Enhanced delivery to brain using sonosensitive liposome and microbubble with focused ultrasound

Study on ultrasound-enhanced molecular transport in articular cartilage

Local intra-articular administration with minimal side effects and rapid efficacy is a promising strategy for treating osteoarthritis(OA). Most drugs are rapidly cleared from the joint space by capillaries and lymphatic vessels before free diffusion into cartilage. Ultrasound, as a non-invasive therapy, enhances molecular transport within cartilage through the mechanisms of microbubble cavitation and thermal effects. This study investigated the mass transfer behavior of solute molecules with different molecular weights (479 Da, 40 kDa, 150 kDa) within porcine articular cartilage under low-frequency ultrasound conditions of 40 kHz and ultrasound intensities of 0.189 W/cm2 and 0.359 W/cm2. The results revealed that under the conditions of 0.189 W/cm2 ultrasound intensity, the mass transfer concentration of solute molecules were higher compared to passive diffusion, and with an increase in ultrasound intensity to 0.359 W/cm2, the mass transfer effect within the cartilage was further enhanced. Ultrasound promotes molecular transport in different layers of cartilage. Under static conditions, after 2 h of mass transfer, the concentration of small molecules in the superficial layer is lower than that in the middle layer. After applying ultrasound at 0.189 W/cm2, the molecular concentration in the superficial layer significantly increases. Under conditions of 0.359 W/cm2, after 12 h of mass transfer, the concentration of medium and large molecules in the deep layer region increased by more than two times. In addition, this study conducted an assessment of damage to porcine articular cartilage under ultrasound exposure, revealing the significant potential of low-frequency, low-intensity ultrasound in drug delivery and treatment of OA.

Blood Brain Barrier-Crossing Delivery of Felodipine Nanodrug Ameliorates Anxiety-Like Behavior and Cognitive Impairment in Alzheimer's Disease

Alzheimer's disease (AD) is the most common age-related neurodegenerative disorder leading to cognitive decline. Excessive cytosolic calcium (Ca2+) accumulation plays a critical role in the pathogenesis of AD since it activates the NOD-like receptor family, pyrin domain containing 3 (NLRP3), switches the endoplasmic reticulum (ER) unfolded protein response (UPR) toward proapoptotic signaling and promotes Aβ seeding. Herein, a liposomal nanodrug (felodipine@LND) is developed incorporating a calcium channel antagonist felodipine for Alzheimer's disease treatment through a low-intensity pulse ultrasound (LIPUS) irradiation-assisted blood brain barrier (BBB)-crossing drug delivery. The multifunctional felodipine@LND is effectively delivered to diseased brain through applying a LIPUS irradiation to the skull, which resulted in a series of positive effects against AD. Markedly, the nanodrug treatment switched the ER UPR toward antioxidant signaling, prevented the surface translocation of ER calreticulin (CALR) in microglia, and inhibited the NLRP3 activation and Aβ seeding. In addition, it promoted the degradation of damaged mitochondria via mitophagy, thereby inhibiting the neuronal apoptosis. Therefore, the anxiety-like behavior and cognitive impairment of 5xFAD mice with AD is significantly ameliorated, which manifested the potential of LIPUS - assisted BBB-crossing delivery of felodipine@LND to serve as a paradigm for AD therapy based on the well-recognized clinically available felodipine.

Current Non-Metal Nanoparticle-Based Therapeutic Approaches for Glioblastoma Treatment

The increase in the variety of nano-based tools offers new possibilities to approach the therapy of poorly treatable tumors, which includes glioblastoma multiforme (GBM; a primary brain tumor). The available nanocomplexes exhibit great potential as vehicles for the targeted delivery of anti-GBM compounds, including chemotherapeutics, nucleic acids, and inhibitors. The main advantages of nanoparticles (NPs) include improved drug stability, increased penetration of the blood-brain barrier, and better precision of tumor targeting. Importantly, alongside their drug-delivery ability, NPs may also present theranostic properties, including applications for targeted imaging or photothermal therapy of malignant brain cells. The available NPs can be classified into two categories according to their core, which can be metal or non-metal based. Among non-metal NPs, the most studied in regard to GBM treatment are exosomes, liposomes, cubosomes, polymeric NPs, micelles, dendrimers, nanogels, carbon nanotubes, and silica- and selenium-based NPs. They are characterized by satisfactory stability and biocompatibility, limited toxicity, and high accumulation in the targeted tumor tissue. Moreover, they can be easily functionalized for the improved delivery of their cargo to GBM cells. Therefore, the non-metal NPs discussed here, offer a promising approach to improving the treatment outcomes of aggressive GBM tumors.

