Coronary stents and vascular response to implantation: literature review

Biological response of degradation products of PEO-modified magnesium on vascular tissue cells, hemocompatibility and its influence on the inflammatory response

Cardiovascular stenting is the most widely used therapy to treat coronary artery disease caused by partial or total obstruction of the artery due to atherosclerotic plaque formation, with potentially fatal effects. There are different types of stents: bare metal stents, drug-eluting stents, bioabsorbable stents and dual therapy stents. However, they can lead to long-term complications, such as in-stent restenosis and late thrombosis. To reduce these adverse effects, research has focused on biodegradable metallic stents, since they retain the mechanical properties necessary to contain the injured artery while it is being repaired and, once their function has been fulfilled, the stent degrades without altering the system or compromising the patient's health. In this work we have evaluated the biological response of the degradation products of a bare Mg based biomaterial surface-modified by the plasma electrolytic oxidation (PEO) method on vascular tissue cells, hemocompatibility and inflammatory response. The results obtained are compatible with a biosafe material for future use as a cardiovascular implant, but it is necessary to continue with in vivo and mechanical properties tests to ensure and guarantee its use. SIGNIFICANCE STATEMENT: The development of fully bioresorbable stents is a promising alternative for the management of coronary artery disease without causing long-term problems at the implantation site. In this work, the hematological and immunological biocompatibility of bare Mg modified superficially by plasma electrolytic oxidation (PEO-Mg) was evaluated by in vitro and ex vivo assays. PEO-Mg was found to be compatible with blood and immune components surrounding the implantation site with no signs of toxicity to endothelial cells, macrophages, and arterial tissue. In addition, degradation products of PEO-Mg are eliminated by phagocytosis. However, an in-depth study of the physical and mechanical properties and in vivo biocompatibility must be carried out for its future use as a biomedical implant.

Evaluation of coronary stents: A review of types, materials, processing techniques, design, and problems

In the world, one of the leading causes of death is coronary artery disease (CAD). There are several ways to treat this disease, and stenting is currently the most appropriate way in many cases. Nowadays, the use of stents has rapidly increased, and they have been introduced in various models, with different geometries and materials. To select the most appropriate stent required, it is necessary to have an analysis of the mechanical behavior of various types of stents. The purpose of this article is to provide a complete overview of advanced research in the field of stents and to discuss and conclude important studies on different topics in the field of stents. In this review, we introduce the types of coronary stents, materials, stent processing technique, stent design, classification of stents based on the mechanism of expansion, and problems and complications of stents. In this article, by reviewing the biomechanical studies conducted in this field and collecting and classifying their results, a useful set of information has been presented to continue research in the direction of designing and manufacturing more efficient stents, although the clinical-engineering field still needs to continue research to optimize the design and construction. The optimum design of stents in the future is possible by simulation and using numerical methods and adequate knowledge of stent and artery biomechanics.

Multimodal effects of asymmetric coating of coronary stents by electrospinning and electrophoretic deposition

Drug-eluting stents (DESs) are drug-coated vascular implants that inhibit smooth muscle cell proliferation and limit in-stent re-stenosis. However, traditional DESs release a single drug into the blood and cannot cope with complex mechanisms in atherosclerosis and body responses. The present study aimed to develop a novel multimodal stent by fabricating asymmetric coating with electrophoretic deposition and electrospinning. Herein, we use heparin-loaded alginate (Hep/Alg) and atorvastatin calcium-loaded polyurethane (AtvCa/PU) coatings on the stent luminal and abluminal surfaces, respectively. Scanning electron microscopy (SEM) micrographs showed that the alginate coatings had uniformity and thin thickness. Meanwhile, the PU fibers were formed without beads, with an acceptable diameter and suitable mechanical properties. PU nanofiber revealed minimal degradation in a 1-month study. The release of AtvCa and Hep continued for 8 days without a significant initial burst release. None of the stent coatings were cytotoxic or hemolytic, and PU nanofibers supported the survival of human umbilical endothelial cells (HUVEC) with high adhesion and flattened morphologies. The results indicate that electrophoretic deposition and electrospinning have significant potential for achieving asymmetric coating on stents and a promising approach for dual drug release for multimodal effects in vascular stent applications.

