Targeting Nanoparticles to Bioengineered Human Vascular Networks

Enhanced sclerotherapy for vascular malformations: A dual-mechanism approach using in-situ forming PATDs gel

Vascular malformations are common vascular lesions in infants and seriously affect their health and quality of life. Vascular sclerotherapy is an effective treatment for vascular malformations. However, current sclerosants have difficulty achieving both high efficiency and low toxicity, and their dosing forms make it difficult to achieve long-term retention in the affected blood vessels. Therefore, exploring a safe and effective sclerosant and its delivery strategy is the key to clinical sclerotherapy. To address the above issues, this study developed sclerosants that could form an in-situ gel based on a dual mechanism of vascular injury and plasmin (PLA) inhibition. By linking the non-ionic surfactant sclerosant polyoxyethylene alkyl ether (PAs) and the PLA inhibitor tranexamic acid (TA) through an ester bond, a cationic surfactant sclerosant polyoxyethylene alkylether tranexamate derivatives (PATDs) were constructed. The cationic charge of PATDs enhanced its cytotoxicity to HUVEC-TIE2-L914F cells, and the ester bond of PATDs could be degraded by esterase in the blood, reducing its systemic toxicity. The degradation product TA inhibited the activation of the PLA-matrix metalloproteinase (MMPs) system induced by vascular injury, thereby promoting the deposition of collagen and the proliferation and differentiation of fibroblasts to promote vascular fibrosis. In addition, an injectable solution (PATDs/GA) was prepared by mixing PATDs with glycerol formaldehyde (GA), and PATDs/GA could form a low-molecular-weight gel automatically in an aqueous solution, which was beneficial to increase its retention in the affected blood vessels and reduce the risk of drug entering non-targeted sites. At the same time, this gel automatically dissolved, reducing the risk of immune rejection caused by long-term retention. This study provided a new and precise approach for the treatment of vascular sclerosis with high efficiency and low toxicity.

Size-dependent Nanoparticle Accumulation In Venous Malformations

Objective

The current treatment of venous malformations (VMs) consists of medications with systemic toxicity and procedural interventions with high technical difficulty and risk of hemorrhage. Using nanoparticles (NPs) to enhance drug delivery to VMs could enhance efficacy and decrease systemic toxicity. NPs can accumulate in tissues with abnormal vasculature, a concept known as the enhanced permeation and retention (EPR) effect. EPR has been documented in tumors, bioengineered vessels, and VMs. However, in VMs, it is unknown if NP size affects EPR and if so, which particle size improves NP accumulation.

Methods

In this study, we used a murine model of subcutaneous VMs using human umbilical vein endothelial cells that express the most frequent VM-causing tyrosine kinase with immunoglobulin and EGF homology domains mutation, tyrosine kinase with immunoglobulin and EGF homology domains-L914F. Hollow silica NPs coated in polyethylene glycol (PEG) and conjugated to a fluorophore were administered systemically via tail vein injection. We studied the accumulation of a range of NP sizes within the VM and organs using confocal microscopy and an in vivo imaging system.

Results

The 20, 50, 80, and 180 nm PEGylated, fluorophore-tagged hollow silica NPs were spherical and had hydrodynamic diameters of 31.6 ± 0.9, 58.5 ± 0.1, 87.1 ± 2.4, and 232 ± 1.26 nm, respectively. Following systemic NP administration, 20 nm NPs had 2 times more fluorescence accumulation within VMs compared with 50 nm, and 6 times more fluorescence accumulation compared with larger (greater than 80 nm) NPs (P < .01).

Conclusion

This study helps to determine the optimal NP size for passive accumulation within VMs and lays the foundation for engineering NPs for the treatment of VMs.

Recent advances in nanomaterial-driven strategies for diagnosis and therapy of vascular anomalies

Nanotechnology has demonstrated immense potential in various fields, especially in biomedical field. Among these domains, the development of nanotechnology for diagnosing and treating vascular anomalies has garnered significant attention. Vascular anomalies refer to structural and functional anomalies within the vascular system, which can result in conditions such as vascular malformations and tumors. These anomalies can significantly impact the quality of life of patients and pose significant health concerns. Nanoscale contrast agents have been developed for targeted imaging of blood vessels, enabling more precise identification and characterization of vascular anomalies. These contrast agents can be designed to bind specifically to abnormal blood vessels, providing healthcare professionals with a clearer view of the affected areas. More importantly, nanotechnology also offers promising solutions for targeted therapeutic interventions. Nanoparticles can be engineered to deliver drugs directly to the site of vascular anomalies, maximizing therapeutic effects while minimizing side effects on healthy tissues. Meanwhile, by incorporating functional components into nanoparticles, such as photosensitizers, nanotechnology enables innovative treatment modalities such as photothermal therapy and photodynamic therapy. This review focuses on the applications and potential of nanotechnology in the imaging and therapy of vascular anomalies, as well as discusses the present challenges and future directions.

