Mechanisms of smooth muscle cell proliferation and endothelial regeneration after vascular injury and stenting: approach to therapy

A Critical Review of Biodegradable Zinc Alloys toward Clinical Applications

Biodegradable zinc (Zn) alloys stand out as promising contenders for biomedical applications due to their favorable mechanical properties and appropriate degradation rates, offering the potential to mitigate the risks and expenses associated with secondary surgeries. While current research predominantly centers on the in vitro examination of Zn alloys, notable disparities often emerge between in vivo and in vitro findings. Consequently, conducting in vivo investigations on Zn alloys holds paramount significance in advancing their clinical application. Different element compositions and processing methods decide the mechanical properties and biological performance of Zn alloys, thus affecting their suitability for specific medical applications. This paper presents a comprehensive overview of recent strides in the development of biodegradable Zn alloys, with a focus on key aspects such as mechanical properties, toxicity, animal experiments, biological properties, and molecular mechanisms. By summarizing these advancements, the paper aims to broaden the scope of research directions and enhance the understanding of the clinical applications of biodegradable Zn alloys.

Optimizing the Biocompatibility of PLLA Stent Materials: Strategy with Biomimetic Coating

Background

Poly-L-lactic acid (PLLA) stents have broad application prospects in the treatment of cardiovascular diseases due to their excellent mechanical properties and biodegradability. However, foreign body reactions caused by stent implantation remain a bottleneck that limits the clinical application of PLLA stents. To solve this problem, the biocompatibility of PLLA stents must be urgently improved. Albumin, the most abundant inert protein in the blood, possesses the ability to modify the surface of biomaterials, mitigating foreign body reactions-a phenomenon described as the "stealth effect". In recent years, a strategy based on albumin camouflage has become a focal point in nanomedicine delivery and tissue engineering research. Therefore, albumin surface modification is anticipated to enhance the surface biological characteristics required for vascular stents. However, the therapeutic applicability of this modification has not been fully explored.

Methods

Herein, a bionic albumin (PDA-BSA) coating was constructed on the surface of PLLA by a mussel-inspired surface modification technique using polydopamine (PDA) to enhance the immobilization of bovine serum albumin (BSA).

Results

Surface characterization revealed that the PDA-BSA coating was successfully constructed on the surface of PLLA materials, significantly improving their hydrophilicity. Furthermore, in vivo and in vitro studies demonstrated that this PDA-BSA coating enhanced the anticoagulant properties and pro-endothelialization effects of the PLLA material surface while inhibiting the inflammatory response and neointimal hyperplasia at the implantation site.

Conclusion

These findings suggest that the PDA-BSA coating provides a multifunctional biointerface for PLLA stent materials, markedly improving their biocompatibility. Further research into the diverse applications of this coating in vascular implants is warranted.

Role of C/EBP Homologous Protein in Vascular Stenosis After Carotid Artery Injury

The study aims to explore the fluctuating expression of C/EBP Homologous Protein (CHOP) following rat carotid artery injury and its central role in vascular stenosis. Using in vivo rat carotid artery injury models and in vitro ischemia and hypoxia cell models employing human aortic endothelial cells (HAECs) and vascular smooth muscle cells (T/G HA-VSMCs), a comprehensive investigative framework was established. Histological analysis confirmed intimal hyperplasia in rat models. CHOP expression in vascular tissues was assessed using Western blot and immunohistochemical staining, and its presence in HAECs and T/G HA-VSMCs was determined through RT-PCR and Western blot. The study evaluated HAEC apoptosis, inflammatory cytokine secretion, cell proliferation, and T/G HA-VSMCs migration through Western blot, ELISA, CCK8, and Transwell migration assays. The rat carotid artery injury model revealed substantial fibrous plaque formation and vascular stenosis, resulting in an increased intimal area and plaque-to-lumen area ratio. Notably, CHOP is markedly elevated in vessels of the carotid artery injury model compared to normal vessels. Atorvastatin effectively mitigated vascular stenosis and suppresses CHOP protein expression. In HAECs, ischemia and hypoxia-induced CHOP upregulation, along with heightened TNFα, IL-6, caspase3, and caspase8 levels, while reducing cell proliferation. Atorvastatin demonstrated a dose-dependent suppression of CHOP expression in HAECs. Downregulation of CHOP or atorvastatin treatment led to reduced IL-6 and TNFα secretion, coupled with augmented cell proliferation. Similarly, ischemia and hypoxia conditions increased CHOP expression in T/G HA-VSMCs, which was concentration-dependently inhibited by atorvastatin. Furthermore, significantly increased MMP-9 and MMP-2 concentrations in the cell culture supernatant correlated with enhanced T/G HA-VSMCs migration. However, interventions targeting CHOP downregulation and atorvastatin usage curtailed MMP-9 and MMP-2 secretion and suppressed cell migration. In conclusion, CHOP plays a crucial role in endothelial injury, proliferation, and VSMCs migration during carotid artery injury, serving as a pivotal regulator in post-injury fibrous plaque formation and vascular remodeling. Statins emerge as protectors of endothelial cells, restraining VSMCs migration by modulating CHOP expression.

Endothelium-Mimicking Bilayer Vascular Grafts with Dual-Releasing of NO/H2S for Anti-Inflammation and Anticalcification

Vascular complications caused by diabetes impair the activities of endothelial nitric oxide synthase (eNOS) and cystathionine γ-lyase (CSE), resulting in decreased physiological levels of nitric oxide (NO) and hydrogen sulfide (H2S). The low bioavailability of NO and H2S hinders the endothelialization of vascular grafts. In this study, endothelium-mimicking bilayer vascular grafts were designed with spatiotemporally controlled dual releases of NO and H2S for in situ endothelialization and angiogenesis. Keratin-based H2S donor was synthesized and electrospun with poly(l-lactide-co-ε-caprolactone) (PLCL) as the outer layer of the graft to release H2S. Hyaluronic acid, one of the major glycosaminoglycans in endothelial glycocalyx, was complexed with Cu ions as the inner layer to mimic glutathione peroxidase (GPx) and maintain long-term physiological NO flux. The synergistic effects of NO and H2S of bilayer grafts selectively promoted the regeneration and migration of human umbilical vascular endothelial cells (HUVECs), while inhibiting the overproliferation of human umbilical artery smooth muscle cells (HUASMCs). Bilayer grafts could effectively prevent vascular calcification, reduce inflammation, and alleviate endothelial dysfunction. The in vivo study in a rat abdominal aorta replacement model for 1 month showed that the graft had a good patency rate and had potential for vascular remodeling in situ.

In vitro biological responses of plasma nanocoatings for coronary stent applications

In-stent restenosis and thrombosis remain to be long-term challenges in coronary stenting procedures. The objective of this study was to evaluate the in vitro biological responses of trimethylsilane (TMS) plasma nanocoatings modified with NH3 /O2 (2:1 molar ratio) plasma post-treatment (TMS + NH3 /O2 nanocoatings) on cobalt chromium (CoCr) alloy L605 coupons, L605 stents, and 316L stainless steel (SS) stents. Surface properties of the plasma nanocoatings with up to 2-year aging time were characterized by wettability assessment and x-ray photoelectron spectroscopy (XPS). It was found that TMS + NH3 /O2 nanocoatings had a surface composition of 41.21 ± 1.06 at% oxygen, 31.90 ± 1.08 at% silicon, and 24.12 ± 1.7 at% carbon, and very small but essential amount of 2.77 ± 0.18 at% nitrogen. Surface chemical stability of the plasma coatings was noted with persistent O/Si atomic ratio of 1.292-1.413 and N/Si atomic ratio of ~0.087 through 2 years. The in vitro biological responses of plasma nanocoatings were studied by evaluating the cell proliferation and migration of porcine coronary artery endothelial cells (PCAECs) and smooth muscle cells (PCASMCs). 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium (MTT) assay results revealed that, after 7-day incubation, TMS + NH3 /O2 nanocoatings maintained a similar level of PCAEC proliferation while showing a decrease in the viability of PCASMCs by 73 ± 19% as compared with uncoated L605 surfaces. Cell co-culture of PCAECs and PCASMCs results showed that, the cell ratio of PCAEC/PCASMC on TMS + NH3 /O2 nanocoating surfaces was 1.5-fold higher than that on uncoated L605 surfaces, indicating enhanced selectivity for promoting PCAEC growth. Migration test showed comparable PCAEC migration distance for uncoated L605 and TMS + NH3 /O2 nanocoatings. In contrast, PCASMC migration distance was reduced nearly 8.5-fold on TMS + NH3 /O2 nanocoating surfaces as compared to the uncoated L605 surfaces. Platelet adhesion test using porcine whole blood showed lower adhered platelets distribution (by 70 ± 16%), reduced clotting attachment (by 54 ± 12%), and less platelet activation on TMS + NH3 /O2 nanocoating surfaces as compared with the uncoated L605 controls. It was further found that, under shear stress conditions of simulated blood flow, TMS + NH3 /O2 nanocoating significantly inhibited platelet adhesion compared to the uncoated 316L SS stents and TMS nanocoated 316L SS stents. These results indicate that TMS + NH3 /O2 nanocoatings are very promising in preventing both restenosis and thrombosis for coronary stent applications.

