Early Detection and Reversal of Cell Apoptosis Induced by Focused Ultrasound-Mediated Blood-Brain Barrier Opening

Focused ultrasound-induced cell apoptosis for the treatment of tumours

Cancer is a serious public health problem worldwide. Traditional treatments, such as surgery, radiotherapy, chemotherapy, and immunotherapy, do not always yield satisfactory results; therefore, an efficient treatment for tumours is urgently needed. As a convenient and minimally invasive modality, focused ultrasound (FUS) has been used not only as a diagnostic tool but also as a therapeutic tool in an increasing number of studies. FUS can help treat malignant tumours by inducing apoptosis. This review describes the three apoptotic pathways, apoptotic cell clearance, and how FUS affects these three apoptotic pathways. This review also discusses the role of thermal and cavitation effects on apoptosis, including caspase activity, mitochondrial dysfunction, and Ca2+ elease. Finally, this article reviews various aspects of FUS combination therapy, including sensitization by radiotherapy and chemotherapy, gene expression upregulation, and the introduction of therapeutic gases, to provide new ideas for clinical tumour therapy.

Enhancing glioma-specific drug delivery through self-assembly of macrophage membrane and targeted polymer assisted by low-frequency ultrasound irradiation

The blood-brain Barrier (BBB), combined with immune clearance, contributes to the low efficacy of drug delivery and suboptimal treatment outcomes in glioma. Here, we propose a novel approach that combines the self-assembly of mouse bone marrow-derived macrophage membrane with a targeted positive charge polymer (An-PEI), along with low-frequency ultrasound (LFU) irradiation, to achieve efficient and safe therapy for glioma. Our findings demonstrate the efficacy of a charge-induced self-assembly strategy, resulting in a stable co-delivery nanosystem with a high drug loading efficiency of 44.2 %. Moreover, this structure triggers a significant release of temozolomide in the acidic environment of the tumor microenvironment. Additionally, the macrophage membrane coating expresses Spyproteins, which increase the amount of An-BMP-TMZ that can evade the immune system by 40 %, while LFU irradiation treatment facilitates the opening of the BBB, allowing for enormously increased entry of An-BMP-TMZ (approximately 400 %) into the brain. Furthermore, after crossing the BBB, the Angiopep-2 peptide-modified An-BMP-TMZ exhibits the ability to selectively target glioma cells. These advantages result in an obvious tumor inhibition effect in animal experiments and significantly improve the survival of glioma-bearing mice. These results suggest that combining the macrophage membrane-coated drug delivery system with LFU irradiation offers a feasible approach for the accurate, efficient and safe treatment of brain disease.

Ultrasound-Responsive Nanodroplet-Based Targeted Therapy via Conversion to Microbubbles

Ultrasound-based therapy is appealing as it can be used via a wireless approach at remote parts of the body including the brain. Microbubbles are commonly used in such therapy due to their highly sound-responsive property. However, the larger size of microbubbles limits selective targeting in vitro/in vivo. Here, we report the design of nanodroplets of 70-130 nm in size that can be easily converted to microbubbles via ultrasound exposure. The advantage of this approach is that smaller nanodroplets can be used for cell/subcellular targeting, and next, they can be used for therapy by converting to microbubbles. More specifically, folate/dopamine-terminated perfluorohexane nanodroplets are designed that are loaded with a molecular drug. These nanodroplets are used for selective cell targeting, followed by ultrasound-induced microbubble conversion that is associated with drug release and intracellular reactive oxygen species generation. This approach has been used for selective cell therapy applications. The designed nanodroplet and approach can be used for the enhanced therapeutic performance of existing drugs.

Nanotechnology translation in vascular diseases: From design to the bench

Atherosclerosis is a systemic pathophysiological condition contributing to the development of majority of polyvascular diseases. Nanomedicine is a novel and rapidly developing science. Due to their small size, nanoparticles are freely transported in vasculature, and have been widely employed as tools in analytical imaging techniques. Furthermore, the application of nanoparticles also allows target intervention, such as drug delivery and tissue engineering regenerative methods, in the management of major vascular diseases. Therefore, by summarizing the physical and chemical characteristics of common nanoparticles used in diagnosis and treatment of vascular diseases, we discuss the details of these applications from cellular, molecular, and in vivo perspectives in this review. Furthermore, we also summarize the status and challenges of the application of nanoparticles in clinical translation. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Cardiovascular Disease Implantable Materials and Surgical Technologies > Nanomaterials and Implants Therapeutic Approaches and Drug Discovery > Emerging Technologies.