Advanced Strategies to Thwart Foreign Body Response to Implantable Devices

Mitigating the foreign body response (FBR) to implantable medical devices (IMDs) is critical for successful long‐term clinical deployment. The FBR is an inevitable immunological reaction to IMDs, resulting in inflammation and subsequent fibrotic encapsulation. Excessive fibrosis may impair IMDs function, eventually necessitating retrieval or replacement for continued therapy. Therefore, understanding the implant design parameters and their degree of influence on FBR is pivotal to effective and long lasting IMDs. This review gives an overview of FBR as well as anti‐FBR strategies. Furthermore, we highlight recent advances in biomimetic approaches to resist FBR, focusing on their characteristics and potential biomedical applications.

Bio-inspired flexible electronics for smart E-skin

"Learning from nature" provides endless inspiration for scientists to invent new materials and devices. Here, we review state-of-the-art technologies in flexible electronics, with a focus on bio-inspired smart skins. This review focuses on the development of E-skin for sensing a variety of parameters such as mechanical loads, temperature, light, and biochemical cues, with a trend of increased integration of multiple functions. It highlights the most recent advances in flexible electronics inspired by animals such as chameleons, squids, and octopi whose bodies have remarkable camouflage, mimicry, or self-healing attributes. Implantable devices, being overlapped with smart E-skin in a broad sense, are included in this review. This review outlines the remaining challenges in flexible electronics and the prospects for future development for biomedical applications. STATEMENT OF SIGNIFICANCE: This article reviews the state-of-the-art technologies of bio-inspired smart electronic skin (E-skin) developed in a "learning-mimicking-creating" (LMC) cycle. We emphasize the most recent innovations in the development of E-skin for sensing physical changes and biochemical cues, and for integrating multiple sensing modalities. We discuss the achievements in implantable materials, wireless communication, and device design pertaining to implantable flexible electronics. This review will provide prospective insights integrating material, electronics, and mechanical engineering viewpoints to foster new ideas for next-generation smart E-skin.

Predictive Value Analysis of in-Stent Restenosis Within Three Years in Older Acute Coronary Syndrome Patients: A Two-Center Retrospective Study

We aimed to investigate prognostic factors of in-stent restenosis (ISR) within 3 years in older acute coronary syndrome (ACS) patients after drug-eluting stent (DES) implantation and establish a clinical model for predicting ISR. We retrospectively collected 215 older ACS patients who followed coronary angiography (CAG) after DES implantation, divided into ISR group and non in-stent restenosis (non-ISR) group according to the results of reviewed CAG. Logistic regression analysis was performed to screen independent predictors related to ISR and build the clinical predictive model, which clinical application was assessed by decision curve analysis (DCA) and clinical impact curve (CIC). Kaplan-Meier survival curves for ISR by independent predictors. In multivariate logistic regression analysis showed that the red cell distribution width (RDW) was higher in ISR group compared with non-ISR (odds ratio (OR) = 1.54, 95% confidence interval (CI): 1.14–2.08, p < 0.01). Instead, a negative correlation was observed between minimum stent diameter and ISR (OR = 0.28, 95%CI:0.09-0.86, p = 0.03). A novel nomogram composed of these significant features presented a concordance index (C-index) of 0.710, DCA and CIC suggested that the predictive nomogram had clinical utility. Schoenfeld residuals showed the model RDW ≥ 12.6% with minimum stent diameter <3 mm was consistent with the proportional risk assumption. The Kaplan-Meier estimate for ISR showed statistical significance. Higher levels of RDW and lower minimum stent diameter were associated with incidence of ISR within 3 years in older ACS patients after DES implantation.