Bergamot Polyphenolic Extract Combined with Albedo and Pulp Fibres Counteracts Changes in Gut Microbiota Associated with High-Fat Diet: Implications for Lipoprotein Size Re-Arrangement

Evidence exists that the gut microbiota contributes to the alterations of lipid metabolism associated with high-fat diet (HFD). Moreover, the gut microbiota has been found to modulate the metabolism and absorption of dietary lipids, thereby affecting the formation of lipoproteins occurring at the intestinal level as well as systemically, though the pathophysiological implication of altered microbiota composition in HFD and its role in the development of atherosclerotic vascular disease (ATVD) remain to be better clarified. Recently, evidence has been collected indicating that supplementation with natural polyphenols and fibres accounts for an improvement of HFD-associated intestinal dysbiosis, thereby leading to improved lipidaemic profile. This study aimed to investigate the protective effect of a bergamot polyphenolic extract (BPE) containing 48% polyphenols enriched with albedo and pulp-derived micronized fibres (BMF) in the gut microbiota of HFD-induced dyslipidaemia. In particular, rats that received an HFD over a period of four consecutive weeks showed a significant increase in plasma cholesterol, triglycerides and plasma glucose compared to a normal-fat diet (NFD) group. This effect was accompanied by body weight increase and alteration of lipoprotein size and concentration, followed by high levels of MDA, a biomarker of lipid peroxidation. Treatment with a combination of BPE plus BMF (50/50%) resulted in a significant reduction in alterations of the metabolic parameters found in HFD-fed rats, an effect associated with increased size of lipoproteins. Furthermore, the effect of BPE plus BMF treatment on metabolic balance and lipoprotein size re-arrangement was associated with reduced gut-derived lipopolysaccharide (LPS) levels, an effect subsequent to improved gut microbiota as expressed by modulation of the Gram-negative bacteria Proteobacteria, as well as Firmicutes and Bacteroidetes. This study suggests that nutraceutical supplementation of HFD-fed rats with BPE and BMP or with their combination product leads to restored gut microbiota, an effect associated with lipoprotein size re-arrangement and better lipidaemic and metabolic profiles.

Multistage Anticoagulant Surfaces: A Synergistic Combination of Protein Resistance, Fibrinolysis, and Endothelialization

Anticoagulant surface modification of blood-contacting materials has been shown to be effective in preventing thrombosis and reducing the dose of anticoagulant drugs that patients take. However, commercially available anticoagulant coatings, that is, both bioinert and bioactive coatings, are typically based on a single anticoagulation strategy. This puts the anticoagulation function of the coating at risk of failure during long-term use. Considering the several pathways of the human coagulation system, the synergy of multiple anticoagulation theories may provide separate, targeted effects at different stages of thrombosis. Based on this presumption, in this work, negatively charged poly(sodium p-styrenesulfonate-co-oligo(ethylene glycol) methyl ether methacrylate) and positively charged poly(lysine-co-1-adamantan-1-ylmethyl methacrylate) were synthesized to construct matrix layers on the substrate by electrostatic layer-by-layer self-assembly (LBL). Amino-functionalized β-cyclodextrin (β-CD-PEI) was subsequently immobilized on the surface by host-guest interactions, and heparin was grafted. By adjusting the content of poly(oligo(ethylene glycol) methyl ether methacrylate) (POEGMA), the interactions between modified surfaces and plasma proteins/cells were regulated. This multistage anticoagulant surface exhibits inertness at the initial stage of implantation, resisting nonspecific protein adsorption (POEGMA). When coagulation reactions occur, heparin exerts its active anticoagulant function in a timely manner, blocking the pathway of thrombosis. If thrombus formation is inevitable, lysine can play a fibrinolytic role in dissolving fibrin clots. Finally, during implantation, endothelial cells continue to adhere and proliferate on the surface, forming an endothelial layer, which meets the blood compatibility requirements. This method provides a new approach to construct a multistage anticoagulant surface for blood-contacting materials.

Safety and effect of pipeline flex embolization device for complex unruptured intracranial aneurysms

To investigate the safety and short-term effect of Pipeline Flex devices in the treatment of complex unruptured intracranial aneurysms, a retrospective study was performed for patients with complex unruptured intracranial aneurysms who were treated with the Pipeline Flex embolization device (PED Flex device) combined with or without coiling. The clinical, endovascular, and follow-up data were analyzed. One hundred and thirty-one patients with 159 complex unruptured cerebral aneurysms were treated with the PED Flex device, with 144 Flex devices deployed. Periprocedural complications occurred in four patients, resulting in the complication rate of 3.1%, including ischemic complications in three patients (2.3%) and hemorrhagic complication in one (0.8%). At discharge, the mRS was 0 in 101 (77.1%) patients, 1 in 25 (19.1%), 2 in four (3.1%), and 4 in one (0.8%), with the good prognosis rate (mRS 0-2) of 99.2%. Clinical follow-up was carried out in 87 (66.4%) patients 3-42 months after the procedure, with the mRS of 0 in 78 (89.7%), 1 in five (5.7%), 2 in three (3.4%), and 4 in one (1.1%). No significant (P = 0.16) difference existed in the mRS at discharge compared with that at clinical follow-up. Angiographic follow-up was performed in 61 (46.7%) patients with 80 (50.3%) aneurysms at 3-40 months, with the OKM grade of D in 57 (71.3%) aneurysms, C in eight (10%), and B in 15 (18.8%). Asymptomatic instent stenosis occurred in four patients (6.6%). In conclusion: The treatment of complex intracranial aneurysms with the Pipeline Flex embolization device may be safe and effective, with a high complete occlusion rate, a decreased complication rate, and a good prognosis rate at medium follow-up.

High shear stress attenuated arterial neointimal hyperplasia accompanied by changes in yes-associated protein/jun N-terminal kinase/vascular cell adhesion protein 1 expression

BACKGROUND AND OBJECTIVES

Abnormal neointimal hyperplasia (NIH) is known as the predominant mechanism in the pathogenesis of arterial restenosis after balloon angioplasty. Low shear stress (SS) is known to augment balloon injury-induced NIH. The aim of this study is to study the effect and mechanisms of an increase of shear stress caused by arteriovenous fistula could alleviate arterial NIH caused by balloon injury.

METHODS AND RESULTS

Eighteen male rabbits were randomly divided into three groups: BI-the rabbits received a balloon injury to right common carotid artery (CCA). BI+AVF-the rabbits received a balloon injury to right CCA and a carotid-jugular AVF. Control-the animals received no surgery. After 21 days, CCA samples were harvested for histological staining, immunohistochemistry, and western blot analysis. The luminal shear stress of the BI+AVF group increased from 13.8 ± 1.0 dyn/cm² before surgery to 30.9 ± 1.7 dyn/cm² right after surgery (p < 0.01). This value was higher than that of the BI or Control groups at any timepoint. The neointimal area and neointima/media area ratio in the BI+AVF group were significantly lower than those in the BI group. In the BI group, the cellular proliferation, the protein levels of yes-associated protein (YAP), connective tissue growth factor (CTGF), phospho-c-Jun N-terminal kinase (pJNK), and vascular cell adhesion protein 1 (VCAM1) increased, whereas the protein levels of SMCs specific genes decreased. In the BI+AVF group, the opposite effect was observed as cellular proliferation and the protein levels of YAP, CTGF, pJNK, and VCAM1 decreased, the protein levels of SMCs specific genes increased.

CONCLUSION

The arteriovenous fistula alleviated the balloon injury-induced arterial NIH. It elevated the luminal shear stress and inhibited SMCs phenotypic modulation to the synthetic state, as well as suppressing the over-activation of YAP, JNK, and VCAM1.

Iron corroded granules inhibiting vascular smooth muscle cell proliferation

In-stent restenosis after interventional therapy remains a severe clinical complication. Current evidence indicates that neointimal hyperplasia induced by vascular smooth muscle cell (VSMC) proliferation is a major cause of restenosis. Thus, inhibiting VSMC proliferation is critical for preventing in-stent restenosis. The incidence of restenosis was reduced in nitrided iron-based stents (hereafter referred to as iron stents). We hypothesized that the corroded granules produced by the iron stent would prevent in-stent restenosis by inhibiting VSMC proliferation. To verify this hypothesis, we introduced a dynamic circulation device to analyze the components of corroded granules. To investigate the effects of corroded granules on VSMC proliferation, we implanted the corroded iron stent into the artery of the atherosclerotic artery stenosis model. Moreover, we explored the mechanism underlying the inhibition of VSMC proliferation by iron corroded granules. The results indicated that iron stent produced the corroded granules after implantation, and the main component of the corrosion granules was iron oxide. Remarkably, the corroded granules reduced the neointimal hyperplasia in an atherosclerotic artery stenosis model, and iron corroded granules decreased the neointimal hyperplasia by inhibiting VSMC proliferation. In addition, we revealed that corroded granules reduced VSMC proliferation by activating autophagy through the AMPK/mTOR signaling pathway. Importantly, safety of iron corroded granules was evaluated and proved to be satisfactory hemocompatibility in rabbit model. Overall, the role of corroded granules in restenosis prevention was described for the first time. This finding highlighted the implication of corroded granules produced by iron stent in inhibiting VSMC proliferation, pointing to a new direction to prevent in-stent restenosis.

