Efficacy and safety of sonothrombolysis in patients with acute ischemic stroke: A systematic review and meta-analysis

Ultrasound-mediated cardiovascular thrombolysis: from Sonothrombolysis to Sonoperfusion

The incidence of coronary artery disease has been increasing in recent years, with acute myocardial infarction as its most severe onset. The major aim for clinical treatment is to restore myocardial blood supply with the recanalization of coronary circulation as early as possible, while the still existed issue of microcirculation thromboembolism has become a serious obstacle. Thus, thrombus elimination in coronary microcirculation is crucial and essential to improve the treatment outcome of acute myocardial infarction. In recent years, from sonothrombolysis to sonoperfusion, ultrasound-mediated cardiovascular thrombolysis can effectively solve the problem of vascular thromboembolism, including microcirculation thromboembolism, and the treatment method is expected to obtain satisfied thrombolytic treatment effect with microthrombus elimination in coronary microvessels and function recovery of terminal microcirculation, which has potential clinical value for the establishment of novel treatment for coronary thromboembolism. Therefore, this paper reviews ultrasound-mediated cardiovascular thrombolysis including sonothrombolysis and sonoperfusion for the application exploration in the treatment of coronary artery thromboembolism, the mechanism of action, and its research progress.

Chaperones vs. oxidative stress in the pathobiology of ischemic stroke

As many proteins prioritize functionality over constancy of structure, a proteome is the shortest stave in the Liebig's barrel of cell sustainability. In this regard, both prokaryotes and eukaryotes possess abundant machinery supporting the quality of the proteome in healthy and stressful conditions. This machinery, namely chaperones, assists in folding, refolding, and the utilization of client proteins. The functions of chaperones are especially important for brain cells, which are highly sophisticated in terms of structural and functional organization. Molecular chaperones are known to exert beneficial effects in many brain diseases including one of the most threatening and widespread brain pathologies, ischemic stroke. However, whether and how they exert the antioxidant defense in stroke remains unclear. Herein, we discuss the chaperones shown to fight oxidative stress and the mechanisms of their antioxidant action. In ischemic stroke, during intense production of free radicals, molecular chaperones preserve the proteome by interacting with oxidized proteins, regulating imbalanced mitochondrial function, and directly fighting oxidative stress. For instance, cells recruit Hsp60 and Hsp70 to provide proper folding of newly synthesized proteins-these factors are required for early ischemic response and to refold damaged polypeptides. Additionally, Hsp70 upregulates some dedicated antioxidant pathways such as FOXO3 signaling. Small HSPs decrease oxidative stress via attenuation of mitochondrial function through their involvement in the regulation of Nrf- (Hsp22), Akt and Hippo (Hsp27) signaling pathways as well as mitophagy (Hsp27, Hsp22). A similar function has also been proposed for the Sigma-1 receptor, contributing to the regulation of mitochondrial function. Some chaperones can prevent excessive formation of reactive oxygen species whereas Hsp90 is suggested to be responsible for pro-oxidant effects in ischemic stroke. Finally, heat-resistant obscure proteins (Hero) are able to shield client proteins, thus preventing their possible over oxidation.

A 9-Fr Endovascular Therapy Transducer With an Acoustic Metamaterial Lens for Rapid Stroke Thrombectomy

Large vessel occlusion (LVO) stroke, in which major cerebral arteries such as the internal carotid and middle cerebral arteries supplying the brain are occluded, is the most debilitating form of acute ischemic stroke (AIS). The current gold standard treatment for LVO stroke is mechanical thrombectomy; however, initial attempts to recanalize these large, proximal arteries supplying the brain fail in up to 75% of cases, leading to repeated passes that decrease the likelihood of success and affect patient outcomes. We report the design, fabrication, and testing of a mm forward-treating ultrasound (US) transducer with an acoustic metamaterial lens to dissolve blood clots recalcitrant to first-pass mechanical thrombectomy in LVO stroke. Due to the lens with microscale features, the device was able to produce a increase in peak negative pressure (PNP) (4.3 versus 1.8 MPa) and increase in blood clot dissolution rate ( versus mg/min) with 90% mass reduction after 30 min of treatment. In this small endovascular form factor, the acoustic metamaterial lens increased the acoustic output from the transducer while minimizing the US energy delivered to the surrounding areas outside of the treatment volume.

