Candidates for smart cardiovascular medical device coatings: A comparative study with endothelial and smooth muscle cells

Fe3O4 coated stent prevent artery neointimal hyperplasia by inhibiting vascular smooth muscle cell proliferation

In-stent restenosis (ISR), caused by aggressive vascular smooth muscle cell (VSMC) proliferation, is a serious complication of stenting. Therefore, developing therapeutic approaches that target VSMC inhibition is imperative. Our previous study showed that VSMC hyperplasia was attenuated after iron stent degradation, and VSMC proliferation around the stented section was arrested. The corrosion products of the iron stents were primarily Fe3O4 particles. Therefore, we hypothesized that Fe3O4 particles generated by iron stents would prevent neointimal hyperplasia by inhibiting VSMC proliferation. To test this hypothesis, culture assays and flow cytometry were performed to investigate the proliferation of VSMC. Global gene sequencing and Kyoto Encyclopedia of Genes and Genomes enrichment analyses were performed to investigate the underlying mechanisms. Fe3O4-coated stents were implanted into rabbit carotid arteries to evaluate the inhibitory effects of Fe3O4 on neointimal hyperplasia. The major findings of the study were as follows: 1) Fe3O4 attenuated neointimal hyperplasia by preventing VSMC proliferation after stenting; 2) Fe3O4 exerted inhibitory effects on VSMCs by downregulating proliferative genes such as SOX9, EGR4, and TGFB1, but upregulated inhibitory genes such as DNMT1, TIMP3, and PCNA; 3) Fe3O4 inhibited VSMCs by preventing phenotypic transformation from the contractile to the synthetic phase; and 4) Fe3O4-coated stents achieved satisfactory hemocompatibility in a rabbit model. Our study highlights the additional benefits of Fe3O4 particles in inhibiting VSMC proliferation, indicating that Fe3O4 coated stent potentially served as an attractive therapeutic approach for ISR prevention.

Evaluation of paclitaxel-coated balloon angioplasty for the treatment of symptomatic intracranial in-stent restenosis

Background

Symptomatic intracranial in-stent restenosis (sISR) poses a major challenge in the management of cerebrovascular diseases, often requiring effective and safe treatment options.

Objectives

This study aims to evaluate the efficacy and safety of paclitaxel-coated balloon (PCB) angioplasty for treating sISR.

Methods

We conducted a retrospective analysis of five patients aged 49-74 years, who were treated with PCB angioplasty between January 2017 and June 2022. Treatment procedures included pre-operative digital subtraction angiography, antiplatelet therapy, and the use of the SeQuent Please balloon. Patients received aspirin and clopidogrel prior to and after the procedure.

Results

The procedure achieved a 100% success rate. The degree of ISR was significantly reduced from an average pre-operative rate of 72±18.9% to a post-operative rate of 34±8.22%. Long-term follow-up showed that the majority of patients did not experience restenosis, confirming the long-term effectiveness of the treatment.

Conclusions

PCB angioplasty demonstrates significant potential as an effective and safe treatment option for patients with sISR, especially those considered to be at high risk. This study supports further investigation into PCB angioplasty as a standard treatment for sISR.

Research progress of metal biomaterials with potential applications as cardiovascular stents and their surface treatment methods to improve biocompatibility

Facing the growing issue of cardiovascular diseases, metallic materials with higher tensile strength and fatigue resistance play an important role in treating diseases. This review lists the advantages and drawbacks of commonly used medical metallic materials for vascular stents. To avoid post-procedural threats such as thrombosis and in-stent restenosis, surface treatments, and coating methods have been used to further improve the biocompatibility of these materials. Surface treatments including laser, plasma treatment, polishing, oxidization, and fluorination can improve biocompatibility by modifying the surface charges, surface morphology, and surface properties of the material. Coating methods based on polymer coatings, carbon-based coatings, and drug-functional coatings can regulate the surface properties, and also serve as an effective barrier to the interaction of metallic biomaterial surfaces with biomolecules, which can be used to improve corrosion resistance and stability, as well as improve their biocompatibility. Biocompatibility serves as the most fundamental property of cardiovascular stents, and maintaining the excellent and stable biocompatibility of cardiovascular stent surfaces is a current research bottleneck. Few reviews have been published on metallic biomaterials as cardiovascular stents and their surface treatments. For the purpose of advancing research on cardiovascular stents, common metal biomaterials, surface treatment methods, and coating methods to improve biocompatibility and comprehensive properties of the materials are described in this review. Finally, we suggest future directions for stent development, including continuously improving the durability and stability of permanent stents, accelerating the development of biodegradable stents, and strengthening feedback to improve the safety and reliability of cardiovascular stents.