A Biocompatibility Study of Plasma Nanocoatings onto Cobalt Chromium L605 Alloy for Cardiovascular Stent Applications

The objective of this study was to evaluate the biocompatibility of trimethylsilane (TMS) plasma nanocoatings modified with NH₃/O₂ (2:1 molar ratio) plasma post-treatment onto cobalt chromium (CoCr) L605 alloy coupons and stents for cardiovascular stent applications. Biocompatibility of plasma nanocoatings was evaluated by coating adhesion, corrosion behavior, ion releasing, cytotoxicity, and cell proliferation. Surface chemistry and wettability were studied to understand effects of surface properties on biocompatibility. Results show that NH₃/O₂ post-treated TMS plasma nanocoatings are hydrophilic with water contact angle of 48.5° and have a typical surface composition of O (39.39 at.%), Si (31.92 at.%), C (24.12 at.%), and N (2.77 at.%). The plasma nanocoatings were conformal to substrate surface topography and had excellent adhesion to the alloy substrates, as assessed by tape test (ASTM D3359), and showed no cracking or peeling off L605 stent surfaces after dilation. The plasma nanocoatings also improve the corrosion resistance of CoCr L605 alloy by increasing corrosion potential and decreasing corrosion rates with no pitting corrosion and no mineral adsorption layer. Ion releasing test revealed that Co, Cr, and Ni ion concentrations were reduced by 64-79%, 67-69%, and 57-72%, respectively, in the plasma-nanocoated L605 samples as compared to uncoated L605 control samples. The plasma nanocoatings showed no sign of cytotoxicity from the test results according to ISO 10993-05 and 10993-12. Seven-day cell culture demonstrated that, in comparison with the uncoated L605 control surfaces, the plasma nanocoating surfaces showed 62 ± 7.3% decrease in porcine coronary artery smooth muscle cells (PCASMCs) density and had comparable density of porcine coronary artery endothelial cells (PCAECs). These results suggest that TMS plasma nanocoatings with NH₃/O₂ plasma post-treatment possess the desired biocompatibility for stent applications and support the hypothesis that nanocoated stents could be very effective for in-stent restenosis prevention.

IMP3 promotes re-endothelialization after arterial injury via increasing stability of VEGF mRNAhv

IMP3, an RNA‐binding protein (RBP) that participates in the process of post‐transcriptional modifications of mRNA transcripts, is capable of altering cellular functions, and in some cases, be involved in specific disease progression. We aimed to investigate whether IMP3 has the ability to regulate the functional properties of endothelial cells and re‐endothelialization in response to arterial injury. Wire injury was introduced to the right carotid arteries of wildtype C57/BL6 mice. As a result, IMPs’ expressions were up‐regulated in the induced arterial lesions, and IMP3 was the most up‐regulated RNA among other IMPs. We overexpressed IMP3 before the wire‐injured surgery using adeno‐associated virus AAV2‐IMP3. In vivo studies confirmed that IMP3 overexpression accelerated the progress of re‐endothelialization after arterial injury. In vitro, endothelial cells were transfected with either ad‐IMP3 or Si‐IMP3, cell functional studies showed that IMP3 could promote endothelial cell proliferation and migration, while reducing apoptosis. Mechanistic studies also revealed that IMP3 could enhance VEGF mRNA stability and therefore up‐regulate activities of VEGF/PI3K/Akt signalling pathway. Our data indicated that IMP3 promotes re‐endothelialization after arterial injury and regulates endothelial cell proliferation, migration and apoptosis via increasing stability of VEGF mRNA and activation of VEGF/PI3K/Akt signalling pathway.

Progerin-Induced Impairment in Wound Healing and Proliferation in Vascular Endothelial Cells

Progerin as a mutated isoform of lamin A protein was first known to induce premature atherosclerosis progression in patients with Hutchinson-Gilford progeria syndrome (HGPS), and its role in provoking an inflammatory response in vascular cells and accelerating cell senescence has been investigated recently. However, how progerin triggers endothelial dysfunction that often occurs at the early stage of atherosclerosis in a mechanical environment has not been studied intensively. Here, we generated a stable endothelial cell line that expressed progerin and examined its effects on endothelial wound repair under laminar flow. We found decreased wound healing rate in progerin-expressing ECs under higher shear stress compared with those under low shear. Furthermore, the decreased wound recovery could be due to reduced number of cells at late mitosis, suggesting potential interference by progerin with endothelial proliferation. These findings provided insights into how progerin affects endothelial mechanotransduction and may contribute to the disruption of endothelial integrity in HGPS vasculature, as we continue to examine the mechanistic effect of progerin in shear-induced endothelial functions.

Apolipoprotein J Attenuates Vascular Restenosis by Promoting Autophagy and Inhibiting the Proliferation and Migration of Vascular Smooth Muscle Cells

This research investigated the mechanism of CLU in vascular restenosis by regulating vascular smooth muscle cell (VSMC) proliferation and migration. Firstly, rat models of balloon injury (BI) were established, followed by the assessment of the injury to the common carotid artery. The effect of CLU on the intimal hyperplasia of BI rats was measured after the intervention in CLU, in addition to the evaluation of proliferation, migration, and autophagy of VSMCs. Moreover, the interaction between ATG and LC3 was analyzed, followed by validation of the role of autophagy in CLU's regulation on the proliferation and migration of VSMCs. It was found that CLU was highly expressed in BI rats. Altogether, our findings indicated that CLU was highly expressed in vascular restenosis, and CLU over-expression promoted the binding between ATG3 and LC3, thus facilitating VSMC autophagy and eventually attenuating intimal hyperplasia and vascular restenosis.

pH-Responsive Nanoparticles for Delivery of Paclitaxel to the Injury Site for Inhibiting Vascular Restenosis

A high incidence of restenosis has been reported at the site of inflammation following angioplasty and stent implantation. The anti-proliferative drug paclitaxel (PTX) could help to reduce inflammation and restenosis; however, it has poor water solubility and serious adverse side effects at high doses. Given the presence of metabolic acidosis at the site of inflammation, we hypothesized that nanoparticles that are responsive to low pH could precisely release the loaded drug at the target site. We successfully constructed pH-responsive poly(D, L-lactic-co-glycolic acid) (PLGA) nanoparticles loaded with PTX and NaHCO3 as a pH-sensitive therapeutic agent (PTX-NaHCO3-PLGA NPs). The NPs exhibited remarkable pH sensitivity and a good safety profile both in vitro in rat vascular smooth muscle cells and in vivo in Sprague Dawley rats after tail vein injection. In the rat model, the PTX-NaHCO3-PLGA NPs treatment group showed suppressed intimal proliferation following balloon-induced carotid artery injury compared with that of the saline-treated control. Overall, these results demonstrate that our newly developed pH-responsive nanodrug delivery platform has the potential to effectively inhibit restenosis.

Plasma Proteome Profiling of Patients With In-stent Restenosis by Tandem Mass Tag-Based Quantitative Proteomics Approach

Background

Despite the widespread application of new drug-eluting stents, a considerable portion of patients experience in-stent restenosis (ISR). To date, the pathophysiologic mechanisms of ISR remain poorly understood.

Methods

In this study, we collected plasma samples from ISR patients (n = 29) and non-ISR patients (n = 36) after drug-eluting stent implantation, as well as from healthy controls (HCs) (n = 32). Our goal was to investigate differences in plasma protein profiles using tandem mass tag (TMT) labeling coupled with liquid chromatography and tandem mass spectrometry. The proteomic data were validated by enzyme-linked immunosorbent assay (ELISA). Bioinformatic analyses were conducted to analyze potential pathways and protein-protein interaction (PPI) involved in ISR.

Results

A total of 1,696 proteins were identified, of which 278 differed in protein abundance between non-ISR and HCs, 497 between ISR and HCs, and 387 between ISR and non-ISR, respectively. Bioinformatic analyses, including Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) and PPI, further demonstrated that differentially abundant proteins between ISR and non-ISR are involved in several crucial biological processes and signaling pathways, such as focal adhesion, platelet activation, Rap1 signaling, regulation of actin cytoskeleton, and cholesterol metabolism. Among the identified differentially abundant proteins in ISR, 170 were increased in abundance relative to both non-ISR patients and HCs. Some of these proteins were identified to have critical functions for atherosclerosis development and might be involved in ISR pathology. Among these proteins, 3 proteins with increased abundance including fetuin-B, apolipoprotein C-III (APOC3), and cholesteryl ester transfer protein (CETP) were confirmed by ELISA.

Conclusions

This is the first study provided a comprehensive proteomic profile to understand ISR pathology, which may help identify early diagnostic biomarkers and therapeutic targets.

10-gingerol, a natural AMPK agonist, suppresses neointimal hyperplasia and inhibits vascular smooth muscle cells proliferation

Background: Abnormal proliferation of vascular smooth muscle cells (VSMCs) in the intimal region is a key event in the development of neointimal hyperplasia. 10-G, a bioactive compound found in ginger,...

