[Silver Ion Decreases Foreign Body Reaction and Venous Neointimal Hyperplasia through the Inhibition of Interleukin-33 Expression].

Introduction: Vascular prosthetic grafts are widely used in vascular surgery; however, graft infection remains a major concern. Silver-coated vascular grafts have demonstrated anti-infection properties in clinical settings; however, whether the silver irons influence foreign body reaction or neointimal hyperplasia remains unclear.

Methods: Sodium alginate and hyaluronic acid (SA/HA) hydrogel patches loaded with rhodamine, with or without silver, were fabricated.

Three-dimensional bioprinting of artificial blood vessel: Process, bioinks, and challenges.

The coronary artery bypass grafting is a main treatment for restoring the blood supply to the ischemic site by bypassing the narrow part, thereby improving the heart function of the patients. Autologous blood vessels are preferred in coronary artery bypass grafting, but their availability is often limited by due to the underlying disease. Thus, tissue-engineered vascular grafts that are devoid of thrombosis and have mechanical properties comparable to those of natural vessels are urgently required for clinical applications.

Deoxygenative Radical Boration of Inert Amides via a Combination of Relay and Cooperative Catalysis.

Invited for the cover of this issue is the group of Prof. Xiaoming Wang at the Shanghai Institute of Organic Chemistry and Hangzhou Institute for Advanced Study, University of the Chinese Academy of Sciences. The image depicts a combination of relay and cooperative catalysis with a triple iridium-photoredox-organocatalysis system to achieve an unprecedented reductive boration of amides.

Deoxygenative Radical Boration of Inert Amides via a Combination of Relay and Cooperative Catalysis.

One of the most challenging tasks in organic synthesis is to develop novel methodologies for rapid construction of complex molecules starting from easily available yet inert raw materials. In this context, multi-catalysis strategies have attracted great attention in the discovery of new reactivity profiles that may allow access to many difficult or unattainable transformations. So far the deoxygenative functionalization of ubiquitous amides is usually achieved by nucleophilic attack on the imine or iminium ion intermediate formed via activation of the C=O bond, and these functionalization reagents were often confined to C-based nucleophiles, which largely limited the diversity of the resultant amines.

Wood-Derived Vascular Patches Loaded With Rapamycin Inhibit Neointimal Hyperplasia.

Patches are commonly used to close blood vessels after vascular surgery. Most currently used materials are either prosthetics or animal-derived; although natural materials, such as a leaf, can be used as a patch, healing of these natural materials is not optimal; rhodamine and rapamycin have been used to show that coating patches with drugs allow drug delivery to inhibit neointimal hyperplasia that may improve patch healing. Wood is abundant, and its stiffness can be reduced with processing; however, whether wood can be used as a vascular patch is not established.

ADAM17: A novel treatment target for aneurysms.

Purpose: The mechanisms underlying abdominal aortic aneurysms (AAAs) are still not fully understood, previous researches showed ADAM17 is increased in aneurysm. We hypothesized that inhibiting ADAM17 can decrease AAA formation and progression.

Materials And Methods: Aneurysm models were established in mouses and rats by aortic adventitial CaCl incubation and aortic pericardial patch angioplasty respectively.

The application of tissue-engineered fish swim bladder vascular graft.

Small diameter (< 6 mm) prosthetic vascular grafts continue to show very low long-term patency, but bioengineered vascular grafts show promising results in preclinical experiments. To assess a new scaffold source, we tested the use of decellularized fish swim bladder as a vascular patch and tube in rats. Fresh goldfish (Carassius auratus) swim bladder was decellularized, coated with rapamycin and then formed into patches or tubes for implantation in vivo.

Hydrogel-coated needles prevent puncture site bleeding in arteriovenous fistula and arteriovenous grafts in rats.

Introduction: Imperfect hemostasis after arteriovenous fistula (AVF) and arteriovenous graft (AVG) cannulation can cause a hematoma or pseudoaneurysm and leads to poor satisfaction. We hypothesized that a hydrogel-coated needle would effectively and rapidly stop bleeding after vascular cannulation in a rat AVF and AVG model.

Method: A hydrogel comprised of sodium alginate (SA), hyaluronic acid (HA), and calcium carbonate was coated onto the surface of suture needles using a rotating system.

Programmed death-1 mediates venous neointimal hyperplasia in humans and rats.