Cancer Immunotherapy Based on Cell Membrane-Coated Nanocomposites Augmenting cGAS/STING Activation by Efferocytosis Blockade

Innate immunity triggered by the cGAS/STING pathway has the potential to improve cancer immunotherapy. Previously, the authors reported that double-stranded DNA (dsDNA) released by dying tumor cells can trigger the cGAS/STING pathway. However, owing to efferocytosis, dying tumor cells are engulfed and cleared before the damaged dsDNA is released; hence, immunologic tolerance and immune escape occur. Herein, a cancer-cell-membrane biomimetic nanocomposites that exhibit tumor-immunotherapeutic effects are synthesized by augmenting the cGAS/STING pathway and suppressing efferocytosis. Once internalized by cancer cells, a combined chemo/chemodynamic therapy would be triggered, which damages their nuclear and mitochondrial DNA. Furthermore, the releasing Annexin A5 protein could inhibit efferocytosis effect and promote immunostimulatory secondary necrosis by preventing phosphatidylserine exposure, resulting in the burst release of dsDNA. These dsDNA fragments, as molecular patterns to immunogenic damage, escape from the cancer cells, activate the cGAS/STING pathway, enhance cross-presentation inside dendritic cells, and promote M1-polarization of tumor-associated macrophages. In vivo experiments suggest that the proposed nanocomposite could recruit cytotoxic T-cells and facilitate long-term immunological memory. Moreover, when combined with immune-checkpoint blockades, it could augment the immune response. Therefore, this novel biomimetic nanocomposite is a promising strategy for generating adaptive antitumor immune responses.

Focused ultrasound-mediated blood-brain barrier opening combined with magnetic targeting cytomembrane based biomimetic microbubbles for glioblastoma therapy

Glioblastoma is the most common type of brain tumor. Due to the presence of the blood-brain barrier, the effects of chemotherapy have been unsatisfactory. The combination of focused ultrasound and microbubbles to reversibly open the blood-brain barrier is now considered a key factor in improving treatment outcomes of glioblastoma. In this study, we developed bionic drug delivery microbubbles, which in combination with focused ultrasound had an obvious inhibitory effect on glioblastoma. We extracted the brain microvascular cell membranes, combined them with lipid components, and loaded them with superparamagnetic iron oxide and doxorubicin to prepare biomimetic drug delivery microbubbles (FeDOX@cellMBs). We demonstrated that FeDOX@cellMBs retained the intrinsic properties of loading, such as magnetic properties and drug toxicity, both in vitro and in vivo. FeDOX@cellMBs exhibited good tumor targeting and uptake under the combined action of magnetic and focused ultrasound. Importantly, the FeDOX@cellMBs demonstrated excellent internal stability and effectively inhibited tumor growth in orthotopic glioblastoma mice. Finally, organ H&E staining confirmed that FeDOX@cellMBs were safe for use. In conclusion, FeDOX@cellMBs successfully penetrated the blood-brain barrier and effectively inhibited glioblastoma growth under the combined effects of focused ultrasound and magnetic stimulation. These results provide a new approach for the treatment of glioblastoma, with implications for future clinical translation.

Transferrin-targeted iridium nanoagglomerates with multi-enzyme activities for cerebral ischemia-reperfusion injury therapy

Cerebral ischemia-reperfusion injury (CIRI) is a complex pathological condition with high mortality. In particular, reperfusion can stimulate overproduction of reactive oxygen species (ROS) and activation of inflammation, causing severe secondary injuries to the brain. Despite tremendous efforts, it remains urgent to rationally design antioxidative agents with straightforward and efficient ROS scavenging capability. Herein, a potent antioxidative agent was explored based on iridium oxide nano-agglomerates (Tf-IrO2 NAs) via the facile transferrin (Tf)-templated biomineralization approach, and innovatively applied to treat CIRI. Containing some small-size IrO2 aggregates, these NAs possess intrinsic hydroxyl radicals (•OH)-scavenging ability and multifarious enzyme activities, such as catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GPx). Moreover, they also showed improved blood-brain barrier (BBB) penetration and enhanced accumulation in the ischemic brain via Tf receptor-mediated transcytosis. Therefore, Tf-IrO2 NAs achieved robust in vitro anti-inflammatory and cytoprotection effects against oxidative stress. Importantly, mice were effectively protected against CIRI by enhanced ROS scavenging activity in vivo, and the therapeutic mechanism was systematically verified. These findings broaden the idea of expanding Ir-based NAs as potent antioxidative agents to treat CIRI and other ROS-mediated diseases. STATEMENT OF SIGNIFICANCE: (1) The ROS-scavenging activities of IrO2 are demonstrated comprehensively, which enriched the family of nano-antioxidants. (2) The engineering Tf-IrO2 nano-agglomerates present unique multifarious enzyme activities and simultaneous transferrin targeting and BBB crossing ability for cerebral ischemia-reperfusion injury therapy. (3) This work may open an avenue to enable the use of IrO2 to alleviate ROS-mediated inflammatory and brain injury diseases.