Overcoming Barriers in Glioblastoma-Advances in Drug Delivery Strategies

The world of cancer treatment is evolving rapidly and has improved the prospects of many cancer patients. Yet, there are still many cancers where treatment prospects have not (or hardly) improved. Glioblastoma is the most common malignant primary brain tumor, and even though it is sensitive to many chemotherapeutics when tested under laboratory conditions, its clinical prospects are still very poor. The blood-brain barrier (BBB) is considered at least partly responsible for the high failure rate of many promising treatment strategies. We describe the workings of the BBB during healthy conditions and within the glioblastoma environment. How the BBB acts as a barrier for therapeutic options is described as well as various approaches developed and tested for passing or opening the BBB, with the ultimate aim to allow access to brain tumors and improve patient perspectives.

Nanoparticle-based materials in anticancer drug delivery: Current and future prospects

The past decade has witnessed a breakthrough in novel strategies to treat cancer. One of the most common cancer treatment modalities is chemotherapy which involves administering anti-cancer drugs to the body. However, these drugs can lead to undesirable side effects on healthy cells. To overcome this challenge and improve cancer cell targeting, many novel nanocarriers have been developed to deliver drugs directly to the cancerous cells and minimize effects on the healthy tissues. The majority of the research studies conclude that using drugs encapsulated in nanocarriers is a much safer and more effective alternative than delivering the drug alone in its free form. This review provides a summary of the types of nanocarriers mainly studied for cancer drug delivery, namely: liposomes, polymeric micelles, dendrimers, magnetic nanoparticles, mesoporous nanoparticles, gold nanoparticles, carbon nanotubes and quantum dots. In this review, the synthesis, applications, advantages, disadvantages, and previous studies of these nanomaterials are discussed in detail. Furthermore, the future opportunities and possible challenges of translating these materials into clinical applications are also reported.

Unveiling the enigma of the blood-brain barrier in glioblastoma: current advances from preclinical and clinical studies

PURPOSE OF REVIEW

Glioblastoma (GBM), the most prevalent primary brain malignancy in adults, poses significant challenges in terms of treatment. Current therapeutic strategies for GBM patients involve maximal safe resection, followed by radiotherapy with concurrent and adjuvant temozolomide. However, despite this multimodal approach for GBM, the prognosis of GBM patients remains dismal because of their inherent primary and secondary resistances to treatments.

RECENT FINDINGS

Several molecular and cellular mechanisms, including the presence of the blood-brain barrier (BBB), contribute to these resistances. The BBB, comprising multiple layers surrounding brain vessels, acts as a barrier limiting effective drug delivery to the brain. Invasive and noninvasive tools to deliver drugs and pharmaceutical formulations locally or systemically are continuously evolving to overcome the BBB in GBM toward improving drug bioavailability in the brain and reducing systemic toxicities.

SUMMARY

Preliminary studies utilizing these approaches have demonstrated promising results in terms of safety and signals of efficacy during early-phase clinical trials. However, further work through additional clinical trials is necessary to evaluate the potential clinical benefits for GBM patients.