Venous neointimal hyperplasia can be a problem after vein interventions. We hypothesized that inhibiting programmed death-1 (PD-1) can decrease venous neointimal hyperplasia in a rat inferior vena cava (IVC) patch venoplasty model. The rats were divided into four groups: the control group was only decellularized without other special treatment; the PD-1 group was injected with a single dose of humanized PD-1 antibody (4 mg/kg); the PD-1 antibody coated patches group; the BMS-1 (a PD-1 small molecular inhibitor) coated patches group (PD-1 inhibitor-1).

Advances in coatings on magnesium alloys for cardiovascular stents - A review.

Magnesium (Mg) and its alloys, as potential biodegradable materials, have drawn wide attention in the cardiovascular stent field because of their appropriate mechanical properties and biocompatibility. Nevertheless, the occurrence of thrombosis, inflammation, and restenosis of implanted Mg alloy stents caused by their poor corrosion resistance and insufficient endothelialization restrains their anticipated clinical applications. Numerous surface treatment tactics have mainly striven to modify the Mg alloy for inhibiting its degradation rate and enduing it with biological functionality.

A novel intramural TGF β 1 hydrogel delivery method to decrease murine abdominal aortic aneurysm and rat aortic pseudoaneurysm formation and progression.

Objectives: Aneurysms are generally the result of dilation of all 3 layers of the vessel wall, and pseudoaneurysms are the result of localized extravasation of blood that is contained by surrounding tissue. Since there is still no recommended protocol to decrease aneurysm formation and progression, we hypothesised that intramural delivery of TGF β1 hydrogel can decrease aneurysm and pseudoaneurysm formation and progression.

Materials: Male C57BL/6 J mice (12-14 wk), SD rats (200 g) and pig abdominal aortas were used, and hydrogels were fabricated by the interaction of sodium alginate (SA), hyaluronic acid (HA) and CaCO.

Enhancing biocompatibility and corrosion resistance of biodegradable Mg-Zn-Y-Nd alloy by preparing PDA/HA coating for potential application of cardiovascular biomaterials.

In this paper the poly-dopamine (PDA)/hyaluronic acid (HA) coatings with different HA molecular weight (MW, 4 × 10, 1 × 10, 5 × 10 and 1 × 10 Da) were prepared onto the NaOH passivated Mg-Zn-Y-Nd alloy aiming at potential application of cardiovascular implants. The characterization of weight loss, polarization curves and surface morphology indicated that the coatings with HA MW of 1 × 10 (PDA/HA-2) and 1 × 10 Da (PDA/HA-4) significantly enhanced the corrosion resistance of Mg-Zn-Y-Nd. In vitro biological test also suggested better hemocompatibility, pro-endothelialization, anti-hyperplasia and anti-inflammation functions of the PDA/HA-2- and PDA/HA-4-coated Mg-Zn-Y-Nd alloy.

Tailoring of cardiovascular stent material surface by immobilizing exosomes for better pro-endothelialization function.

Stent intervention as available method in clinic has been widely applied for cardiovascular disease treatment for decades. However, the restenosis caused by late thrombosis and hyperplasia still limits the stents long-term application, and the essential cause is usually recognized as endothelial functionalization insufficiency of the stent material surface. Here, we address this limitation by developing a pro-endothelial-functionalization surface that immobilized a natural factors-loaded nanoparticle, exosome, onto the poly-dopamine (PDA) coated materials via electrostatic binding.

An Injectable Nanocomposite Hydrogel for Potential Application of Vascularization and Tissue Repair.

In this contribution, an injectable hydrogel was developed with chitosan, gelatin, β-glycerphosphate and Arg-Gly-Asp (RGD) peptide: this hydrogel is liquid in room temperature and rapidly gels at 37 °C; RGD peptide promises better growth microenvironment for various cells, especially endothelial cells (EC), smooth muscle cells (SMC) and mesenchymal stem cells (MSC). Both stromal cell-derived factor-1 (SDF-1) nanoparticle and vascular endothelial growth factor (VEGF) nanoparticles were loaded in the injectable hydrogel to simulate the natural nanoparticles in the extracellular matrix (ECM) to promote angiogenesis. In vitro EC/SMC and MSC/SMC co-culture experiment indicated that the nanocomposite hydrogel accelerated constructing embryonic form of blood vessels, and chick embryo chorioallantoic membrane model demonstrated its ability of improving cells migration and blood vessel regeneration.

Effects of degradation products of biomedical magnesium alloys on nitric oxide release from vascular endothelial cells.