Open source board based acoustofluidic transwells for reversible disruption of the blood-brain barrier for therapeutic delivery

BACKGROUND

Blood-brain barrier (BBB) is a crucial but dynamic structure that functions as a gatekeeper for the central nervous system (CNS). Managing sufficient substances across the BBB is a major challenge, especially in the development of therapeutics for CNS disorders.

METHODS

To achieve an efficient, fast and safe strategy for BBB opening, an acoustofluidic transwell (AFT) was developed for reversible disruption of the BBB. The proposed AFT was consisted of a transwell insert where the BBB model was established, and a surface acoustic wave (SAW) transducer realized using open-source electronics based on printed circuit board techniques.

RESULTS

In the AFT device, the SAW produced acousto-mechanical stimulations to the BBB model resulting in decreased transendothelial electrical resistance in a dose dependent manner, indicating the disruption of the BBB. Moreover, SAW stimulation enhanced transendothelial permeability to sodium fluorescein and FITC-dextran with various molecular weight in the AFT device. Further study indicated BBB opening was mainly attributed to the apparent stretching of intercellular spaces. An in vivo study using a zebrafish model demonstrated SAW exposure promoted penetration of sodium fluorescein to the CNS.

CONCLUSIONS

In summary, AFT effectively disrupts the BBB under the SAW stimulation, which is promising as a new drug delivery methodology for neurodegenerative diseases.

Remote control of the recruitment and capture of endogenous stem cells by ultrasound for in situ repair of bone defects

Stem cell-based tissue engineering has provided a promising platform for repairing of bone defects. However, the use of exogenous bone marrow mesenchymal stem cells (BMSCs) still faces many challenges such as limited sources and potential risks. It is important to develop new approach to effectively recruit endogenous BMSCs and capture them for in situ bone regeneration. Here, we designed an acoustically responsive scaffold (ARS) and embedded it into SDF-1/BMP-2 loaded hydrogel to obtain biomimetic hydrogel scaffold complexes (BSC). The SDF-1/BMP-2 cytokines can be released on demand from the BSC implanted into the defected bone via pulsed ultrasound (p-US) irradiation at optimized acoustic parameters, recruiting the endogenous BMSCs to the bone defected or BSC site. Accompanied by the daily p-US irradiation for 14 days, the alginate hydrogel was degraded, resulting in the exposure of ARS to these recruited host stem cells. Then another set of sinusoidal continuous wave ultrasound (s-US) irradiation was applied to excite the ARS intrinsic resonance, forming highly localized acoustic field around its surface and generating enhanced acoustic trapping force, by which these recruited endogenous stem cells would be captured on the scaffold, greatly promoting them to adhesively grow for in situ bone tissue regeneration. Our study provides a novel and effective strategy for in situ bone defect repairing through acoustically manipulating endogenous BMSCs.

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We designed ARS and embedded it into SDF-1/BMP-2 loaded hydrogel to form BSC.

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The BSC can release SDF-1/BMP-2 by p-US irradiation for recruitment of endogenous BMSCs and capture them by s-US irradiation.

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The in situ repair of bone defects were successfully realized by US-mediated control of the recruitment and capture of BMSCs.

Barrier-breaking effects of ultrasonic cavitation for drug delivery and biomarker release

Recently, emerging evidence has demonstrated that cavitation actually creates important bidirectional channels on biological barriers for both intratumoral drug delivery and extratumoral biomarker release. To promote the barrier-breaking effects of cavitation for both therapy and diagnosis, we first reviewed recent technical advances of ultrasound and its contrast agents (microbubbles, nanodroplets, and gas-stabilizing nanoparticles) and then reported the newly-revealed cavitation physical details. In particular, we summarized five types of cellular responses of cavitation in breaking the plasma membrane (membrane retraction, sonoporation, endocytosis/exocytosis, blebbing and apoptosis) and compared the vascular cavitation effects of three different types of ultrasound contrast agents in breaking the blood-tumor barrier and tumor microenvironment. Moreover, we highlighted the current achievements of the barrier-breaking effects of cavitation in mediating drug delivery and biomarker release. We emphasized that the precise induction of a specific cavitation effect for barrier-breaking was still challenged by the complex combination of multiple acoustic and non-acoustic cavitation parameters. Therefore, we provided the cutting-edge in-situ cavitation imaging and feedback control methods and suggested the development of an international cavitation quantification standard for the clinical guidance of cavitation-mediated barrier-breaking effects.