Design and Analysis of a Biodegradable Polycaprolactone Flow Diverting Stent for Brain Aneurysms

The flow diverting stent (FDS) has become a promising endovascular device for the treatment of aneurysms. This research presents a novel biodegradable and non-braided Polycaprolactone (PCL) FDS. The PCL FDS was designed and developed using an in-house fabrication unit and coated on two ends with BaSO₄ for angiographic visibility. The mechanical flexibility and quality of FDS surfaces were examined with the UniVert testing machine, scanning electron microscope (SEM), and 3D profilometer. Human umbilical vein endothelial cell (HUVEC) adhesion, proliferation, and cell morphology studies on PCL FDS were performed. The cytotoxicity and NO production by HUVECs with PCL FDS were also conducted. The longitudinal tensile, radial, and bending flexibility were found to be 1.20 ± 0.19 N/mm, 0.56 ± 0.11 N/mm, and 0.34 ± 0.03 N/mm, respectively. The FDS was returned to the original shape and diameter after repeated compression and bending without compromising mechanical integrity. Results also showed that the proliferation and adhesion of HUVECs on the FDS surface increased over time compared to control without FDS. Lactate dehydrogenase (LDH) release and NO production showed that PCL FDS were non-toxic and satisfactory. Cell morphology studies showed that HUVECs were elongated to cover the FD surface and developed an endothelial monolayer. This study is a step forward toward the development and clinical use of biodegradable flow diverting stents for endovascular treatment of the aneurysm.

Clonal diversity of the B cell receptor repertoire in patients with coronary in-stent restenosis and type 2 diabetes

Type 2 diabetes mellitus (T2DM) is known as a risk factor for coronary in-stent restenosis (ISR) in patients with coronary artery disease (CAD). Evidence suggests that B cells play a functional role in the progression of atherosclerotic lesions. However, the B cell receptor (BCR) repertoire in patients with ISR remains unclear. This study aims to profile the BCR repertoire in patients with coronary ISR/T2DM. A total of 21 CAD patients with or without ISR/T2DM were enrolled. PBMCs were isolated and examined for BCR repertoire profiles using DNA-seq. Our results showed that the diversity of amino acid sequences in ISR DM patients was higher than that in ISR -DM patients. The frequencies of 21 V/J paired genes differed between ISR DM and -ISR DM patients, while frequencies of 5 V/J paired genes differed between ISR DM and ISR -DM. The -ISR -DM group presented the highest clonotype overlap rate, while ISR DM patients presented the lowest overlap rate. Our study presented the BCR repertoires in patients with ISR/T2DM. The data suggested different BCR signatures between patients with ISR and T2DM. Further analysis of BCR profiles would enhance understanding of ISR.

Autoimmune diseases in patients undergoing percutaneous coronary intervention: A risk factor for in-stent restenosis?

BACKGROUND AND AIMS

Despite the relation between autoimmune diseases and increased atherosclerotic risk is established, the influence of autoimmune disorders on in-stent restenosis (ISR) after percutaneous coronary intervention (PCI) is only partly known. ISR is an aberrant reparative process mainly characterized by an increased number of vascular smooth muscle cells and excessive deposition of extracellular proteoglycans and type III collagen. Chronic inflammation, always present in autoimmune diseases, modulates the endothelial response to PCI. Aim of this review is to resume the current evidence on the association between ISR and autoimmune diseases, focusing on pathogenic mechanisms and therapeutic targets.

METHODS

We conducted a comprehensive review of the literature on the relationship between ISR and insulin-dependent diabetes mellitus (IDDM), rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), antiphospholipid-antibodies syndrome (APS), inflammatory bowel diseases (IBD), and Hashimoto's thyroiditis (HT).

