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Thrombosis of Apoe −/-carotid artery triggered by injury with ultrasound or with a suture needle. (a) Time-course of thrombosis in response to ultrasound injury or needle injury of carotid artery of an Apoe −/-mouse. (b) Transversal cryosection of the carotid artery at the site of injury with immunostaining for platelets (GPIbβ brown staining) with hematoxylin counterstaining only in the case of needle injury.
Source publication
In spite of current treatment strategies, myocardial infarction and stroke are still major causes of death worldwide. These events are triggered by damage of an atherosclerotic plaque, resulting in occlusive thrombus formation. Mouse studies have significantly contributed to our understanding of the mechanisms of atherogenesis and of thrombosis fol...
Contexts in source publication
Context 1
... the model of ultrasound-induced plaque injury, the tip of an ultrasound probe is pressed against the carotid plaque shoulder and ultrasound is applied for 10 s, as established by two research groups (Table I) [18,19]. In both cases, the application of ultrasound results in loss of the endothelial cell layer and presence of adherent platelets in contact with plaque material (Figure 2b), collagen exposure, and luminal formation of a platelet-rich thrombus, accompanied by intra-plaque intrusion of erythrocytes and fibrin formation. Formed thrombi are non-occlusive and display a biphasic kinetic, with a maximum in thrombus size reached after 30-60 s, after which the thrombus size progressively declines within 10-15 min. ...
Context 2
... duration of the scratching varies according to the model, with the needle being moved forward and backward only twice [25] or the scratching being performed for 3 to 4 min until rupture of the plaque is observed under the optical microscope [19]. Scratching leads to the formation of either a small thrombus on the surface of the plaque [25] or a larger fibrin-rich thrombus in contact with collagen-rich plaque material, which reaches maximum size just after the needle is removed and gradually decreases over the next 15 min (Figure 2a) [19]. In both cases, plaque damage is more pronounced than upon ultrasound application, with rupture of the atherosclerotic plaque and exposure of the plaque material to the blood (Figure 2a,b) [19,25], leading to the formation of a thrombus that is larger in size [19]. ...
Context 3
... leads to the formation of either a small thrombus on the surface of the plaque [25] or a larger fibrin-rich thrombus in contact with collagen-rich plaque material, which reaches maximum size just after the needle is removed and gradually decreases over the next 15 min (Figure 2a) [19]. In both cases, plaque damage is more pronounced than upon ultrasound application, with rupture of the atherosclerotic plaque and exposure of the plaque material to the blood (Figure 2a,b) [19,25], leading to the formation of a thrombus that is larger in size [19]. ...
Citations
... This significantly limits the ability of these models to be used in pre-clinical testing of anti-thrombotic drugs and are instead principally used for basic understanding of how plaques form, develop, and rupture. Those animal models that do demonstrate plaque rupture are unpredictable-with the most effective mouse models demonstrating a 50-75% rupture rate, occurring irregularly over prolonged study periods that last many months [8,9]. This makes studies time-consuming, costly, and reliant on the tracking of severe symptoms of plaque rupture that cause significant suffering to the animal. ...
... This makes studies time-consuming, costly, and reliant on the tracking of severe symptoms of plaque rupture that cause significant suffering to the animal. An alternative approach has been to use intravital microscopy in ApoE -/mice to monitor thrombotic response after the plaque was artificially disrupted using ultrasound, FeCl 3 , photochemical injury, ligation, or needle injury [9]. However, previous work has demonstrated that various responses are observed depending on the method of injury used in these atherothrombosis models [9,10]; therefore, it is uncertain whether these results are representative of the clotting responses experienced in patients. ...
... A total of 10 µM copper sulphate was added to the LDL solution and incubated for 24 h at 37 • C to allow for its oxidation. Excess copper sulphate was then removed from the sample solution through dialyzing the sample against a PBS buffer containing 100 µM Biomimetics 2024, 9,372 4 of 24 EDTA for 24 h at room temperature under sterile conditions. Dialysis was performed using a Slide-a-Lyzer dialysis cassette (gamma-irradiated 10K MWCO; Fisher Scientific) according to the manufacturer's instructions. ...
Acute cardiovascular events result from clots caused by the rupture and erosion of atherosclerotic plaques. This paper aimed to produce a functional biomimetic hydrogel of the neointimal layer of the atherosclerotic plaque that can support thrombogenesis upon exposure to human blood. A biomimetic hydrogel of the neointima was produced by culturing THP-1-derived foam cells within 3D collagen hydrogels in the presence or absence of atorvastatin. Prothrombin time and platelet aggregation onset were measured after exposure of the neointimal models to platelet-poor plasma and washed platelet suspensions prepared from blood of healthy, medication-free volunteers. Activity of the extrinsic coagulation pathway was measured using the fluorogenic substrate SN-17. Foam cell formation was observed following preincubation of the neointimal biomimetic hydrogels with oxidized LDL, and this was inhibited by pretreatment with atorvastatin. The neointimal biomimetic hydrogel was able to trigger platelet aggregation and blood coagulation upon exposure to human blood products. Atorvastatin pretreatment of the neointimal biomimetic layer significantly reduced its pro-aggregatory and pro-coagulant properties. In the future, this 3D neointimal biomimetic hydrogel can be incorporated as an additional layer within our current thrombus-on-a-chip model to permit the study of atherosclerosis development and the screening of anti-thrombotic drugs as an alternative to current animal models.