Preparation of gastrodin-modified dendrimer-entrapped gold nanoparticles as a drug delivery system for cerebral ischemia-reperfusion injury

OBJECTIVE

This study sought to evaluate the feasibility of multifunctional gastrodin (GAS)-containing nano-drug carrier system against cerebral ischemia-reperfusion injury (CIRI).

METHODS

The drug-loaded nanocomposite (Au-G5.NHAc-PS/GAS) with certain encapsulation efficiency (EE) was prepared by physical adsorption method using different proportions of GAS and drug-carrying system (Au-G5.NHAc-PS). High-performance liquid chromatography was used to determine the drug loading and EE. Cultured rat astrocytes and hypothalamic neurons were assigned into four groups: PBS, Au-G5.NHAc-PS, Au-G5.NHAc-PS/GAS, and GAS. CCK-8 assay, flow cytometry, and quantitative real-time PCR were performed to examine the cell viability, apoptosis, and the expression of tumor necrosis factor-α (TNF-α), IL-1β, and IL-6 in the astrocytes and hypothalamic neurons, respectively. Cellular uptake of GAS and Au-G5.NHAc-PS/GAS was analyzed by using Hoechst 33342 staining. The animal model with focal cerebral ischemia was generated by middle cerebral artery occlusion (MCAO) in healthy male Sprague Dawley (SD) rats, and pathological changes of brain tissue and major organs in the rats were identified by hematoxylin and eosin (HE) staining. Apoptosis in rat astrocytes and hypothalamic neurons was detected by TUNEL staining and flow cytometry.

RESULTS

Au-G5.NHAc-PS had a spherical shape with a uniform size of 157.3 nm. Among the nanoparticles, Au-G5.NHAc-PS/GAS with an EE of 70.3% displayed the best release delay effect. Moreover, we observed that in vitro cytotoxicity and cellular uptake of Au-G5.NHAc-PS/GAS were higher than those of GAS, whereas the expression of TNF-α, IL-1β, and IL-6 was significantly downregulated in Au-G5.NHAc-PS/GAS group as compared to G5.NHAc-PS group. Notably, HE staining revealed that although Au-G5.NHAc-PS/GAS had no toxic and side effects on the main organs of rats, it alleviated the damage of brain tissue in the MCAO rats. Besides, Au-G5.NHAc/GAS markedly reduced MCAO-induced apoptosis.

CONCLUSION

Au-G5.NHAc-PS showed favorable surface morphology, sustained drug release ability, no measurable toxicity, and good biocompatibility, indicating that GAS exerts anti-inflammatory and antiapoptotic effects on CIRI.

NIR-II fluorescence visualization of ultrasound-induced blood-brain barrier opening for enhanced photothermal therapy against glioblastoma using indocyanine green microbubbles

Focused ultrasound (FUS)-induced blood-brain barrier (BBB) opening is crucial for enhancing glioblastoma (GBM) therapies. However, an in vivo imaging approach with a high spatial-temporal resolution to monitor the BBB opening process in situ and synchronously is still lacking. Herein, we report the use of indocyanine green (ICG)-dopped microbubbles (MBs-ICG) for visualizing the FUS-induced BBB opening and enhancing the photothermal therapy (PTT) against GBM. The MBs-ICG show bright fluorescence in the second near-infrared window (NIR-II), ultrasound contrast, and ultrasound-induced size transformation properties. By virtue of complementary contrast properties, MBs-ICG can be successfully applied for cerebral vascular imaging with NIR-II fluorescence resolution of ∼168.9 μm and ultrasound penetration depth of ∼7 mm. We further demonstrate that MBs-ICG can be combined with FUS for in situ and synchronous visualization of the BBB opening with a NIR-II fluorescence signal-to-background ratio of 6.2 ± 1.2. Finally, our data show that the MBs-ICG transform into lipid-ICG nanoparticles under FUS irradiation, which then rapidly penetrate the tumor tissues within 10 min and enhance PTT in orthotopic GBM-bearing mice. The multifunctional MBs-ICG approach provides a novel paradigm for monitoring BBB opening and enhancing GBM therapy.