Drug delivery by sonosensitive liposome and microbubble with acoustic-lens attached ultrasound: an in vivo feasibility study in a murine melanoma model

Conventional chemotherapy methods have adverse off-target effects and low therapeutic efficiencies of drug release in target tumors. In this study, we proposed a combination therapy of doxorubicin (DOX)-loaded ultrasound (US)-sensitive liposomal nanocarriers (IMP301), microbubbles (MBs) under focused US exposure using convex acoustic lens-attached US (LENS) to tumor treatment. The therapeutic effects of each treatment in a murine melanoma model were evaluated using contrast-enhanced US (CEUS) and micro-computed tomography (micro-CT) imaging, bioluminescence and confocal microscopy imaging, and liquid chromatography-mass spectroscopy (LC/MS) analysis. Tumor-bearing mice were randomly assigned to one of the following groups: (1) G1: IMP301 only (n = 9); (2) G2: IMP301 + LENS (n = 9); (3) G3: IMP301 + MB + LENS (n = 9); (4) G4: DOXIL only (n = 9); and (5) G5: IMP301 without DOXIL group as a control group (n = 4). Ten days after tumor injection, tumor-bearing mice were treated according to each treatment strategy on 10th, 12th, and 14th days from the day of tumor injection. The CEUS images of the tumors in the murine melanoma model clearly showed increased echo signal intensity from MBs as resonant US scattering. The relative tumor volume of the G2 and G3 groups on the micro-CT imaging showed inhibited tumor growth than the reference baseline of the G5 group. DOX signals on bioluminescence and confocal microscopy imaging were mainly located at the tumor sites. LC/MS showed prominently higher intratumoral DOX concentration in the G3 group than in other treated groups. Therefore, this study effectively demonstrates the feasibility of the synergistic combination of IMP301, MBs, and LENS-application for tumor-targeted treatment. Thus, this study can enable efficient tumor-targeted treatment by combining therapy such as IMP301 + MBs + LENS-application.

Modulation of engineered nanomaterial interactions with organ barriers for enhanced drug transport

The biomedical use of nanoparticles (NPs) has been the focus of intense research for over a decade. As most NPs are explored as carriers to alter the biodistribution, pharmacokinetics and bioavailability of associated drugs, the delivery of these NPs to the tissues of interest remains an important topic. To date, the majority of NP delivery studies have used tumor models as their tool of interest, and the limitations concerning tumor targeting of systemically administered NPs have been well studied. In recent years, the focus has also shifted to other organs, each presenting their own unique delivery challenges to overcome. In this review, we discuss the recent advances in leveraging NPs to overcome four major biological barriers including the lung mucus, the gastrointestinal mucus, the placental barrier, and the blood-brain barrier. We define the specific properties of these biological barriers, discuss the challenges related to NP transport across them, and provide an overview of recent advances in the field. We discuss the strengths and shortcomings of different strategies to facilitate NP transport across the barriers and highlight some key findings that can stimulate further advances in this field.

Overcoming the blood brain barrier in glioblastoma: Status and future perspective

Glioblastoma is the most common primary brain malignancy in adults. Treatment of glioblastoma patients is based on neurosurgery, radiation therapy and chemotherapy. Despite this multimodal therapeutic regimen, the prognosis of glioblastoma patients is poor. Indeed, glioblastoma is very resistant to treatments due to multiple molecular and cellular mechanisms including the existence of the blood-brain barrier (BBB). The BBB consists of multiple layers surrounding brain vessels and limits drug penetration within the brain. Therefore, overcoming the BBB is a strategy to increase bioavailability and efficacy of therapeutic agents against glioblastoma cells. The development of two approaches is ongoing: i) enhancing the delivery of drugs to the brain and ii) improving the penetration of drugs into the brain. One way to enhance drug delivery to the brain is through high-dose intravenous chemotherapy, with or without bone marrow transplantation, or via intra-arterial chemotherapy, with or without disrupting the BBB through osmotic means. Conversely, improving drug penetration within the brain can be achieved through modifying either the drug itself or the BBB. Promising results in terms of safety and signals of efficacy were obtained with these approaches in early phase clinical trials. More advanced comparative clinical trials are needed to investigate the clinical benefit for glioblastoma patients.