... The most widely used models are ApoE or Ldlr knockout mice [98]. These animals only develop plaques until the calcific fibroatheroma stage (stage Vc), but never exhibit plaque rupture unless induced e.g., by injury [99]. This limitation together with ethical concerns and unresolved inter-species differences point out the relevance of developing in vitro models of arterial thrombosis using human-derived biological materials. ...
... However, animal models do not fully replicate human physiology or human disease. 17 There are always differences between animal models with human physiology, and conducting operations are time-consuming and laborious. ...
Plain Language Summary
What is the context? To study the mechanism of arterial thrombosis, including the platelet adhesion and aggregation behavior and the coagulation process.
Microfluidic technology is commonly used to study thrombosis. Microfluidic technology can simulate the real physiological environment on the microscopic scale in vitro, with high throughput, low cost, and fast speed.
As an innovative experimental platform, microfluidic technology has made remarkable progress and has found applications in the fields of biology and medicine.
What is new? This review summarizes the different fabrication methods of microfluidics and compares the advantages and disadvantages of these methods. Recent developments in microfluidic integrated systems and modular microfluidic systems have led to more diversified and automated microfluidic chips in the future.
The different types and functions of microfluidic models are summarized. Platelet adhesion aggregation and coagulation processes, as well as arterial thrombus-related shear force changes and mechanical behaviors, were investigated by constructing artificial blood vessels and reproducing hemodynamics.
Microfluidics can provide a basis for the development of personalized thrombosis treatment strategies. By analyzing the mechanism of action of existing drugs, using microfluidic technology for high-throughput screening of drugs and evaluating drug efficacy, more drug therapy possibilities can be developed.
What is the impact?
This review utilizes microfluidics to further advance the study of arterial thrombosis, and microfluidics is also expected to play a greater role in the biomedical field in the future.
... The resulting deposits are highly thrombogenic due to their potential to obstruct blood flow and exert high shear stresses on the vessel wall (Libby et al., 2019). This is one of many causative factors that can cause an atherosclerotic vessel wall to sustain an injury and trigger the development of a thrombus (Karel et al., 2020;Mercer and Guzik, 2019). Atherosclerosis of the carotid artery is one of the major causes of ischemic stroke, with artery-to-artery embolism being the central stroke mechanism in patients with atherosclerosis of the carotid artery (Woo et al., 2020). ...
Stroke, a neurological disease, is one of the leading causes of death worldwide, resulting in long-term disability in most survivors. Annual stroke costs in the United States alone were estimated at $46 billion recently. Stroke pathophysiology is complex, involving multiple causal factors, among which atherosclerosis, thrombus, and embolus are prevalent. The molecular mechanisms involved in the pathophysiology are essential to understanding targeted drug development. Some common mechanisms are excitotoxicity and calcium overload, oxidative stress, and neuroinflammation. In addition, various modifiable and non-modifiable risk factors increase the chances of stroke manifolds. Once a patient encounters a stroke, complete restoration of motor ability and cognitive skills is often rare. Therefore, shaping therapeutic strategies is paramount for finding a viable therapeutic agent. Apart from tPA, an FDA-approved therapy that is applied in most stroke cases, many other therapeutic strategies have been met with limited success. Stroke therapies often involve a combination of multiple strategies to restore the patient's normal function. Certain drugs like Gamma-aminobutyric receptor agonists (GABA), Glutamate Receptor inhibitors, Sodium, and Calcium channel blockers, and fibrinogen-depleting agents have shown promise in stroke treatment. Recently, a drug, DM199, a recombinant (synthetic) form of a naturally occurring protein called human tissue kallikrein-1 (KLK1), has shown great potential in treating stroke with fewer side effects. Furthermore, DM199 has been found to overcome the limitations presented when using tPA and/or mechanical thrombectomy. Cell-based therapies like Neural Stem Cells, Hematopoietic stem cells (HSCs), and Human umbilical cord blood-derived mesenchymal stem cells (HUCB-MSCs) are also being explored as a treatment of choice for stroke. These therapeutic agents come with merits and demerits, but continuous research and efforts are being made to develop the best therapeutic strategies to minimize the damage post-stroke and restore complete neurological function in stroke patients.
