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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-AuNPs are superior to non-targeted GC-AuNPs in mCT imaging of in situ carotid thrombus. A-D, Representative mCT imaging of in situ carotid thrombosis. Thrombi were formed in C57Bl/6 mice by applying stripes of filter paper (1 × 1 mm2) soaked in 10% FeCl3 to the left distal carotid artery (photographs, upper row). Thirty minutes later, mCT thrombus images (upper row, coronal view; lower row, sagittal view) were acquired 5 minutes after intravenous injection of 200 μL GC-AuNPs (A and B) or fib-GC-AuNPs (C and D) of either a low (2 mg/kg; A-C) or high (20 mg/kg; B and D) concentration. At the low administered doses, fib-GC-AuNPs (D) outperforms GC-AuNPs (C), by more clearly marking the carotid thrombus. The “larger” thrombus in (C) vs. (A) reflects better clot visualization due to more avid binding of the targeted compound. At high administered doses, the areas of thrombus-related hyperdense lesions look similar between the animals injected with either GC-AuNPs (B) or fib-GC-AuNPs (D). E, Grouped quantification data. The above mCT imaging findings from the representative animals are corroborated by the quantification data for all 12 animals (n = 3 / group). At a higher dose (20 mg/kg), both fib-GC-AuNPs and non-targeted GC-AuNPs detected carotid thrombus with equal efficacy. At a lower dose (2 mg/kg) however, fib-GC-AuNPs and GC-AuNPs could mark approximately half and a quarter of thrombus area, respectively, as compared to the best thrombus marking result. Graphs show mean ± SEM. *P < 0.05 vs. GC-AuNP (both 2 mg/kg and 20 mg/kg) and fib-GC-AuNP (20 mg/kg) groups (ANOVA with post-hoc Mann-Whitney tests). Concentrations of nanoparticles are reported as 'mg Au / kg of animal'. Scale bars = 1 mm.
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Figure 2: Targeted fib-GC-AuNPs are superior to non-targeted GC-AuNPs in mCT imaging of in situ carotid thrombus. A-D, Representative mCT imaging of in situ carotid thrombosis. Thrombi were formed in C57Bl/6 mice by applying stripes of filter paper (1 × 1 mm2) soaked in 10% FeCl3 to the left distal carotid artery (photographs, upper row). Thirty minutes later, mCT thrombus images (upper row, coronal view; lower row, sagittal view) were acquired 5 minutes after intravenous injection of 200 μL GC-AuNPs (A and B) or fib-GC-AuNPs (C and D) of either a low (2 mg/kg; A-C) or high (20 mg/kg; B and D) concentration. At the low administered doses, fib-GC-AuNPs (D) outperforms GC-AuNPs (C), by more clearly marking the carotid thrombus. The “larger” thrombus in (C) vs. (A) reflects better clot visualization due to more avid binding of the targeted compound. At high administered doses, the areas of thrombus-related hyperdense lesions look similar between the animals injected with either GC-AuNPs (B) or fib-GC-AuNPs (D). E, Grouped quantification data. The above mCT imaging findings from the representative animals are corroborated by the quantification data for all 12 animals (n = 3 / group). At a higher dose (20 mg/kg), both fib-GC-AuNPs and non-targeted GC-AuNPs detected carotid thrombus with equal efficacy. At a lower dose (2 mg/kg) however, fib-GC-AuNPs and GC-AuNPs could mark approximately half and a quarter of thrombus area, respectively, as compared to the best thrombus marking result. Graphs show mean ± SEM. *P < 0.05 vs. GC-AuNP (both 2 mg/kg and 20 mg/kg) and fib-GC-AuNP (20 mg/kg) groups (ANOVA with post-hoc Mann-Whitney tests). Concentrations of nanoparticles are reported as 'mg Au / kg of animal'. Scale bars = 1 mm.

Mentions: Carotid thrombi were induced using FeCl3 pledgets on the exposed vessel for 5 minutes, followed by intravenous injection of 200 μL GC-AuNPs or fib-GC-AuNPs, both of which contained either 2.5 mg/mL or 0.25 mg/mL Au. Imaging was done 5 minutes after injection. All six animals in both groups showed similarly strong mCT attenuation localized to the site of carotid thrombosis (Figure 2). At a lower dose (2 mg/kg, 200 μL injected volume; n = 3 / group) however, the same thrombotic insult resulted in much less thrombus visualization. The areas were measured to be relatively low in both groups, particularly in the non-targeted GC-AuNP-injected mice. In one of the three low-dose GC-AuNP group animals, carotid thrombus could not be identified at all. The low dose targeted agent had equivalent performance to the high dose (20 mg/kg, 200 μL injected volume) non-targeted agent. For each given dose level, targeted agent outperformed non-targeted agent, and for each agent, higher dose outperformed lower dose.