Nitric oxide (NO) released by vascular endothelial cells (VECs), as a functional factor and signal pathway molecule, plays an important role in regulating vasodilation, inhibiting thrombosis, proliferation and inflammation. Therefore, numerous researches have reported the relationship between the NO level in VECs and the cardiovascular biomaterials' structure/functions. In recent years, biomedical magnesium (Mg) alloys have been widely studied and rapidly developed in the cardiovascular stent field for their biodegradable absorption property.

An injectable scaffold based on temperature-responsive hydrogel and factor-loaded nanoparticles for application in vascularization in tissue engineering.

Controlled release of functional factors contributes to target migration of therapeutic cells and plays a crucial role in the in situ vascularization of tissue repair and regeneration. A biomedical application requires the selective release of multiple factors which will guide the synergy of the cells. Here, we developed an injectable system based on a temperature-responsive hydrogel and stromal cell-derived factor-1 (SDF-1)/vascular endothelial growth factor (VEGF) loaded into two types of nanoparticles to induce migration and rapid proliferation of mesenchymal stem cells (MSCs) and endothelial cells (ECs) via selective SDF-1/VEGF release.

Preparation of a biomimetic ECM surface on cardiovascular biomaterials via a novel layer-by-layer decellularization for better biocompatibility.

Endothelial extracellular matrix (EC-ECM) modification by decellularization is generally recognized as an effective method for cardiovascular biomaterials to enhance their biocompatibility. However, the now available EC-ECM was mainly secreted by the in vitro cultured endothelial cells which lacked a physiological growth environment in vivo, such as blood flow shear stress (BFSS) acting, thus had a serious defect of biocompatibility. Our previous work markedly improved the biocompatibility of the EC-ECM modified materials by simulating the BFSS acting to control the endothelial cells with hyaluronic acid (HA) micro-pattern.

Mechanical Property of TiO₂ Nano-Tubes Surface Based on the Investigation of Residual Stress, Tensile Force and Fluid Flow Shear Stress: For Potential Application of Cardiovascular Devices.

The TiO2 nanotube has been anticipated for potential application for cardiovascular implanted devices for its excellent drug loading/release function and biocompatibility. However, its mechanical behavior has rarely been studied as the cardiovascular devices. The tube length is a crucial factor which not only decides the drug loading ability but also influences the devices' mechanical behavior.

Platelet Adhesion and Activation on Chiral Surfaces: The Influence of Protein Adsorption.

Adsorbed proteins and their conformational change on blood-contacting biomaterials will determine their final hemocompatibility. It has frequently been reported that surface chirality of biomaterials may highly influence their protein adsorption behavior. Here, lysine and tartaric acid with different chirality were immobilized onto TiO films respectively, and the influence of surface chirality on protein adsorption, platelet adhesion, and activation was also investigated.

Constructing bio-layer of heparin and type IV collagen on titanium surface for improving its endothelialization and blood compatibility.

The modification of cardiovascular stent surface for a better micro-environment has gradually changed to multi-molecule, multi-functional designation. In this study, heparin (Hep) and type IV collagen (IVCol) were used as the functional molecule to construct a bifunctional micro-environment of anticoagulation and promoting endothelialization on titanium (Ti). The surface characterization results (AFM, Alcian Blue 8GX Staining and fluorescence staining of IVCol) indicated that the bio-layer of Hep and IVCol were successfully fabricated on the Ti surface through electrostatic self-assembly.

The endothelialization and hemocompatibility of the functional multilayer on titanium surface constructed with type IV collagen and heparin.

The type IV collagen/heparin (IVCol/Hep) multilayer was developed on amino-silanized titanium (Ti) surface layer by layer self-assembly. Ti, TiOH, TiOHA and TiOHA(HC)3H were characterized by Fourier transform infrared spectroscopy (FTIR), water contact angle measurements and scanning electron microscopy (SEM), respectively. Alcian Blue 8GX staining and immunofluorescence staining were used to characterize the heparin (Hep) and type IV collagen (IVCol), respectively.

Surface modification of implanted cardiovascular metal stents: from antithrombosis and antirestenosis to endothelialization.

Driven by the complications occurring with bare metal stents and drug-eluting stents, concerns have been raised over strategies for long-term safety, with respect to preventing or inhibiting stent thrombosis, restenosis, and in-stent restenosis in particularly. Surface modification is very important in constructing a buffer layer at the interface of the organic and inorganic materials and in ultimately obtaining long-term biocompatibility. In this review, we summarize the developments in surface modification of implanted cardiovascular metal stents.