Establishment of a Modified and Standardized Ferric Chloride-Induced Rat Carotid Artery Thrombosis Model

Progress in the field of animal models of antiphospholipid syndrome

Antiphospholipid syndrome (APS) is an autoimmune disease characterized by recurrent arteriovenous thrombosis and pathological pregnancy, accompanied by persistent antiphospholipid antibodies, (aPL). The incidence of APS is increasing year by year, clinicians lack of understanding of this type of disease, easy to misdiagnose and miss the diagnosis. Therefore, it is extremely important to establish a suitable animal model to reduce the process of disease development as much as possible and improve clinicians' understanding and understanding. This review will summarize the animal models of APS from the aspects of modeling methods, modeling mechanism, evaluation indicators and advantages and disadvantages of methods, providing a reference for finding an animal model highly similar to human APS, helping researchers to further clarify the pathogenesis of APS and find potential therapeutic targets, so as to achieve early diagnosis, early intervention, and ultimately improve the prognosis of patients.

rtPA-loaded fucoidan polymer microbubbles for the targeted treatment of stroke

Systemic injection of thrombolytic drugs is the gold standard treatment for non-invasive blood clot resolution. The most serious risks associated with the intravenous injection of tissue plasminogen activator-like proteins are the bleeding complication and the dose related neurotoxicity. Indeed, the drug has to be injected in high concentrations due to its short half-life, the presence of its natural blood inhibitor (PAI-1) and the fast hepatic clearance (0.9 mg/kg in humans, 10 mg/kg in mouse models). Overall, there is a serious need for a dose-reduced targeted treatment to overcome these issues. We present in this article a new acoustic cavitation-based method for polymer MBs synthesis, three times faster than current hydrodynamic-cavitation method. The generated MBs are ultrasound responsive, stable and biocompatible. Their functionalization enabled the efficient and targeted treatment of stroke, without side effects. The stabilizing shell of the MBs is composed of Poly-Isobutyl Cyanoacrylate (PIBCA), copolymerized with fucoidan. Widely studied for its targeting properties, fucoidan exhibit a nanomolar affinity for activated endothelium and activated platelets (P-selectins). Secondly, the thrombolytic agent (rtPA) was loaded onto microbubbles (MBs) with a simple adsorption protocol. Hence, the present study validated the in vivo efficiency of rtPA-loaded Fuco MBs to be over 50 % more efficient than regular free rtPA injection for stroke resolution. In addition, the relative injected rtPA grafted onto targeting MBs was 1/10th of the standard effective dose (1 mg/kg in mouse). As a result, no hemorrhagic event, BBB leakage nor unexpected tissue distribution were observed.

Biomimetic Platelet Nanomotors for Site-Specific Thrombolysis and Ischemic Injury Alleviation

Due to the mortality associated with thrombosis and its high recurrence rate, there is a need to investigate antithrombotic approaches. Noninvasive site-specific thrombolysis is a current approach being used; however, its usage is characterized by the following limitations: low targeting efficiency, poor ability to penetrate clots, rapid half-life, lack of vascular restoration mechanisms, and risk of thrombus recurrence that is comparable to that of traditional pharmacological thrombolysis agents. Therefore, it is vital to develop an alternative technique that can overcome the aforementioned limitations. To this end, a cotton-ball-shaped platelet (PLT)-mimetic self-assembly framework engineered with a phototherapeutic poly(3,4-ethylenedioxythiophene) (PEDOT) platform has been developed. This platform is capable of delivering a synthetic peptide derived from hirudin P6 (P6) to thrombus lesions, forming P6@PEDOT@PLT nanomotors for noninvasive site-specific thrombolysis, effective anticoagulation, and vascular restoration. Regulated by P-selectin mediation, the P6@PEDOT@PLT nanomotors target the thrombus site and subsequently rupture under near-infrared (NIR) irradiation, achieving desirable sequential drug delivery. Furthermore, the movement ability of the P6@PEDOT@PLT nanomotors under NIR irradiation enables effective penetration deep into thrombus lesions, enhancing bioavailability. Biodistribution analyses have shown that the administered P6@PEDOT@PLT nanomotors exhibit extended circulation time and metabolic capabilities. In addition, the photothermal therapy/photoelectric therapy combination can significantly augment the effectiveness (ca. 72%) of thrombolysis. Consequently, the precisely delivered drug and the resultant phototherapeutic-driven heat-shock protein, immunomodulatory, anti-inflammatory, and inhibitory plasminogen activator inhibitor-1 (PAI-1) activities can restore vessels and effectively prevent rethrombosis. The described biomimetic P6@PEDOT@PLT nanomotors represent a promising option for improving the efficacy of antithrombotic therapy in thrombus-related illnesses.

A Reliable Nonhuman Primate Model of Ischemic Stroke with Reproducible Infarct Size and Long-term Sensorimotor Deficits

A nonhuman primate model of ischemic stroke is considered as an ideal preclinical model to replicate various aspects of human stroke because of their similarity to humans in genetics, neuroanatomy, physiology, and immunology. However, it remains challenging to produce a reliable and reproducible stroke model in nonhuman primates due to high mortality and variable outcomes. Here, we developed a focal cerebral ischemic model induced by topical application of 50% ferric chloride (FeCl₃) onto the MCA-M1 segment through a cranial window in the cynomolgus monkeys. We found that FeCl₃ rapidly produced a stable intraarterial thrombus that caused complete occlusion of the MCA, leading to the quick decrease of the regional cerebral blood flow in 10 min. A typical cortical infarct was detected 24 hours by magnetic resonance imaging (MRI) and was stable at least for 1 month after surgery. The sensorimotor deficit assessed by nonhuman primate stroke scale was observed at 1 day and up to 3 months after ischemic stroke. No spontaneous revascularization or autolysis of thrombus was observed, and vital signs were not affected. All operated cynomolgus monkeys survived. Our data suggested that FeCl₃-induced stroke in nonhuman primates was a replicable and reliable model that is necessary for the correct prediction of the relevance of experimental therapeutic approaches in human beings.

Nonhuman Primate Models of Ischemic Stroke and Neurological Evaluation After Stroke

Nonhuman primates are closer to human beings than rodents in genetics, neuroanatomy, physiology and immunology. Nonhuman primates are therefore considered an ideal preclinical model to replicate various aspects of human stroke. Ischemia stroke models in nonhuman primates can better fit the physiological symptoms and changes in humans after cerebral ischemia. Currently, various construction methods and neurological evaluation methods have been developed and applied to stroke models of nonhuman primates, including craniectomy models, endovascular stroke models, autologous thrombus models and intraluminal filament models. Meanwhile, new innovative methods have emerged, such as the endothelin-1 model and photothrombosis model. In the past thirty years, these model studies have explored various mechanisms that are initiated in the first minutes, hours, and days after a stroke. Permanent and temporary middle cerebral artery occlusion models have been trying to simulate the complex situation of human stroke. However, a comprehensive comparison of the above methods, including their advantages and disadvantages, difficulty and application fields, is limited. Here, we introduce various modeling methods that are currently available for nonhuman primate stroke models, compare the differences between these different preparation methods, and analyze the advantages and disadvantages of the various methods and the fields of application. The imaging detection methods of nonhuman primates after cerebral ischemia and the neurological evaluation methods after stroke are also discussed briefly. Methods are sorted and compared so that scholars can choose appropriate modeling methods and evaluation methods to establish nonhuman primate stroke models.