Investigation into the role of Stmn2 in vascular smooth muscle phenotype transformation during vascular injury via RNA sequencing and experimental validation

This study examined the effects of Stmn2 on phenotype transformation of vascular smooth muscle in vascular injury via RNA sequencing and experimental validation. Total RNA was extracted for RNA sequencing after 1, 3 and 5 days of injury to screen the differentially expressed genes (DEGs). Western blot was used to detect the protein expression of Stmn2 and its associated targets. The morphological changes of carotid arteries in rats were examined by hematoxylin and eosin (H&E) staining. The expression of vascular smooth muscle cell (VSMC) phenotype markers smooth muscle alpha-actin (α-SMA), vimentin and OPN were detected by immunohistochemistry. DEGs were related to the extracellular matrix and other cell components outside the plasma membrane. They were associated with protein binding, cytoskeleton protein binding, signal receptor binding and other molecular functions, actin cytoskeleton regulation and other Kyoto Encyclopedia of Genes and Genomes pathways. Stmn2 was identified as the hub gene of actin cytoskeleton pathway and vascular disease, and its expression followed the trend of decreasing initially and increasing afterwards during the progress of vascular injury. Western blot assay showed that the expression of Stmn2 and Tubulin decreased immediately after vascular injury; Stmn2 overexpression significantly up-regulated the expression of osteopontin and α-SMA and vimentin in VSMCs. The results of morphology analysis and immunostaining also showed that Stmn2 overexpression promoted the intima thickening and enhanced the proliferating cell nuclear antigen expression in the injured vascular tissues. In conclusion, our results implied that Stmn2 may play a potential role in vascular injury, which may be associated with VSMC phenotype transformation. Further studies are warranted to determine detailed molecular mechanisms of Stmn2 in vascular injury.

Superficial Temporal Artery (STA)-Posterior Cerebral Artery (PCA) Bypass through Zygomatic Anterior Temporal Approach for Complex PCA Aneurysm: Technique Notes

BACKGROUND

Posterior cerebral artery (PCA) aneurysms are rare and the majority are giant, dissecting, or fusiform in morphology. Proximal occlusion of PCA without revascularization causes a high risk of ischemic complications. This study aimed to evaluate the safety and validity of using superficial temporal artery (STA)-posterior cerebral artery (PCA) Bypass through zygomatic anterior temporal approach in complex PCA aneurysms.

METHODS

Trapping or resecting of the aneurysms and reconstruction of the distal PCA through a zygomatic anterior temporal approach were performed in 6 patients from June 2017 to August 2020. Postoperative angiography was used to confirm the obliteration of the aneurysms and the patency of bypass artery. Neurologic function was assessed by the modified Rankin Scale.

RESULTS

Four male and 2 female patients with a mean age of 43.8 years (Range, 21-58 years) were assessed. Subarachnoid hemorrhage occurred in 5 patients, including 3 patients with Hunt-Hess grade IV, 2 patients with grade III, and 1 patient with grade I. All PCA aneurysms were treated with trapping or resecting of the aneurysms and revascularization of the distal PCA. Postoperatively, all aneurysms were eliminated and no new permanent neurological deficit was found. During the follow-up, Modified mRS of all patients were improved: There were 2 patients with mRS Score 0, 1 patient with mRS Score 1, 1 patient with mRS Score 3, and 2 patients with mRS Score 4. The long-term graft patency rate was 100%.

CONCLUSION

The STA-PCA bypass appears to be a safe and effective method for the treatment of complex PCA aneurysms requiring supplementing the blood flow in the area of the PCA. We established a surgical route, allowing the procedure to be done through the zygomatic anterior temporal approach. This approach provides adequate operative field exposure and reduces retraction of the temporal lobe.

The multiple roles of chemokines in the mechanisms of stent biocompatibility

While the advent of drug-eluting stents has been clinically effective in substantially reducing the rates of major stent-related adverse events compared with bare metal stents, vascular biological problems such as neointimal hyperplasia, delayed re-endothelialization, late stent thrombosis are not eliminated and, increasingly, neoatherosclerosis is the underlying mechanism for very late stent failure. Further understanding regarding the mechanisms underlying the biological responses to stent deployment is therefore required so that new and improved therapies can be developed. This review will discuss the accumulating evidence that the chemokines, small inflammatory proteins, play a role in each key biological process of stent biocompatibility. It will address the chemokine system in its specialized roles in regulating the multiple facets of vascular biocompatibility including neointimal hyperplasia, endothelial progenitor cell (EPC) mobilization and re-endothelialization after vascular injury, platelet activation and thrombosis, as well as neoatherosclerosis. The evidence in this review suggests that chemokine-targeting strategies may be effective in controlling the pathobiological processes that lead to stent failure. Preclinical studies provide evidence that inhibition of specific chemokines and/or broad-spectrum inhibition of the CC-chemokine class prevents neointimal hyperplasia, reduces thrombosis and suppresses the development of neoatherosclerosis. In contrast, however, to these apparent deleterious effects of chemokines on stent biocompatibility, the CXC chemokine, CXCL12, is essential for the mobilization and recruitment of EPCs that make important contributions to re-endothelialization post-stent deployment. This suggests that future chemokine inhibition strategies would need to be correctly targeted so that all key stent biocompatibility areas could be addressed, without compromising important adaptive biological responses.

The effects of a biodegradable Mg-based alloy on the function of VSMCs via immunoregulation of macrophages through Mg-induced responses

Background

Restenosis is one of the worst side effects of percutaneous coronary intervention (PCI) due to neointima formation resulting from the excessive proliferation and migration of vascular smooth muscle cells (VSMCs) and continuous inflammation. Biodegradable Mg-based alloy is a promising candidate material because of its good mechanical properties and biocompatibility, and biodegradation of cardiovascular stents. Although studies have shown reduced neointima formation after Mg-based CVS implantation in vivo, these findings were inconsistent with in vitro studies, demonstrating magnesium-mediated promotion of the proliferation and migration of VSMCs. Given the vital role of activated macrophage-driven inflammation in neointima formation, along with the well-demonstrated crosstalk between macrophages and VSMCs, we investigated the interactions of a biodegradable Mg-Nd-Zn-Zr alloy (denoted JDBM), which is especially important for cardiovascular stents, with VSMCs via macrophages.

Methods

JDBM extracts and MgCl₂ solutions were prepared to study their effect on macrophages. To study the effects of the JDBM extracts and MgCl₂ solutions on the function of VSMCs via immunoregulation of macrophages, conditioned media (CM) obtained from macrophages was used to establish a VSMC-macrophage indirect coculture system.

Results

Our results showed that both JDBM extracts and MgCl₂ solutions significantly attenuated the inflammatory response stimulated by lipopolysaccharide (LPS)-activated macrophages and converted macrophages into M2-type cells. In addition, JDBM extracts and MgCl₂ solutions significantly decreased the expression of genes related to VSMC phenotypic switching, migration, and proliferation in macrophages. Furthermore, the proliferation, migration, and proinflammatory phenotypic switching of VSMCs were significantly inhibited when the cells were incubated with CMs from macrophages treated with LPS + extracts or LPS + MgCl₂ solutions.

Conclusions

Taken together, our results suggested that the magnesium in the JDBM extract could affect the functions of VSMCs through macrophage-mediated immunoregulation, inhibiting smooth muscle hyperproliferation to suppress restenosis after implantation of a biodegradable Mg-based stent.

Enlargement, Reduction, and Even Reversal of Relative Migration Speeds of Endothelial and Smooth Muscle Cells on Biomaterials Simply by Adjusting RGD Nanospacing

Although many tissue regeneration processes after biomaterial implantation are related to migrations of multiple cell types on material surfaces, available tools to adjust relative migration speeds are very limited. Herein, we put forward a nanomaterial strategy to employ surface modification with arginine-glycine-aspartate (RGD) nanoarrays to tune in vitro cell migration using endothelial cells (ECs) and smooth muscle cells (SMCs) as demonstrated cell types. We found that migrations of both cell types exhibited a nonmonotonic trend with the increase of RGD nanospacing, yet with different peaks-74 nm for SMCs but 95 nm for ECs. The varied sensitivities afford a facile way to regulate the relative migration speeds. Although ECs migrated at a speed similar to SMCs on a non-nano surface, the migration of ECs could be controlled to be significantly faster or slower than SMCs simply by adjusting the RGD nanospacing. This study suggests a potential application of surface modification of biomaterials on a nanoscale level.

Development of In Vitro Endothelialised Stents - Review

Endovascular treatment is prevalent as a primary treatment for coronary and peripheral arterial diseases. Although the introduction of drug-eluting stents (DES) dramatically reduced the risk of in-stent restenosis, stent thrombosis persists as an issue. Notwithstanding improvements in newer generation DES, they are yet to address the urgent clinical need to abolish the late stent complications that result from in-stent restenosis and are associated with late thrombus formation. These often lead to acute coronary syndromes with high mortality in coronary artery disease and acute limb ischemia with a high risk of limb amputation in peripheral arterial disease. Recently, a significant amount of research has focused on alternative solutions to improve stent biocompatibility by using tissue engineering. There are two types of tissue engineering endothelialisation methods: in vitro and in vivo. To date, commercially available in vivo endothelialised stents have failed to demonstrate antithrombotic or anti-stenosis efficacy in clinical trials. In contrast, the in vitro endothelialisation methods exhibit the advantage of monitoring cell type and growth prior to implantation, enabling better quality control. The present review discusses tissue-engineered candidate stents constructed by distinct in vitro endothelialisation approaches, with a particular focus on fabrication processes, including cell source selection, stent material composition, stent surface modifications, efficacy and safety evidence from in vitro and in vivo studies, and future directions.