Effect of continuous 2 MHz transcranial ultrasound as an adjunct to tenecteplase thrombolysis in acute anterior circulation ischemic stroke patients: an open labeled non-randomized clinical trial

The treatment of acute ischemic stroke has improved in last few decades. While meta-analyses of several trials have established the safety and efficacy of Intravenous (IV) Tenecteplase thrombolysis, concomitant continuous transcranial doppler (TCD) ultrasound administration has not been assessed in any clinical trial. The aim of this study was to determine the effects of continuous 2 MHz TCD ultrasound during IV Tenecteplase thrombolysis for Middle cerebral artery (MCA) stroke. A total of 19 patients were included, 13 received TCD ultrasound and 6 sham TCD with IV Tenecteplase. TCD spectrum and difference in Pre and post TCD parameters were measured. Asymptomatic hemorrhagic transformation of infarct was seen in two patients. There was no mortality or clinical worsening in the sonothrombolysis group as against sham sonothrombolysis group. Median of peak systolic velocity was increased in both the sonothrombolysis (P = 0.0002) and sham sonothrombolysis group (P-value = 0.001). The difference in change in mean flow velocity between two groups, sonothrombolysis (11 cm/sec) and sham sonothrombolysis (3.5 cm/sec) were also significantly different (P = 0.014). This pilot work has established safety of continuous 30 min TCD application along with IV Tenecteplase thrombolysis and it concludes that concomitant 2 MHz TCD ultrasound administration significantly increased the MCA blood flow compared to chemothrombolysis alone.CTRI Registered Number: CTRI/2021/02/031418.

Ultrasound combined with urokinase under key-shaped bone window enhances blood clot lysis in an in vitro model of spontaneous intracerebral hemorrhage

OBJECTIVE

Minimally invasive surgery for spontaneous intracerebral hemorrhage is impeded by inadequate lysis of the target blood clot. Ultrasound is thought to expedite intravascular thrombolysis, thereby facilitating vascular recanalization. However, the impact of ultrasound on intracerebral blood clot lysis remains uncertain. This study aimed to explore the feasibility of combining ultrasound with urokinase to enhance blood clot lysis in an in vitro model of spontaneous intracerebral hemorrhage.

METHODS

The blood clots were divided into four groups: control group, ultrasound group, urokinase group, and ultrasound + urokinase group. Using our experimental setup, which included a key-shaped bone window, we simulated a minimally invasive puncture and drainage procedure for spontaneous intracerebral hemorrhage. The blood clot was then irradiated using ultrasound. Blood clot lysis was assessed by weighing the blood clot before and after the experiment. Potential adverse effects were evaluated by measuring the temperature variation around the blood clot in the ultrasound + urokinase group.

RESULTS

A total of 40 blood clots were observed, with 10 in each experimental group. The blood clot lysis rate in the ultrasound group, urokinase group, and ultrasound + urokinase group (24.83 ± 4.67%, 47.85 ± 7.09%, 61.13 ± 4.06%) was significantly higher than that in the control group (16.11 ± 3.42%) (p = 0.02, p < 0.001, p < 0.001). The blood clot lysis rate in the ultrasound + urokinase group (61.13 ± 4.06%) was significantly higher than that in the ultrasound group (24.83 ± 4.67%) (p < 0.001) or urokinase group (47.85 ± 7.09%) (p < 0.001). In the ultrasound + urokinase group, the mean increase in temperature around the blood clot was 0.26 ± 0.15°C, with a maximum increase of 0.38 ± 0.09°C. There was no significant difference in the increase in temperature regarding the main effect of time interval (F = 0.705, p = 0.620), the main effect of distance (F = 0.788, p = 0.563), or the multiplication interaction between time interval and distance (F = 1.100, p = 0.342).

CONCLUSIONS

Our study provides evidence supporting the enhancement of blood clot lysis in an in vitro model of spontaneous intracerebral hemorrhage through the combined use of ultrasound and urokinase. Further animal experiments are necessary to validate the experimental methods and results.

Overcoming biological barriers to improve treatment of a Staphylococcus aureus wound infection

Chronic wounds frequently become infected with bacterial biofilms which respond poorly to antibiotic therapy. Aminoglycoside antibiotics are ineffective at treating deep-seated wound infections due to poor drug penetration, poor drug uptake into persister cells, and widespread antibiotic resistance. In this study, we combat the two major barriers to successful aminoglycoside treatment against a biofilm-infected wound: limited antibiotic uptake and limited biofilm penetration. To combat the limited antibiotic uptake, we employ palmitoleic acid, a host-produced monounsaturated fatty acid that perturbs the membrane of gram-positive pathogens and induces gentamicin uptake. This novel drug combination overcomes gentamicin tolerance and resistance in multiple gram-positive wound pathogens. To combat biofilm penetration, we examined the ability of sonobactericide, a non-invasive ultrasound-mediated-drug delivery technology to improve antibiotic efficacy using an in vivo biofilm model. This dual approach dramatically improved antibiotic efficacy against a methicillin-resistant Staphylococcus aureus (MRSA) wound infection in diabetic mice.

