chloride (TTC) staining (rightmost panels of A and B), performed after the last imaging session, shows a corresponding reduction in the amount of brain infarcted. C, Grouped quantification data for all animals (n = 3 / group). D, A strong correlation between the thrombus areas at 24 hours and the final infarct size at 24 hours. Bar graphs show mean ± SEM. *P < 0.05, repeated measures ANOVA with post-hoc Mann-Whitney tests (vs. baseline) in B, and Mann-Whiney test between the saline and tPA groups in C. Pearson correlation analysis was used to calculate the R2 and P value in D. Scale Bars = 2 mm.
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Figure 5: Targeted fib-GC-AuNP mCT imaging allows a prompt and quantitative assessment of the location, amount, and tissue plasminogen activator-mediated lysis of cerebral thromboemboli. A and B, Representative serial mCT thrombus images acquired at baseline (5 minutes after intravenous injection of fib-GC-AuNPs and 1 hour after the embolic stroke), and 3 and 24 hours after tissue plasminogen activator (tPA) treatment. Direct thrombus imaging permits the localization and quantification of cerebral thrombi in the circle of Willis. Follow-up mCT imaging shows no change in the thrombus with saline treatment. However, treatment with tPA, which was initiated after the baseline imaging (total dose of 24 mg/kg tPA administered as a 60 μL bolus injection followed by 540 μL continuous infusion over 30 minutes), shows the dissolution of the thrombus (arrow-heads on B) at 3 and 24 hours. This demonstrates that thrombus marking can allow therapeutic monitoring of thrombolysis. Infarct size on 2,3,5-triphenyl-tetrazolium chloride (TTC) staining (rightmost panels of A and B), performed after the last imaging session, shows a corresponding reduction in the amount of brain infarcted. C, Grouped quantification data for all animals (n = 3 / group). D, A strong correlation between the thrombus areas at 24 hours and the final infarct size at 24 hours. Bar graphs show mean ± SEM. *P < 0.05, repeated measures ANOVA with post-hoc Mann-Whitney tests (vs. baseline) in B, and Mann-Whiney test between the saline and tPA groups in C. Pearson correlation analysis was used to calculate the R2 and P value in D. Scale Bars = 2 mm.
Mentions: As shown in the representative mice, one hour after embolic stroke and 5 minutes after intravenous injection of fib-GC-AuNPs, mCT thrombus imaging allows the localization and quantification of cerebral thromboemboli (Figure 5). In contrast to saline treatment (n = 3), tPA treatment (n = 3) reduced thrombus area significantly at 3 and 24 hours. This was significant in terms of biological outcomes, as shown by TTC staining-measured final infarct size at 24 hours: smaller in the tPA group animals than for the saline group animals. Furthermore, thrombus areas at 24 hours showed a significant linear correlation with the final infarct size (P < 0.01, R2 = 0.97).

Bottom Line: Glycol-chitosan-coated gold nanoparticles (GC-AuNPs) were synthesized and conjugated to fibrin-targeting peptides, forming fib-GC-AuNP.This targeted imaging agent and non-targeted control agent were characterized in vitro and in vivo in C57Bl/6 mice (n = 107) with FeCl3-induced carotid thrombosis and/or embolic ischemic stroke.Fibrin-binding capacity was superior with fib-GC-AuNPs compared to GC-AuNPs, with thrombi visualized as high density on microCT (mCT). mCT imaging using fib-GC-AuNP allowed the prompt detection and quantification of cerebral thrombi, and monitoring of tPA-mediated thrombolytic effect, which reflected histological stroke outcome.

View Article: PubMed Central - PubMed

Affiliation: 1. Molecular Imaging and Neurovascular Research Laboratory, Dongguk University College of Medicine, Goyang, South Korea;

ABSTRACT
Computed tomography (CT) is the current standard for time-critical decision-making in stroke patients, informing decisions on thrombolytic therapy with tissue plasminogen activator (tPA), which has a narrow therapeutic index. We aimed to develop a CT-based method to directly visualize cerebrovascular thrombi and guide thrombolytic therapy. Glycol-chitosan-coated gold nanoparticles (GC-AuNPs) were synthesized and conjugated to fibrin-targeting peptides, forming fib-GC-AuNP. This targeted imaging agent and non-targeted control agent were characterized in vitro and in vivo in C57Bl/6 mice (n = 107) with FeCl3-induced carotid thrombosis and/or embolic ischemic stroke. Fibrin-binding capacity was superior with fib-GC-AuNPs compared to GC-AuNPs, with thrombi visualized as high density on microCT (mCT). mCT imaging using fib-GC-AuNP allowed the prompt detection and quantification of cerebral thrombi, and monitoring of tPA-mediated thrombolytic effect, which reflected histological stroke outcome. Furthermore, recurrent thrombosis could be diagnosed by mCT without further nanoparticle administration for up to 3 weeks. fib-GC-AuNP-based direct cerebral thrombus imaging greatly enhance the value and information obtainable by regular CT, has multiple uses in basic / translational vascular research, and will likely allow personalized thrombolytic therapy in clinic by a) optimizing tPA-dosing to match thrombus burden, b) enabling the rational triage of patients to more radical therapies such as endovascular clot-retrieval, and c) potentially serving as a theranostic platform for targeted delivery of concurrent thrombolysis.

No MeSH data available.


Related in: MedlinePlus