Recent Advances in the Development of Theranostic Nanoparticles for Cardiovascular Diseases

Cardiovascular disease (CVD) is the leading cause of death worldwide. CVD includes a group of disorders of the heart and blood vessels such as myocardial infarction, ischemic heart, ischemic injury, injured arteries, thrombosis and atherosclerosis. Amongst these, atherosclerosis is the dominant cause of CVD and is an inflammatory disease of the blood vessel wall. Diagnosis and treatment of CVD remain the main challenge due to the complexity of their pathophysiology. To overcome the limitations of current treatment and diagnostic techniques, theranostic nanomaterials have emerged. The term "theranostic nanomaterials" refers to a multifunctional agent with both therapeutic and diagnostic abilities. Theranostic nanoparticles can provide imaging contrast for a diversity of techniques such as magnetic resonance imaging (MRI), positron emission tomography (PET) and computed tomography (CT). In addition, they can treat CVD using photothermal ablation and/or medication by the drugs in nanoparticles. This review discusses the latest advances in theranostic nanomaterials for the diagnosis and treatment of CVDs according to the order of disease development. MRI, CT, near-infrared spectroscopy (NIR), and fluorescence are the most widely used strategies on theranostics for CVDs detection. Different treatment methods for CVDs based on theranostic nanoparticles have also been discussed. Moreover, current problems of theranostic nanoparticles for CVDs detection and treatment and future research directions are proposed.

Preventive Effect and Mechanism of Crossostephium chinense Extract on Balloon Angioplasty-Induced Neointimal Hyperplasia

Balloon angioplasty-induced neointimal hyperplasia remains a clinical problem that must be resolved. The bioactivities of the Crossostephium chinense extract (CCE) have demonstrated potential in preventing the progression of restenosis. The present study evaluated whether CCE can suppress balloon angioplasty-induced neointima formation and elucidated its possible pharmacological mechanisms. A rat model of carotid arterial balloon angioplasty was established to evaluate the inhibitory effect of CCEs on neointimal hyperplasia. Two cell lines, A10 vascular smooth muscle cells (VSMCs) and RAW264.7 macrophages, were used to investigate the potential regulatory activities and pharmacological mechanisms of CCEs in cell proliferation and migration and in inflammation. Our in vitro results indicated that CCE3, the ethanolic extract of C. chinense, exerted the strongest growth inhibitory and antimigratory effects on VSMCs. CCE3 blocked the activation of focal adhesion kinase, platelet-derived growth factor receptor-β (PDGFRB), and its downstream molecules (AKT and mTOR) and reduced the expression of matrix metalloproteinase-2. In addition, our findings revealed that CCE3 significantly increased the expression of miRNA-132, an inhibitory regulator of inflammation and restenosis, and suppressed the expression of inflammation-related molecules (inducible nitric oxide synthase, cyclooxygenase-2, interleukin- (IL-) 1β, and IL-6). Our in vivo study results indicated that balloon injury-induced neointimal hyperplasia was inhibited by CCE3. CCE3 could reduce neointima formation in balloon-injured arteries, and this effect may be partially attributed to the CCE3-induced suppression of PDGFRB-mediated downstream pathways and inflammation-related molecules.

Aspirin use and platelet aggregation in ischemic onset-type pediatric moyamoya patients with intractable headaches (moya-ache)

BACKGROUND

NSAIDs (nonsteroidal anti-inflammatory drugs) were administered to patients with ischemic onset-type moyamoya disease who experience headaches, but their therapeutic effect was very poor and resulted in a drop in quality of life (QOL). On the other hand, patients who were administered aspirin initially to prevent transient ischemic attacks (TIA) were observed to have a better QOL with the absence of headaches. Here, we report on patients with ischemic onset-type moyamoya disease experiencing headaches who received aspirin in order to verify its safety and effectiveness.

METHODS

From October 2012 to July 2014, 35 patients (male: 19, female: 16 average age: 10.5 ± 3.9) with ischemic onset-type pediatric moyamoya disease and who were admitted or commuted to hospital and had surgical treatment were evaluated for background, moyamoya staging (Suzuki), presence/absence of TIA, and platelet aggregation activity by adenosine diphosphate (ADP)/collagen turbidity test. The patients were divided into four groups depending on the intensity of headache prior to being administered aspirin, and the Kruskal-Wallis test was carried out for platelet aggregation activity and moyamoya staging. Also, the 4 × 2 χ² test was carried out for the presence/absence of TIA. Next, the items which were significant in these tests were used as independent variables to analyze the risk of headache onset, using logistic regression analysis.

RESULTS

One item with statistical significance was the platelet aggregation test(PAT) value (on collagen) (P < 0.0001). A logistic regression analysis was carried out, using this value as an independent variable and headache intensity-as a dependent variable. As a result, an increase in PAT value by 1 translated into 4.43 times higher risk of the onset of intractable headache, and the onset of intractable headaches was predicted at 58.8% with collagen. The risk of developing a headache decreased as a result of aspirin administration, and the decrease was dependent on the collagen-induced aggregation suppression effect of aspirin. Aspirin was administered in the range of 1.6~9.5 mg/kg/day, and the PAT value decreasing rate was 42.9% on average. One case alone experienced nasal bleeding, and all cases showed an improvement in the intractable headaches.

CONCLUSIONS

In patients with ischemic onset-type pediatric moyamoya disease who experience headaches, the platelet aggregation activity is accelerated, and aspirin administration is effective in alleviating headaches by inhibiting platelet activation, detected by the collagen PAT.

Fisetin Alleviates Neointimal Hyperplasia via PPARγ/PON2 Antioxidative Pathway in SHR Rat Artery Injury Model

The phenotypic transformation of proliferation and migration in vascular smooth muscle cells (VSMCs) from media to intima is the basic pathology of neointimal hyperplasia after angioplasty in hypertensive patients. Angiotensin II (AngII) stimulates oxidative stress in VSMC, inducing VSMC proliferation and migration, which is a critical factor in both developments of hypertension and angioplasty-induced arterial restenosis. Fisetin, a plant flavonoid polyphenol, has been reported to be antioxidative and potent senolytic. It is unknown whether fisetin would inhibit neointimal hyperplasia. Therefore, we investigated the role of fisetin in neointimal formation in vitro and in vivo. The rat thoracic aortic smooth muscle cells (A10 cells) stimulated by AngII were used as the in vitro neointimal hyperplasia model, where AngII significantly induced the proliferation and migration in A10 cells. We found that fisetin could dose-dependently inhibit the effect of AngII via inducing the expression of an antioxidant, paraoxonase-2 (PON2), whose overexpression could inhibit the proliferation and migration of A10 cells and downexpression by siRNA had the opposite effect. Furthermore, we found the mechanism of fisetin's inducing PON2 expression involved PPARγ. Rosiglitazone, a PPARγ agonist, could increase PON2 expression in A10 cells, while the PPARγ inhibitor prevented the effect of fisetin on PON2. The in vivo neointimal hyperplasia model was established 2 weeks after the carotid artery balloon injury in SHR rats. Administration of fisetin (ip 3 mg/kg daily for 2 weeks) right after the injury significantly increased PON2 expression in the artery, inhibiting ROS production, and efficiently reduced carotid neointimal hyperplasia. These results indicate that fisetin increases the expression of antioxidant PON2 via activation of PPARγ, reducing oxidative stress, inhibiting VSMC proliferation and migration, and alleviates neointimal hyperplasia after intimal injury. PON2 may be a potential therapeutic target to reduce arterial remodeling after angioplasty in hypertensive patients.

Relationship between vascular cell adhesion molecule-1 (VCAM-1), soluble receptor for advanced glycation end products (sRAGE) and functional hemodynamic parameters of arteriovenous fistula

BACKGROUND

The preferred vascular access for hemodialysis is represented by arteriovenous fistula (AVF) due to fewer complications and more prolonged survival. Considerable efforts have been made to identify biomarkers associated with AVF dysfunction, but results are conflicting. Vascular cell adhesion molecule (VCAM-1) and advanced glycation end products are involved in atherogenesis, vascular calcification, peripheral artery disease, and neointimal hyperplasia in renal and non-renal patients. The objective of this study was to evaluate whether there is an association between VCAM-1, soluble receptor for advanced glycation end products (sRAGE), NcarboxymethylLysine (CML), and arteriovenous fistula dysfunction (AVF).