Microbubbles for human diagnosis and therapy

Microbubbles (MBs) were observed for the first time in vivo as a curious consequence of quick saline injection during ultrasound (US) imaging of the aortic root, more than 50 years ago. From this serendipitous event, MBs are now widely used as contrast enhancers for US imaging. Their intrinsic properties described in this review, allow a multitude of designs, from shell to gas composition but also from grafting targeting agents to drug payload encapsulation. Indeed, the versatile MBs are deeply studied for their dual potential in imaging and therapy. As presented in this paper, new generations of MBs now opens perspectives for targeted molecular imaging along with the development of new US imaging systems. This review also presents an overview of the different therapeutic strategies with US and MBs for cancer, cardiovascular diseases, and inflammation. The overall aim is to overlap those fields in order to find similarities in the MBs application for treatment enhancement associated with US. To conclude, this review explores the new scales of MBs technologies with nanobubbles development, and along concurrent advances in the US imaging field. This review ends by discussing perspectives for the booming future uses of MBs.

A Model of High-Speed Endovascular Sonothrombolysis with Vortex Ultrasound-Induced Shear Stress to Treat Cerebral Venous Sinus Thrombosis

This research aims to demonstrate a novel vortex ultrasound enabled endovascular thrombolysis method designed for treating cerebral venous sinus thrombosis (CVST). This is a topic of substantial importance since current treatment modalities for CVST still fail in as many as 20% to 40% of the cases, and the incidence of CVST has increased since the outbreak of the coronavirus disease 2019 pandemic. Compared with conventional anticoagulant or thrombolytic drugs, sonothrombolysis has the potential to remarkably shorten the required treatment time owing to the direct clot targeting with acoustic waves. However, previously reported strategies for sonothrombolysis have not demonstrated clinically meaningful outcomes (e.g., recanalization within 30 min) in treating large, completely occluded veins or arteries. Here, we demonstrated a new vortex ultrasound technique for endovascular sonothrombolysis utilizing wave-matter interaction-induced shear stress to enhance the lytic rate substantially. Our in vitro experiment showed that the lytic rate was increased by at least 64.3% compared with the nonvortex endovascular ultrasound treatment. A 3.1-g, 7.5-cm-long, completely occluded in vitro 3-dimensional model of acute CVST was fully recanalized within 8 min with a record-high lytic rate of 237.5 mg/min for acute bovine clot in vitro. Furthermore, we confirmed that the vortex ultrasound causes no vessel wall damage over ex vivo canine veins. This vortex ultrasound thrombolysis technique potentially presents a new life-saving tool for severe CVST cases that cannot be efficaciously treated using existing therapies.

A 3D finite element model to study the cavitation induced stresses on blood-vessel wall during the ultrasound-only phase of photo-mediated ultrasound therapy

Photo-mediated ultrasound therapy (PUT) is a novel technique utilizing synchronized ultrasound and laser to generate enhanced cavitation inside blood vessels. The enhanced cavitation inside blood vessels induces bio-effects, which can result in the removal of micro-vessels and the reduction in local blood perfusion. These bio-effects have the potential to treat neovascularization diseases in the eye, such as age-related macular degeneration and diabetic retinopathy. Currently, PUT is in the preclinical stage, and various PUT studies on in vivo rabbit eye models have shown successful removal of micro-vessels. PUT is completely non-invasive and particle-free as opposed to current clinical treatments such as anti-vascular endothelial growth factor therapy and photodynamic therapy, and it precisely removes micro-vessels without damaging the surrounding tissue, unlike laser photocoagulation therapy. The stresses produced by oscillating bubbles during PUT are responsible for the induced bio-effects in blood vessels. In our previous work, stresses induced during the first phase of PUT due to combined ultrasound and laser irradiation were studied using a 2D model. In this work, stresses induced during the third or last phase of PUT due to ultrasound alone were studied using a 3D finite element method-based numerical model. The results showed that the circumferential and shear stress increased as the bubble moves from the center of the vessel toward the vessel wall with more than a 16 times increase in shear stress from 1.848 to 31.060 kPa as compared to only a 4 times increase in circumferential stress from 211 to 906 kPa for a 2 µm bubble placed inside a 10 µm vessel on the application of 1 MHz ultrasound frequency and 130 kPa amplitude. In addition, the stresses decreased as the bubble was placed in smaller sized vessels with a larger decrease in circumferential stress. The changes in shear stress were found to be more dependent on the bubble-vessel wall distance, and the changes in circumferential stress were more dependent on the bubble oscillation amplitude. Moreover, the bubble shape changed to an ellipsoidal with a higher oscillation amplitude in the vessel's axial direction as it was moved closer to the vessel wall, and the bubble oscillation amplitude decreased drastically as it was placed in vessels of a smaller size.