... Opposed to the aforementioned processes of atherosclerosis development, the role of platelets in subsequent thrombus formation is wellstudied and established [102][103][104]. Traditionally, a plaque was described as either being stable or vulnerable, where the latter is more prone to rupture. ...
... As discussed in more detail in our previous work, interactions of platelets with activated endothelium are distinct from the aforementioned thrombotic processes [12]. Interestingly, in vivo evidence of the role of platelets in atherothrombosis is either predominantly based on models of plaque rupture or no clear distinction is made between rupture, erosion and healing [103,104]. ...
Atherosclerosis is an underlying cause of a broad array of cardiovascular diseases characterized by plaques, arterial wall thickening initiated by hyperlipidemia, pro-inflammatory signals, endothelial dysfunction and the influx of inflammatory cells. By still incompletely characterized mechanisms, these plaques can destabilize or erode, leading to thrombosis and blood vessel occlusion and becomes clinically manifest as angina pectoris, myocardial infarction (MI) or stroke.
Among the several blood cell types that are involved in the development of atherosclerosis, the role of platelets during the thrombotic occlusion of ruptured or eroded plaques is well established and clinically exploited as evident by the extensive use of platelet inhibitors. However, there is increasing evidence that platelets are also involved in the earlier stages of atheroma development by exhibiting pro-inflammatory activities. The scope of this review is to describe the role of platelets in the initiation and propagation stages of atherosclerosis and beyond; in atherothrombotic complications.
OBJECTIVE
To innovatively developed a macrophage-target nanoparticle based contrast-enhanced high-resolution magnetic resonance vessel wall imaging (HR-VWI) strategy to characterize the plaques’ vulnerable features on rabbits.
BACKGROUND
Lacking of sensitive and specific image-marker of HR-VWI leads this technique depending upon the plaque morphological characteristics. Nanoparticle-based contrast agents modified with targeting ligands allow amplifying MR signals of the interested components. The key to successful translation is the requirement that conducting studies in larger animals to provide reasonable diagnostic readouts.
METHODS
The HR-VWI enhanced with macrophage-targeted PP1-Au@GSH@Gd (GdMG) nanoclusters (NCs) and the conventional Gadovist were utilized for the plaque vulnerability evaluation by a systematic histogram analysis in atherosclerosis (AS) rabbit model.
RESULTS
Due to the compelling targeting capacity of GdMG NCs to foamy macrophages, the contrast-to-noise ratio (CNR) from pre-injection baseline dramatically raised from 6.50 to 36.91 ( p < 0.001), with an increment of 1.39-fold higher than that of the Gadovist approach. Spearman’ s correlation test confirmed that the coefficient of variation (CV) derived from the histogram analysis based on GdMG NCs HR-VWI was indeed positively linearly correlated with pathology vulnerability index (VI P ) significantly ( p < 0.05) with adjusted R ² = 0.775. Finally, mathematic formulas with histogram-derived parameters as variables were fitted to quantitatively calculate the histogram vulnerability index (VI H ) with the strength of the adjusted R ² = 0.952 ( p < 0.001), and Area under the curve (AUC) of 0.875 ( p < 0.001) to realize the in vivo and quantitative calculation of the plaque vulnerability.
CONCLUSION
Profiting from the splendid inflammation targeted capacity and excellent MRI performance of GdMG NCs, as well as the highly quantitative characteristics of histogram analysis, we disclosed that our established imaging protocol was able to identify the plaques’ vulnerability index that were comparable to pathological examinations in both retrospective and prospective experiments.
Near-infrared (NIR)-light-modulated photothermal thrombolysis has been investigated to overcome the hemorrhage danger posed by clinical clot-busting substances. A long-standing issue in thrombosis fibrinolytics is the lack of lesion-specific therapy, which should not be ignored. Herein, a novel thrombolysis therapy using photothermal disintegration of a fibrin clot was explored through dual-targeting glycol chitosan/heparin-decorated polypyrrole nanoparticles (GCS-PPY-H NPs) to enhance thrombus delivery and thrombolytic therapeutic efficacy. GCS-PPY-H NPs can target acidic/P-selectin high-expression inflammatory endothelial cells/thrombus sites for initiating lesion-site-specific thrombolysis by hyperthermia using NIR irradiation. A significant fibrin clot-clearance rate was achieved with thrombolysis using dual-targeting/modality photothermal clot disintegration in vivo. The molecular level mechanisms of the developed nanoformulations and interface properties were determined using multiple surface specific analytical techniques, such as particle size distribution, zeta potential, electron microscopy, Fourier-transform infrared spectroscopy (FTIR), wavelength absorbance, photothermal, immunofluorescence, and histology. Owing to the augmented thrombus delivery of GCS-PPY-H NPs and swift treatment time, dual-targeting photothermal clot disintegration as a systematic treatment using GCS-PPY-H NPs can be effectively applied in thrombolysis. This novel approach possesses a promising future for thrombolytic treatment.