METHODS

VCAM-1, sRAGE, and CML were performed using the ELISA technique in 88 HD patients. Ultrasound assessment of AVF reports brachial artery blood flow (Qa), brachial resistivity index (RI), presence of calcification, and the diameter. AVF dysfunction was defined as a brachial artery Qa ⩽ 500 ml/min or RI ⩾ 0.5.

RESULTS

The median level of VCAM-1 [2676.5(2206.8-4203.9) versus 2613.2(1885.7-3161.8), p 0.026] was significantly higher in patients with AVF dysfunction compared to the rest of the patients. sRAGE and CML were higher in this group but without statistical significance. In patients with AVF dysfunction, significant positive correlations were found between VCAM-1and sRAGE (r = 0.417, p = 0.001), RI (r = 0.313, p = 0.046), dialysis vintage (r = 0.540, p < 0.001), AVF vintage (r = 0.336, p = 0.032), intima-media thickness (r = 0.423, p = 0.006) and C-reactive protein (r = 0.315, p = 0.045). VCAM-1 correlated inversely with cholesterol (r = -0.312, p = 0.047), triglycerides (r = -0.358, p = 0.021), body mass index (r = -0.388, p = 0.012). In multivariate regression analysis, VCAM-1 (p = 0.013) and sRAGE (p = 0.01) remained significant predictors of RI and Qa. Logistic regression disclosed calcification, VCAM-1, as risks factors for AVF dysfunction.

CONCLUSION

The results we obtained showed that patients with AVF dysfunction had a significantly higher level of VCAM-l. A positive correlation between VCAM-1 and sRAGE was identified in this group.

Curcumin inhibits proliferation, migration and neointimal formation of vascular smooth muscle via activating miR-22

Context: Curcumin has antitumor, antioxidative, anti-inflammatory, and anti-proliferative properties.Objective: To investigate the role of miR-22 during curcumin-induced changes in vascular smooth muscle cells (VSMC) and neointima formation in balloon-injured rat abdominal aorta.Materials and methods: Sprague-Dawley rats were randomised to the sham-operated (n = 10), operated control (injured, n = 10), and curcumin treatment (n = 10) groups. miR-22 expression was determined by real-time PCR. SP1 was assessed by western blot and real-time PCR. Rat aortic smooth muscle A7r5 cells were used to determine VSMC proliferation and migration, which were measured by the MTS, EdU staining, Transwell, and wound healing assays.Results: miR-22 levels declined following arterial balloon injury in vivo (48% at 3d, p < 0.05) and serum stimulation in vitro (45% at 24 h, p < 0.01). Functional studies revealed that miR-22 negatively regulated the proliferation and migration of VSMCs by directly targeting the SP1 transcription factor in VSMCs. Curcumin increased the expression of miR-22 (81%, p < 0.05) and decreased the protein expression of SP1 in VSMCs (25%, p < 0.05). miR-22 inhibition was found to attenuate the effects of curcumin on VSMC functions. Curcumin increased miR-22 (46%, p < 0.01), decreased the SP1 protein (19%, p < 0.05), and inhibited vascular neointimal area (48%, p < 0.01) in vivo.Discussion: The miR-22/SP1 pathway is involved in the protective role of curcumin during arterial balloon injury, but the mechanisms remain unclear.Conclusion: miR-22 is involved in the inhibitory effects of curcumin on VSMCs' proliferation, migration and neointima hyperplasia after arterial balloon injury in rats. Curcumin could be used to prevent neointimal hyperplasia after angioplasty.

Longitudinal Monitoring of Flow-Diverting Stent Tissue Coverage After Implant in a Bifurcation Model Using Neurovascular High-Frequency Optical Coherence Tomography

BACKGROUND

Tissue growth over covered branches is a leading cause of delayed thrombotic complications after flow-diverter stenting (FDS). Due to insufficient resolution, no imaging modality is clinically available to monitor this phenomenon.

OBJECTIVE

To evaluate high-frequency optical coherence tomography (HF-OCT), a novel intravascular imaging modality designed for the cerebrovascular anatomy with a resolution approaching 10 microns, to monitor tissue growth over FDS in an arterial bifurcation model.

METHODS

FDS were deployed in a rabbit model (n = 6), covering the aortic bifurcation. The animals were divided in different groups, receiving dual antiplatelet therapy (DAPT) (n = 4), aspirin only (n = 1), and no treatment (n = 1). HF-OCT data were obtained in vivo at 3 different time points in each animal. For each cross-sectional image, metal and tissue coverage of the jailed ostium was quantified. Scanning electron microscopy images of harvested arteries were subsequently obtained.

RESULTS

Good quality HF-OCT data sets were successfully acquired at implant and follow-up. A median value of 41 (range 21-55) cross-sectional images were analyzed per ostium for each time point. Between 0 and 30 d after implant, HF-OCT analysis showed a significantly higher ostium coverage when DAPT was not given. After 30 d, similar growth rates were found in the DAPT and in the aspirin group. At 60 d, a coverage of 90% was reached in all groups.

CONCLUSION

HF-OCT enables an accurate visualization of tissue growth over time on FDS struts. The use of FDS in bifurcation locations may induce a drastic reduction of the jailed-branch ostium area.

Vessel Wall-Derived Mesenchymal Stromal Cells Share Similar Differentiation Potential and Immunomodulatory Properties with Bone Marrow-Derived Stromal Cells

Purpose

This study is aimed at investigating the phenotype, differentiation potential, immunomodulatory properties, and responsiveness of saphenous vein vessel wall-derived mesenchymal stromal cells (SV-MSCs) to various TLR ligands and proinflammatory cytokines, as well as comparing their features to those of their bone marrow-derived counterparts (BM-MSCs).

Methods

SV-MSCs were isolated by enzymatic digestion of the saphenous vein vessel wall. Phenotype analysis was carried out by flow cytometry and microscopy, whereas adipogenic, chondrogenic, and osteogenic differentiation potentials were tested in in vitro assays. For comparative analysis, the expression of different stemness, proliferation, and differentiation-related genes was determined by Affymetrix gene array. To compare the immunomodulatory properties of SV-MSCs and BM-MSCs, mixed lymphocyte reaction was applied. To investigate their responses to various activating stimuli, MSCs were treated with TLR ligands (LPS, PolyI:C) or proinflammatory cytokines (TNFα, IL-1β, IFNγ), and the expression of various early innate immune response-related genes was assessed by qPCR, while secretion of selected cytokines and chemokines was measured by ELISA.

Results

The isolated SV-MSCs were able to differentiate into bone, fat, and cartilage cells/direction in vitro. SV-MSCs expressed the most important MSC markers (CD29, CD44, CD73, CD90, and CD105) and shared almost identical phenotypic characteristics with BM-MSCs. Their gene expression pattern and activation pathways were close to those of BM-MSCs. SV-MSCs showed better immunosuppressive activity inhibiting phytohemagglutinin-induced T lymphocyte proliferation in vitro than BM-MSCs. Cellular responses to treatments mimicking inflammatory conditions were comparable in the bone marrow- and saphenous vein-derived MSCs. Namely, similar to BM-MSCs, SV-MSCs secreted increased amount of IL-6 and IL-8 after 12- or 24-hour treatment with LPS, PolyI:C, TNFα, or IL-1β, compared to untreated controls. Interestingly, a different CXCL-10/IP-10 secretion pattern could be observed under inflammatory conditions in the two types of MSCs.

Conclusion

Based on our results, cells isolated from saphenous vein vessel wall fulfilled the ISCT's (International Society for Cellular Therapy) criteria for multipotent mesenchymal stromal cells, and no significant differences in the phenotype, gene expression pattern, and responsiveness to inflammatory stimuli could be observed between BM-MSCs and SV-MSCs, while the latter cells have more potent immunosuppressive activity in vitro. Further functional assays have to be performed to reveal whether SV-MSCs could be useful for certain regenerative therapeutic applications or tissue engineering purposes.

M2 macrophage-derived exosomes promote the c-KIT phenotype of vascular smooth muscle cells during vascular tissue repair after intravascular stent implantation

Rationale: For intravascular stent implantation to be successful, the processes of vascular tissue repair and therapy are considered to be critical. However, the mechanisms underlying the eventual fate of vascular smooth muscle cells (VSMCs) during vascular tissue repair remains elusive. In this study, we hypothesized that M2 macrophage-derived exosomes to mediate cell-to-cell crosstalk and induce dedifferentiation phenotypes in VSMCs. Methods: In vivo, 316L bare metal stents (BMS) were implanted from the left iliac artery into the abdominal aorta of 12-week-old male Sprague-Dawley (SD) rats for 7 and 28 days. Hematoxylin and eosin (HE) were used to stain the neointimal lesions. En-face immunofluorescence staining of smooth muscle 22 alpha (SM22α) and CD68 showed the rat aorta smooth muscle cells (RASMCs) and macrophages. Immunohistochemical staining of total galactose-specific lectin 3 (MAC-2) and total chitinase 3-like 3 (YM-1) showed the total macrophages and M2 macrophages. In vitro, exosomes derived from IL-4+IL-13-treated macrophages (M2Es) were isolated by ultracentrifugation and characterized based on their specific morphology. Ki-67 staining was conducted to assess the effects of the M2Es on the proliferation of RASMCs. An atomic force microscope (AFM) was used to detect the stiffness of the VSMCs. GW4869 was used to inhibit exosome release. RNA-seq was performed to determine the mRNA profiles of the RASMCs and M2Es-treated RASMCs. Quantitative real-time PCR (qRT-PCR) analysis was conducted to detect the expression levels of the mRNAs. Western blotting was used to detect the candidate protein expression levels. T-5224 was used to inhibit the DNA binding activity of AP-1 in RASMCs. Results: M2Es promote c-KIT expression and softening of nearby VSMCs, hence accelerating the vascular tissue repair process. VSMCs co-cultured in vitro with M2 macrophages presented an increased capacity for de-differentiation and softening, which was exosome dependent. In addition, the isolated M2Es helped to promote VSMC dedifferentiation and softening. Furthermore, the M2Es enhanced vascular tissue repair potency by upregulation of VSMCs c-KIT expression via activation of the c-Jun/activator protein 1 (AP-1) signaling pathway. Conclusions: The findings of this study emphasize the prominent role of M2Es during VSMC dedifferentiation and vascular tissue repair via activation of the c-Jun/AP-1 signaling pathway, which has a profound impact on the therapeutic strategies of coronary stenting techniques.