Meta-Analysis of the Effectiveness and Safety of Intravenous Thrombolysis in Patients with Acute Cerebral Infarction

In this paper, a meta-analysis of the effectiveness and safety of intravenous thrombolysis in patients with acute cerebral infarction was carried out, the original literature inclusion criteria and retrieval strategies were developed, and the collection deadline was about new oral anticoagulants and other methods for the antithrombotic intravenous thrombolytic treatment of patients with acute cerebral infarction for the relevant literature on the safety and effectiveness comparison. First, the quality of the literature is evaluated according to whether the included studies are randomized controlled trials, whether there is randomized concealment, whether blinding is used, and whether they are withdrawn or lost to follow-up, and the RevMan 5.2 software is used for meta-analysis. At the same time, grey literature databases such as dissertations were experimentally searched, and all randomized controlled studies (RCT), nonrandomized controlled studies, case-controlled studies, cohort studies, case series reports, etc. of Wingspan in the treatment of intracranial atherosclerotic stenosis were collected. In the prevention of myocardial infarction in patients with acute cerebral infarction, the difference between the two was not statistically significant (RR = 0.82, 95% CI (0.57, 1.17), P = 0.27). Compared with other methods, it can significantly reduce the all-cause mortality of patients with nonvalvular venous thrombolysis, and the difference is statistically significant (RR = 0.90, 95% CI (0.85, 0.96), P = 0.001). Experimental results show that in terms of safety, the new oral anticoagulant is better than other methods in reducing minor bleeding in patients with acute cerebral infarction, and the difference is statistically significant (RR = 0.87, 95% CI (0.76, 0 99), P = 0.03); the effect is better than other methods in reducing the incidence of serious bleeding events, and the difference is statistically significant (RR = 0.79, 95% CI (0.74, 0.85), P < 0.00001).

The Role of Ultrasound as a Diagnostic and Therapeutic Tool in Experimental Animal Models of Stroke: A Review

Ultrasound is a noninvasive technique that provides real-time imaging with excellent resolution, and several studies demonstrated the potential of ultrasound in acute ischemic stroke monitoring. However, only a few studies were performed using animal models, of which many showed ultrasound to be a safe and effective tool also in therapeutic applications. The full potential of ultrasound application in experimental stroke is yet to be explored to further determine the limitations of this technique and to ensure the accuracy of translational research. This review covers the current status of ultrasound applied to monitoring and treatment in experimental animal models of stroke and examines the safety, limitations, and future perspectives.

Intracranial Bleeding After Reperfusion Therapy in Acute Ischemic Stroke

Intracranial hemorrhage is one of the most feared complications following brain infarct. Ischemic tissues have a natural tendency to bleed. Moreover, the first recanalization trials using intravenous thrombolysis have shown an increase in mild to severe intracranial hemorrhage. Symptomatic intracerebral hemorrhage is strongly associated with poor outcomes and is an important factor in recanalization decisions. Stroke physicians have to weigh the potential benefit of recanalization therapies, first, with different risks of intracranial hemorrhage described in randomized controlled trials, and second with numerous risk markers that have been found to be associated with intracranial hemorrhage in retrospective series. These decisions have become quite complex with different intravenous thrombolytics and mechanical thrombectomy. This review aims to outline some elements of the pathophysiological mechanisms and classifications, describe most of the risk factors identified for each reperfusion therapy, and finally suggest future research directions that could help physicians dealing with these complications.

Novel Treatments for Transient Ischemic Attack and Acute Ischemic Stroke

The treatment of acute ischemic stroke is one of the most rapidly evolving areas in medicine. Like all ischemic vascular emergencies, the priority is reperfusion before irreversible infarction. The central nervous system is sensitive to brief periods of hypoperfusion, making stroke a golden hour diagnosis. Although the phrase "time is brain" is relevant today, emerging treatment strategies use more specific markers for consideration of reperfusion than time alone. Innovations in early stroke detection and individualized patient selection for reperfusion therapies have equipped the emergency medicine clinician with more opportunities to help stroke patients and minimize the impact of this disease.