Microbubble Delivery Platform for Ultrasound-Mediated Therapy in Brain Cancers

The blood-brain barrier (BBB) is one of the most selective endothelial barriers that protect the brain and maintains homeostasis in neural microenvironments. This barrier restricts the passage of molecules into the brain, except for gaseous or extremely small hydrophobic molecules. Thus, the BBB hinders the delivery of drugs with large molecular weights for the treatment of brain cancers. Various methods have been used to deliver drugs to the brain by circumventing the BBB; however, they have limitations such as drug diversity and low delivery efficiency. To overcome this challenge, microbubbles (MBs)-based drug delivery systems have garnered a lot of interest in recent years. MBs are widely used as contrast agents and are recently being researched as a vehicle for delivering drugs, proteins, and gene complexes. The MBs are 1-10 μm in size and consist of a gas core and an organic shell, which cause physical changes, such as bubble expansion, contraction, vibration, and collapse, in response to ultrasound. The physical changes in the MBs and the resulting energy lead to biological changes in the BBB and cause the drug to penetrate it, thus enhancing the therapeutic effect. Particularly, this review describes a state-of-the-art strategy for fabricating MB-based delivery platforms and their use with ultrasound in brain cancer therapy.

Preclinical Research on Focused Ultrasound-Mediated Blood-Brain Barrier Opening for Neurological Disorders: A Review

Several therapeutic agents for neurological disorders are usually not delivered to the brain owing to the presence of the blood-brain barrier (BBB), a special structure present in the central nervous system (CNS). Focused ultrasound (FUS) combined with microbubbles can reversibly and temporarily open the BBB, enabling the application of various therapeutic agents in patients with neurological disorders. In the past 20 years, many preclinical studies on drug delivery through FUS-mediated BBB opening have been conducted, and the use of this method in clinical applications has recently gained popularity. As the clinical application of FUS-mediated BBB opening expands, it is crucial to understand the molecular and cellular effects of FUS-induced microenvironmental changes in the brain so that the efficacy of treatment can be ensured, and new treatment strategies established. This review describes the latest research trends in FUS-mediated BBB opening, including the biological effects and applications in representative neurological disorders, and suggests future directions.

Sonosensitive Phase-Changeable Nanoparticle Mediated Enhanced Chemotherapy in Prostate Cancer by Low-Intensity Focused Ultrasound

Prostate cancer (PCa) is one of the most common cancer types. Early detection of PC offers the best chance of successful treatment. A noninvasive, image-guided therapy mediated by targeted nanoparticles (NPs) has the potential to improve the efficacy and safety of cancer therapies. Herein, we report a sonosensitive nanoparticle modified with anti-PSMA (prostate-specific membrane antigen) antibodies to activate target prostate tumors. These nanoparticles (PFP@IR780@PTX@liposome NPs) were co-loaded with the chemotherapeutic agent docetaxel and the sonosensitizer IR780, as well as phase-changeable perfluorocarbon (PFC) liquids. The liquid-gas phase change could be induced by low-intensity focused ultrasound (LIFU) in vitro. We found that the PFP@IR780@PTX@liposome NPs can specifically accumulate in prostate tumors after LIFU irradiation, as monitored by ultrasound and photoacoustic imaging. Meanwhile, docetaxel was controllably released from the nanoparticles to achieve enhanced chemotherapeutic therapy in vivo. These sonosensitive phase-changeable NPs can visually treat prostate cancers effectively and have a clinical potential.

New insight into brain disease therapy: nanomedicines-crossing blood-brain barrier and extracellular space for drug delivery

INTRODUCTION

Brain diseases including brain tumor, Alzheimer's disease, Parkinson's disease, etc. are difficult to treat. The blood-brain barrier (BBB) is a major obstacle for drug delivery into the brain. Although nano-package and receptor-mediated delivery of nanomedicine markedly increases BBB penetration, it yet did not extensively improve clinical cure rate. Recently, brain extracellular space (ECS) and interstitial fluid (ISF) drainage in ECS have been found to determine whether a drug dissolved in ISF can reach its target cells. Notably, an increase in tortuosity of ECS associated with slower ISF drainage induced by the accumulated harmful substances, such as: amyloid-beta (Aβ), α-synuclein, and metabolic wastes, causes drug delivery failure.

AREAS COVERED

The methods of nano-package and receptor-mediated drug delivery and the penetration efficacy of nanomedicines across BBB and ECS are assessed.

EXPERT OPINION

Invasive delivering drug via ECS and noninvasive near-infrared photo-sensitive nanomedicines may provide a promising benefit to patients with brain disease.