Atherosclerosis and Nanomedicine Potential: Current Advances and Future Opportunities

Atherosclerosis is the leading inducement of cardiovascular diseases, which ranks the first cause of global deaths. It is an arterial disease associated with dyslipidemia and changes in the composition of the vascular wall. Besides invasive surgical strategy, the current conservative clinical treatment for atherosclerosis falls into two categories, lipid regulating-based therapy and antiinflammatory therapy. However, the existing strategies based on conventional drug delivery systems have shown limited efficacy against disease development and plenty of side effects. Nanomedicine has great potential in the development of targeted therapy, controlled drug delivery and release, the design of novel specific drugs and diagnostic modalities, and biocompatible scaffolds with multifunctional characteristics, which has led to an evolution in the diagnosis and treatment of atherosclerosis. This paper will focus on the latest nanomedicine strategies for atherosclerosis diagnosis and treatment as well as discussing the potential therapeutic targets during atherosclerosis progress, which could form the basis of development of novel nanoplatform against atherosclerosis.

Therapeutic modulation of RNA-binding protein Rbm38 facilitates re-endothelialization after arterial injury

Aims

Delayed re-endothelialization after balloon angioplasty in patients with coronary or peripheral artery disease impairs vascular healing and leads to neointimal proliferation. In the present study, we examined the effect of RNA-binding motif protein 38 (Rbm38) during re-endothelialization in a murine model of experimental vascular injury.

Methods and results

Left common carotid arteries of C57BL/6 mice were electrically denudated and endothelial regeneration was evaluated. Profiling of RNA-binding proteins revealed dysregulated expression of Rbm38 in the denudated and regenerated areas. We next tested the importance of Rbm38 in human umbilical vein endothelial cells (HUVECS) and analysed its effects on cellular proliferation, migration and apoptosis. Rbm38 silencing in vitro demonstrated important beneficial functional effects on migratory capacity and proliferation of endothelial cells. In vivo, local silencing of Rbm38 also improved re-endothelialization of denuded carotid arteries. Luciferase reporter assay identified miR-98 and let-7f to regulate Rbm38 and the positive proliferative properties of Rbm38 silencing in vitro and in vivo were mimicked by therapeutic overexpression of these miRNAs.

Conclusion

The present data identified Rbm38 as an important factor of the regulation of various endothelial cell functions. Local inhibition of Rbm38 as well as overexpression of the upstream regulators miR-98 and let-7f improved endothelial regeneration in vivo and thus may be a novel therapeutic entry point to avoid endothelial damage after balloon angioplasty.

Role of the Endocannabinoidome in Human and Mouse Atherosclerosis

The Endocannabinoid (eCB) system and its role in many physiological and pathological conditions is well described and accepted, and includes cardiovascular disorders. However, the eCB system has been expanded to an "-ome"; the endocannabinoidome (eCBome) that includes endocannabinoid-related mediators, their protein targets and metabolic enzymes, many of which significantly impact upon cardiometabolic health. These recent discoveries are here summarized with a special focus on their potential involvement in atherosclerosis. We described the role of classical components of the eCB system (eCBs, CB1 and CB2 receptors) and eCB-related lipids, their regulatory enzymes and molecular targets in atherosclerosis. Furthermore, since increasing evidence points to significant cross-talk between the eCBome and the gut microbiome and the gut microbiome and atherosclerosis, we explore the possibility that a gut microbiome - eCBome axis has potential implications in atherosclerosis.

Characterization of carotid endothelial cell proliferation on Au, Au/GO, and Au/rGO surfaces by electrical impedance spectroscopy

To the best of the authors' knowledge, testing the biocompatibility of graphene coatings can be considered as the first to demonstrate human carotid endothelial cell (HCtAEC) proliferation on Au, graphene oxide-coated Au (Au/GO), and reduced graphene oxide-coated Au (Au/rGO) surfaces. We hypothesized that stent material modified with graphene (G)-based coatings could be used as electrodes for electrical impedance spectroscopy (EIS) in monitoring cell cultures, i.e., endothelialization. Alamar Blue cell viability assay and cell staining and cell counting with optical images were performed. For EIS analysis, an EIS sensor consisting of Au surface electrodes was produced by the photolithographic technique. Surface characterizations were performed by considering scanning electron microscope (SEM) and water contact angle analyses. Results showed that GO and rGO coatings did not prevent neither the electrical measurements nor the cell proliferation and that rGO had a positive effect on HCtAEC proliferation. The rate of increase of impedance change from day 1 to day 10 was nearly fivefold for all electrode surfaces. Alamar Blue assay performed to monitor cell proliferation rates between groups, and rGO has shown the highest Alamar Blue reduction value of 43.65 ± 8.79%. Graphical abstract.

Impact of stent of ductus arteriosus and modified Blalock-Taussig shunt on pulmonary arteries growth and second-stage surgery in infants with ductus-dependent pulmonary circulation

Introduction

Ducts-dependent pulmonary circulation is spectrum of congenital heart diseases that need urgent intervention to augment pulmonary blood. Systemic to pulmonary shunt is the classical surgical management. Stenting of ductus arteriosus emerged in the last 2 decades as an alternative plausible intervention.

Objectives

To evaluate and compare the short and midterm effects of PDA stenting in compared to surgically placed shunt for augmentation of pulmonary blood flow looking to pulmonary artery (PA) branches growth, oxygen saturation and suitability for second stage repair.

Methods

We conducted this prospective study in Cardiac Surgical Intensive Care Unit. Cases were divided into "stent group" and "surgical shunt" group. Results were compared between two groups regarding oxygen saturation, mechanical ventilation duration, intensive care stay, mortality and morbidity. Growth of PA branches was assessed during follow up by echocardiograph. Nakata index score was calculated by angiogram before second stage surgery and was compared between both groups.

Results

43 patients were included. Forty-two cases were offered stent as initial management. 6/42 cases failed stenting (14%) and 3/42 (7%) required late BT shunt after PDA stenting. 10/43 cases ended up receiving BT shunt and were counted as "surgical shunt group". Stent group (33 cases) needed less mechanical ventilation (2.08 ± 0.65 vs.7.8 ± 4 days with p = 0.014), and less ICU stay compared with surgical shunt group (6.2 ± 1.02 vs. 14 ± 4.5 days, P = 0.009). Both groups achieved similar growth of pulmonary artery branches (p = 0.6 for Z score of left pulmonary artery and P = 0.8 for Z score for right pulmonary artery). Although "stent group" reached second stage surgery with lower O2 saturation 67.6 ± 4.6 vs. 80 ± 4.2 in "surgical shunt" group with P value = 0.0002). Majority of patients in both groups had some PA distortion and needed surgical reconstruction in main pulmonary artery or in its main branches during second stage repair. 3 cases (7.1%) died soon post stenting versus none in surgical shunt group (p = value 0.57).

Conclusions

In neonates with ductus-dependent pulmonary circulation PDA stenting can be introduced as safe first possible option to augment pulmonary blood flow with good outcome and suitable preparation for second stage palliation.

Transcriptomic profiling of experimental arterial injury reveals new mechanisms and temporal dynamics in vascular healing response

Objective

Endovascular interventions cause arterial injury and induce a healing response to restore vessel wall homeostasis. Complications of defective or excessive healing are common and result in increased morbidity and repeated interventions. Experimental models of intimal hyperplasia are vital for understanding the vascular healing mechanisms and resolving the clinical problems of restenosis, vein graft stenosis, and dialysis access failure. Our aim was to systematically investigate the transcriptional, histologic, and systemic reaction to vascular injury during a prolonged time.

Methods

Balloon injury of the left common carotid artery was performed in male rats. Animals (n = 69) were euthanized before or after injury, either directly or after 2 hours, 20 hours, 2 days, 5 days, 2 weeks, 6 weeks, and 12 weeks. Both injured and contralateral arteries were subjected to microarray profiling, followed by bioinformatic exploration, histologic characterization of the biopsy specimens, and plasma lipid analyses.