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-AuNPs are superior to non-targeted GC-AuNPs in mCT imaging of in situ carotid thrombus. A-D, Representative mCT imaging of in situ carotid thrombosis. Thrombi were formed in C57Bl/6 mice by applying stripes of filter paper (1 × 1 mm2) soaked in 10% FeCl3 to the left distal carotid artery (photographs, upper row). Thirty minutes later, mCT thrombus images (upper row, coronal view; lower row, sagittal view) were acquired 5 minutes after intravenous injection of 200 μL GC-AuNPs (A and B) or fib-GC-AuNPs (C and D) of either a low (2 mg/kg; A-C) or high (20 mg/kg; B and D) concentration. At the low administered doses, fib-GC-AuNPs (D) outperforms GC-AuNPs (C), by more clearly marking the carotid thrombus. The “larger” thrombus in (C) vs. (A) reflects better clot visualization due to more avid binding of the targeted compound. At high administered doses, the areas of thrombus-related hyperdense lesions look similar between the animals injected with either GC-AuNPs (B) or fib-GC-AuNPs (D). E, Grouped quantification data. The above mCT imaging findings from the representative animals are corroborated by the quantification data for all 12 animals (n = 3 / group). At a higher dose (20 mg/kg), both fib-GC-AuNPs and non-targeted GC-AuNPs detected carotid thrombus with equal efficacy. At a lower dose (2 mg/kg) however, fib-GC-AuNPs and GC-AuNPs could mark approximately half and a quarter of thrombus area, respectively, as compared to the best thrombus marking result. Graphs show mean ± SEM. *P < 0.05 vs. GC-AuNP (both 2 mg/kg and 20 mg/kg) and fib-GC-AuNP (20 mg/kg) groups (ANOVA with post-hoc Mann-Whitney tests). Concentrations of nanoparticles are reported as 'mg Au / kg of animal'. Scale bars = 1 mm.
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Related In: Results  -  Collection

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Figure 2: Targeted fib-GC-AuNPs are superior to non-targeted GC-AuNPs in mCT imaging of in situ carotid thrombus. A-D, Representative mCT imaging of in situ carotid thrombosis. Thrombi were formed in C57Bl/6 mice by applying stripes of filter paper (1 × 1 mm2) soaked in 10% FeCl3 to the left distal carotid artery (photographs, upper row). Thirty minutes later, mCT thrombus images (upper row, coronal view; lower row, sagittal view) were acquired 5 minutes after intravenous injection of 200 μL GC-AuNPs (A and B) or fib-GC-AuNPs (C and D) of either a low (2 mg/kg; A-C) or high (20 mg/kg; B and D) concentration. At the low administered doses, fib-GC-AuNPs (D) outperforms GC-AuNPs (C), by more clearly marking the carotid thrombus. The “larger” thrombus in (C) vs. (A) reflects better clot visualization due to more avid binding of the targeted compound. At high administered doses, the areas of thrombus-related hyperdense lesions look similar between the animals injected with either GC-AuNPs (B) or fib-GC-AuNPs (D). E, Grouped quantification data. The above mCT imaging findings from the representative animals are corroborated by the quantification data for all 12 animals (n = 3 / group). At a higher dose (20 mg/kg), both fib-GC-AuNPs and non-targeted GC-AuNPs detected carotid thrombus with equal efficacy. At a lower dose (2 mg/kg) however, fib-GC-AuNPs and GC-AuNPs could mark approximately half and a quarter of thrombus area, respectively, as compared to the best thrombus marking result. Graphs show mean ± SEM. *P < 0.05 vs. GC-AuNP (both 2 mg/kg and 20 mg/kg) and fib-GC-AuNP (20 mg/kg) groups (ANOVA with post-hoc Mann-Whitney tests). Concentrations of nanoparticles are reported as 'mg Au / kg of animal'. Scale bars = 1 mm.
Mentions: Carotid thrombi were induced using FeCl3 pledgets on the exposed vessel for 5 minutes, followed by intravenous injection of 200 μL GC-AuNPs or fib-GC-AuNPs, both of which contained either 2.5 mg/mL or 0.25 mg/mL Au. Imaging was done 5 minutes after injection. All six animals in both groups showed similarly strong mCT attenuation localized to the site of carotid thrombosis (Figure 2). At a lower dose (2 mg/kg, 200 μL injected volume; n = 3 / group) however, the same thrombotic insult resulted in much less thrombus visualization. The areas were measured to be relatively low in both groups, particularly in the non-targeted GC-AuNP-injected mice. In one of the three low-dose GC-AuNP group animals, carotid thrombus could not be identified at all. The low dose targeted agent had equivalent performance to the high dose (20 mg/kg, 200 μL injected volume) non-targeted agent. For each given dose level, targeted agent outperformed non-targeted agent, and for each agent, higher dose outperformed lower dose.

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