Nanocrystals for Deep-Tissue In Vivo Luminescence Imaging in the Near-Infrared Region

In vivo imaging technologies have emerged as a powerful tool for both fundamental research and clinical practice. In particular, luminescence imaging in the tissue-transparent near-infrared (NIR, 700-1700 nm) region offers tremendous potential for visualizing biological architectures and pathophysiological events in living subjects with deep tissue penetration and high imaging contrast owing to the reduced light-tissue interactions of absorption, scattering, and autofluorescence. The distinctive quantum effects of nanocrystals have been harnessed to achieve exceptional photophysical properties, establishing them as a promising category of luminescent probes. In this comprehensive review, the interactions between light and biological tissues, as well as the advantages of NIR light for in vivo luminescence imaging, are initially elaborated. Subsequently, we focus on achieving deep tissue penetration and improved imaging contrast by optimizing the performance of nanocrystal fluorophores. The ingenious design strategies of NIR nanocrystal probes are discussed, along with their respective biomedical applications in versatile in vivo luminescence imaging modalities. Finally, thought-provoking reflections on the challenges and prospects for future clinical translation of nanocrystal-based in vivo luminescence imaging in the NIR region are wisely provided.

Ablation of Venous Malformations by Photothermal Therapy with Intravenous Gold Nanoshells

Venous malformations (VMs) consist of hugely enlarged and dysmorphic veins. These lesions cause significant disfigurement, pain, and complications such as bleeding and coagulopathy. Pharmacotherapy for the treatment of VMs has limited efficacy and potentially limiting toxicity. Current treatment for patients with VMs entails life-long pharmacotherapy or surgical procedures. Here we explored whether intravenously administered agents can be used to destroy VMs by photothermal therapy (PTT), using gold nanoshells (AuNSs) that generated heat following irradiation with near-infrared (NIR) light. In a murine model of VMs, intravenous AuNSs accumulated within the VMs. Irradiation of the VMs induced marked regression and even elimination. Nanoparticle-based photothermal therapy can provide effective therapy for VMs, which are otherwise relatively refractory to treatment.

Photocleavage-based Photoresponsive Drug Delivery

Targeted drug delivery has been extensively studied in the last decade, whereas both passive and active targeting strategies still face many challenges, such as off-target drug release. Light-responsive drug delivery systems have been developed with high controllability and spatio-temporal resolution to improve drug efficacy and reduce off-target drug release. Photoremovable protecting groups are light-responsive moieties that undergo irreversible photocleavage reactions upon light irradiation. They can be covalently linked to the molecule of interest to control its structure and function with light. In this review, we will summarize recent applications of photocleavage technologies in nanoparticle-based drug delivery for precise targeting and controlled drug release, with a highlight of strategies to achieve long-wavelength light excitation. A greater understanding of these mechanisms and emerging studies will help design more efficient photocleavage-based nanosystems to advance photoresponsive drug delivery.

Transformable Helical Self-Assembly for Cancerous Golgi Apparatus Disruption

Golgi apparatus is a major subcellular organelle responsible for drug resistance. Golgi apparatus-targeted nanomechanical disruption provides an attractive approach for killing cancer cells by multimodal mechanism and avoiding drug resistance. Inspired by the poisonous twisted fibrils in Alzheimer's brain tissue and enhanced rigidity of helical structure in nature, we designed transformable peptide C₆RVRRF₄KY that can self-assemble into nontoxic nanoparticles in aqueous medium but transformed into left-handed helical fibrils (L-HFs) after targeting and furin cleavage in the Golgi apparatus of cancer cells. The L-HFs can mechanically disrupt the Golgi apparatus membrane, resulting in inhibition of cytokine secretion, collapse of the cellular structure, and eventually death of cancer cells. Repeated stimulation of the cancers by the precursors causes no acquired drug resistance, showing that mechanical disruption of subcellular organelle is an excellent strategy for cancer therapy without drug resistance. This nanomechanical disruption concept should also be applicable to multidrug-resistant bacteria and viruses.