Restoring endothelial function: shedding light on cardiovascular stent development

Complete endothelialization is highly important for maintaining long-term patency and avoiding subsequent complications in implanting cardiovascular stents. It not only refers to endothelial cells (ECs) fully covering the inserted stents, but also includes the newly formed endothelium, which could exert physiological functions, such as anti-thrombosis and anti-stenosis. Clinical outcomes have indicated that endothelial dysfunction, especially the insufficiency of antithrombotic and barrier functions, is responsible for stent failure. Learning from vascular pathophysiology, endothelial dysfunction on stents is closely linked to the microenvironment of ECs. Evidence points to inflammatory responses, oxidative stress, altered hemodynamic shear stress, and impaired endothelial barrier affecting the normal growth of ECs, which are the four major causes of endothelial dysfunction. The related molecular mechanisms and efforts dedicated to improving the endothelial function are emphasized in this review. From the perspective of endothelial function, the design principles, advantages, and disadvantages behind current stents are introduced to enlighten the development of new-generation stents, aiming to offer new alternatives for restoring endothelial function.

Vascular smooth muscle cells in intimal hyperplasia, an update

Arterial occlusive disease is the leading cause of death in Western countries. Core contemporary therapies for this disease include angioplasties, stents, endarterectomies and bypass surgery. However, these treatments suffer from high failure rates due to re-occlusive vascular wall adaptations and restenosis. Restenosis following vascular surgery is largely due to intimal hyperplasia. Intimal hyperplasia develops in response to vessel injury, leading to inflammation, vascular smooth muscle cells dedifferentiation, migration, proliferation and secretion of extra-cellular matrix into the vessel's innermost layer or intima. In this review, we describe the current state of knowledge on the origin and mechanisms underlying the dysregulated proliferation of vascular smooth muscle cells in intimal hyperplasia, and we present the new avenues of research targeting VSMC phenotype and proliferation.

Drug-loaded balloon with built-in NIR controlled tip-separable microneedles for long-effective arteriosclerosis treatment

Drug-eluting balloon (DEB) angioplasty has emerged as an effective treatment for cardiovascular and cerebrovascular diseases. However, distal embolism and late lumen restenosis could be caused by drug loss during DEB handling and rapid drug metabolization. Here, a drug-loaded balloon equipped with tip-separable microneedles on the balloon surface (MNDLB) was developed. Inbuilt near-infrared (NIR) ring laser inside the catheter inner shaft was introduced to activate the biodegradable microneedle tips for the first time. The drug-loaded tips thus could be embedded in the vasculature and then released antiproliferative drug - paclitaxel slowly via polymer degradation for more than half a year. A significant increase in drug delivery efficiency and superior therapeutic effectiveness compared with the standard DEB were demonstrated using an atherosclerosis rabbit model.

The Role of the VEGF Family in Atherosclerosis Development and Its Potential as Treatment Targets

The vascular endothelial growth factor (VEGF) family, the crucial regulator of angiogenesis, lymphangiogenesis, lipid metabolism and inflammation, is involved in the development of atherosclerosis and further CVDs (cardiovascular diseases). This review discusses the general regulation and functions of VEGFs, their role in lipid metabolism and atherosclerosis development and progression. These functions present the great potential of applying the VEGF family as a target in the treatment of atherosclerosis and related CVDs. In addition, we discuss several modern anti-atherosclerosis VEGFs-targeted experimental procedures, drugs and natural compounds, which could significantly improve the efficiency of atherosclerosis and related CVDs' treatment.