Ultrasound-mediated blood-brain barrier opening: An effective drug delivery system for theranostics of brain diseases

Blood-brain barrier (BBB) remains a significant obstacle to drug therapy for brain diseases. Focused ultrasound (FUS) combined with microbubbles (MBs) can locally and transiently open the BBB, providing a potential strategy for drug delivery across the BBB into the brain. Nowadays, taking advantage of this technology, many therapeutic agents, such as antibodies, growth factors, and nanomedicine formulations, are intensively investigated across the BBB into specific brain regions for the treatment of various brain diseases. Several preliminary clinical trials also have demonstrated its safety and good tolerance in patients. This review gives an overview of the basic mechanisms, ultrasound contrast agents, evaluation or monitoring methods, and medical applications of FUS-mediated BBB opening in glioblastoma, Alzheimer's disease, and Parkinson's disease.

Antitumor effects of Chinese herbal medicine compounds and their nano-formulations on regulating the immune system microenvironment

Traditional Chinese medicine (TCM), including herbal medicine, acupuncture and meditation, has a wide range of applications in China. In recent years, herbal compounding and active ingredients have been used to control tumor growth, reduce suffering, improve quality of life, and prolong the life span of cancer patients. To reduce side effects, herbal medicine can be used in conjunction with radiotherapy and chemotherapy or can be used as an adjuvant to strengthen the immune effect of anticancer vaccines. In particular, in the immunosuppressed tumor microenvironment, herbal medicine can have antitumor effects by stimulating the immune response. This paper reviews the advances in research on antitumor immunomodulation in Chinese herbal medicine, including the regulation of the innate immune system, which includes macrophages, MDSCs, and natural killer cells, and the adaptive immune system, which includes CD4+ T cells, CD8+ T cells, and regulatory T cells (Tregs), to influence tumor-associated inflammation. In addition, a combination of active ingredients of herbal medicine and modern nanotechnology alter the tumor immune microenvironment. In recent years, immunological antitumor therapy in TCM has been applied on a reasonably large scale both nationally and internationally, and there is potential for further clinical expansion. Investigation of immune modulation mechanisms in Chinese herbal medicine will provide novel perspectives of how herbal medicine controls tumor growth and metastasis, which will contribute to the evolution of tumor research.

Gastrodin and Vascular Dementia: Advances and Current Perspectives

Gastrodia elata, a traditional Chinese medicine, has been widely used since ancient times to treat diseases such as dizziness, epilepsy, stroke, and memory loss. Gastrodin, one of the active components of Gastrodia elata, has been used in the treatment of migraine, epilepsy, Parkinson's disease, dementia, and depression in recent years. It can improve cognitive function and related neuropsychiatric symptoms through various effects and is considered as a promising treatment for dementia. Vascular dementia is a kind of severe cognitive impairment syndrome caused by vascular factors, and it is the dementia syndrome with the largest number of patients besides Alzheimer's disease. Although there is still a lack of evidence-based explorations, the paper reviewed the mechanism and methods of gastrodin in the treatment of vascular dementia, providing a reference for clinical therapy.

Oxygen-carrying biomimetic nanoplatform for sonodynamic killing of bacteria and treatment of infection diseases

Among various novel antimicrobial therapies, sonodynamic therapy (SDT) exhibits its advantages for the treatment of bacterial infections due to its high penetration depth and low side effects. In this study, a new nanosonosensitizer (HFH@ZIF-8) that loads sonosensitizer hematoporphyrin monomethyl ether (HMME) into zeolitic imidazolate framework-8 (ZIF-8), was constructed for killing multidrug-resistant (MDR) bacteria and treatment of in vivo infection diseases by SDT. In particular, the developed HFH@ZIF-8 exhibited enhanced water-solubility, good biocompatibility, and improved disease-targeting capability for delivering and releasing HMME and ablating the infected lesion. More importantly, the presence of oxygen-carrying hemoglobin for HFH@ZIF-8 can offer sufficient oxygen consumption by SDT, augmenting the efficacy of SDT by improving ROS generating efficiency against deep tissue multidrug-resistant bacterial infection. Therefore, this study paves a new avenue for treating infection disease, particularly for antibiotic resistant bacterial infection.