Results

Immune activation and coagulation were key mechanisms in the early response, followed by cytokine release, tissue remodeling, and smooth muscle cell modulation several days after injury, with reacquisition of contractile features in later phases. Novel pathways related to clonal expansion, inflammatory transformation, and chondro-osteogenic differentiation were identified and immunolocalized to neointimal smooth muscle cells. Analysis of uninjured arteries revealed a systemic component of the reaction after local injury, underlined by altered endothelial signaling, changes in overall tissue bioenergy metabolism, and plasma high-density lipoprotein levels.

Conclusions

We demonstrate that vascular injury induces dynamic transcriptional landscape and metabolic changes identifiable as early, intermediate, and late response phases, reaching homeostasis after several weeks. This study provides a temporal “roadmap” of vascular healing as a publicly available resource for the research community.

Endovascular intervention causes an injury to the arterial wall that subsequently induces a healing response to restore the vessel wall homeostasis. Complications after vascular interventions related to defective or excessive healing response, such as thrombosis or restenosis, are common and result in increased morbidity, suffering of the patient, need for repeated interventions, and possibly death. Thus, there is a need for better understanding of the underlying molecular mechanisms during vascular injury and healing response to identify and to assess the risk of complications in patients. Using an experimental model of vascular injury, this study demonstrates the full landscape of dynamic transcriptional changes in the resolution of vascular injury, accompanied also by systemic variations in plasma lipid levels and reaching homeostasis several weeks after injury. These results can guide the development of new strategies and molecular targets for modulation of the intimal response on endovascular interventions.

Covalent attachment of resveratrol to stainless steel toward the development of a resveratrol-releasing bare-metal stent

Herein, we describe the covalent attachment of resveratrol, a naturally occurring antioxidant, to the surface of stainless-steel as a model for designing a novel bare-metal stent to treat coronary artery disease. Resveratrol has been shown to reduce oxidative stress in dysfunctional endothelial cells, and stimulate arterial healing. Resveratrol treatments, however, are limited by low water solubility, such that a localized delivery to the site of arterial narrowing via a coated stent presents a promising strategy for improving stent outcomes. Our attachment strategy utilizes zirconium vapor deposition to lay down a thin layer of zirconium oxide with labile hydrocarbon groups at the surface. Resveratrol can displace these hydrocarbons in aprotic solvent to afford a covalently attached layer of resveratrol. We evaluated the release of resveratrol under a range of pH levels, including physiological conditions (pH = 7.4 and 37 °C). Furthermore, we established that endothelial cells grown on a resveratrol-bound surface release elevated nitric oxide levels compared to controls, a key endothelial signaling molecule responsible for arterial health. These results are promising toward the development of a resveratrol-coated bare-metal stent to improve patient outcomes.

A Review of the Ultrathin Orsiro Biodegradable Polymer Drug-eluting Stent in the Treatment of Coronary Artery Disease

Drug-eluting stents (DES) have revolutionised the treatment of coronary artery disease (CAD) in patients undergoing percutaneous coronary intervention. In recent years, there has been a focus on a new generation of DES, such as biodegradable polymer DES (BP-DES). This novel stent platform was developed with the hope of eliminating the risk of very late stent thrombosis associated with the current gold-standard durable polymer DES (DP-DES). Ultrathin Orsiro BP-DES (Biotronik, Bülach, Switzerland) are based on a cobalt-chromium stent platform that is coated with a bioresorbable polymer coating containing sirolimus. These devices have one of the thinnest struts available in the current market and have the theoretical benefit of reducing a chronic inflammatory response in the vessel wall. In 2019, the United States Food and Drug Administration (FDA) approved the use of Orsiro BP-DES in patients with CAD based on promising results in recent landmark trials, such as BIOFLOW V and BIOSTEMI. The aim of the present review article was to discuss the history of stent technology and the continued opportunities for improvements, focusing on the potential benefits of Orsiro BP-DES.

Location-Specific Comparison Between a 3D In-Stent Restenosis Model and Micro-CT and Histology Data from Porcine In Vivo Experiments

BACKGROUND

Coronary artery restenosis is an important side effect of percutaneous coronary intervention. Computational models can be used to better understand this process. We report on an approach for validation of an in silico 3D model of in-stent restenosis in porcine coronary arteries and illustrate this approach by comparing the modelling results to in vivo data for 14 and 28 days post-stenting.

METHODS

This multiscale model includes single-scale models for stent deployment, blood flow and tissue growth in the stented vessel, including smooth muscle cell (SMC) proliferation and extracellular matrix (ECM) production. The validation procedure uses data from porcine in vivo experiments, by simulating stent deployment using stent geometry obtained from micro computed tomography (micro-CT) of the stented vessel and directly comparing the simulation results of neointimal growth to histological sections taken at the same locations.

RESULTS

Metrics for comparison are per-strut neointimal thickness and per-section neointimal area. The neointimal area predicted by the model demonstrates a good agreement with the detailed experimental data. For 14 days post-stenting the relative neointimal area, averaged over all vessel sections considered, was 20 ± 3% in vivo and 22 ± 4% in silico. For 28 days, the area was 42 ± 3% in vivo and 41 ± 3% in silico.

CONCLUSIONS

The approach presented here provides a very detailed, location-specific, validation methodology for in silico restenosis models. The model was able to closely match both histology datasets with a single set of parameters. Good agreement was obtained for both the overall amount of neointima produced and the local distribution. It should be noted that including vessel curvature and ECM production in the model was paramount to obtain a good agreement with the experimental data.

Hydrogen sulfide-releasing peptide hydrogel limits the development of intimal hyperplasia in human vein segments

Currently available interventions for vascular occlusive diseases suffer from high failure rates due to re-occlusive vascular wall adaptations, a process called intimal hyperplasia (IH). Naturally occurring hydrogen sulfide (H2S) works as a vasculoprotective gasotransmitter in vivo. However, given its reactive and hazardous nature, H2S is difficult to administer systemically. Here, we developed a hydrogel capable of localized slow release of precise amounts of H2S and tested its benefits on IH. The H2S-releasing hydrogel was prepared from a short peptide attached to an S-aroylthiooxime H2S donor. Upon dissolution in aqueous buffer, the peptide self-assembled into nanofibers, which formed a gel in the presence of calcium. This new hydrogel delivered H2S over the course of several hours, in contrast with fast-releasing NaHS. The H2S-releasing peptide/gel inhibited proliferation and migration of primary human vascular smooth muscle cells (VSMCs), while promoting proliferation and migration of human umbilical endothelial cells (ECs). Both NaHS and the H2S-releasing gel limited IH in human great saphenous vein segments obtained from vascular patients undergoing bypass surgery, with the H2S-releasing gel showing efficacy at a 5x lower dose than NaHS. These results suggest local perivascular H2S release as a new strategy to limit VSMC proliferation and IH while promoting EC proliferation, hence re-endothelialization. STATEMENT OF SIGNIFICANCE: Arterial occlusive disease is the leading cause of death in Western countries, yet current therapies suffer from high failure rates due to intimal hyperplasia (IH), a thickening of the vascular wall leading to secondary vessel occlusion. Hydrogen sulfide (H2S) is a gasotransmitter with vasculoprotective properties. Here we designed and synthesized a peptide-based H2S-releasing hydrogel and found that local application of the gel reduced IH in human vein segments obtained from patients undergoing bypass surgery. This work provides the first evidence of H2S efficacy against IH in human tissue, and the results show that the gel is more effective than NaHS, a common instantaneous H2S donor.

Soft-sheath, stiff-core microfiber hydrogel for coating vascular implants

Vascular implants remain clinically challenged due to often-occurring thrombosis and stenosis. Critical to addressing these complications is the design of implant material surfaces to inhibit the activities of platelets, smooth muscle cells (SMCs) and inflammatory cells. Recent mechanobiology studies accentuate the significance of material elasticity to cells and tissues. We thus developed and characterized an implant coating composed of hybrid, viscoelastic microfibers with coaxial core-sheath nanostructure. The coating over metallic stent material was formed by first depositing coaxially-electrospun fibers of poly(L-lactic acid) core and polyethylene glycol dimethacrylate sheath, and then polymerizing fibers with various UV times. Material characterizations were performed to evaluate the coating structure, mechanical property and biocompatibility. Results showed that coaxial microfibers exhibited arterial-like mechanics. The soft surface, high water content and swelling ratio of the coaxial fibers resemble hydrogels, while they are mechanically strong with an elastic modulus of 172-729 kPa. The coating strength and surface elasticity were tunable with the photopolymerization time. Further, the elastic fibers, as conformal coating on stent metal, strongly reduced SMC overgrowth and discouraged platelet adhesion and activation, compared to bare metals. Importantly, after 7-day subcutaneous implantation, coaxial fiber-coated implants showed more favorable in vivo responses with reduced tissue encapsulation, compared to bare stent metals or those coated with a two-layered fiber mixture composed of fibers from individual polymers. The excellent biocompatibility aroused from nanostructural interfaces of hybrid fibers offering hydrated, soft, nonfouling microenvironments. Such integrated fiber system may allow creation of advanced vascular implants that possess physico-mechanical properties of native arteries.