RESULTS

Patients affected with IDDM, RA, SLE, APS, IBD and HT proved to face higher rates of ISR compared to the general population. The endothelial dysfunction seems the principal common pathogenic pathway for ISR and is attributed to both the immune system disorder and the systemic inflammation. Some evidence suggested that methotrexate and anti-tumor necrosis factor treatments can be effective in reducing ISR, while antibodies against vascular cell adhesion molecule-1 and intercellular adhesion molecule-1 showed to reduce neointimal hyperplasia in animal models.

CONCLUSIONS

Autoimmune diseases are a risk factor for ISR. The study of the potential cardiovascular benefits of the current therapies, mainly anti-inflammatory drugs, and the pursuit of innovative treatments appear of paramount interest.

Designing Better Cardiovascular Stent Materials - A Learning Curve

Cardiovascular stents are life-saving devices and one of the top 10 medical breakthroughs of the 21st century. Decades of research and clinical trials have taught us about the effects of material (metal or polymer), design (geometry, strut thickness, and the number of connectors), and drug-elution on vasculature mechanics, hemocompatibility, biocompatibility, and patient health. Recently developed novel bioresorbable stents are intended to overcome common issues of chronic inflammation, in-stent restenosis, and stent thrombosis associated with permanent stents, but there is still much to learn. Increased knowledge and advanced methods in material processing have led to new stent formulations aimed at improving the performance of their predecessors but often comes with potential tradeoffs. This review aims to discuss the advantages and disadvantages of stent material interactions with the host within five areas of contrasting characteristics, such as 1) metal or polymer, 2) bioresorbable or permanent, 3) drug elution or no drug elution, 4) bare or surface-modified, and 5) self-expanding or balloon-expanding perspectives, as they relate to pre-clinical and clinical outcomes and concludes with directions for future studies.

Long-term survival in patients who had CABG with or without prior coronary artery stenting

Objective

To conduct a large-scale, single-centre retrospective cohort study to understand the impact of prior percutaneous coronary intervention (PCI) on long-term survival of patients who then undergo coronary artery bypass graft (CABG).

Methods

Between 1999 and 2017, a total of 11 332 patients underwent CABG at a hospital in the UK. The patients were stratified into those who received PCI (n=1090) or no PCI (n=10 242) prior to CABG. A total of 1058 patients from each group were matched using propensity score matching. Kaplan-Meier estimates were used to assess risk-adjusted survival in patients with prior PCI. Cox proportional hazards (CoxPH) model was then used to assess the effect of prior PCI and other variables in patients undergoing CABG.

Results

The immediate postoperative outcome showed no difference in number of grafts per patients, blood transfusion, hospital stay or 30 days mortality between the groups. There was no significant difference in 5 years (90.8% vs 87.9), 10-year (76.5% vs 74.6%) and 15-year (64.4% vs 64.7%) survival between the non-PCI versus PCI groups. The Cox proportional hazards model further supports the null hypothesis as the PCI variable was found to be non-significant (CoxPH=1.03, p=0.75, CI=0.87–1.22) implying there was no difference in hazard of death for CABG patients with or without previous PCI. However, the model did yield information on the covariates that do affect the hazard of death.

Conclusion

There is no difference in 5-year, 10-year and 15-year survival between patients undergoing CABG with or without prior PCI. However, certain patient, preoperative and intraoperative risk factors were identified with high hazard of death which needs to be investigated further.

<p>The Predictive Value of Monocyte Count to High-Density Lipoprotein Cholesterol Ratio in Restenosis After Drug-Eluting Stent Implantation</p>

Background

The clinical value of monocyte count to high-density lipoprotein cholesterol ratio (MHR) in in-stent restenosis (ISR) of patients who have undergone bare metal stent implantation has been studied. However, the predictive value of MHR in ISR for patients who have undergone drug-eluting stent (DES) implantation has not been explored.

Methods

Non-ST segment elevation acute coronary syndrome (NSTE-ACS) patients who had undergone DES implantation and coronary angiography follow-up at the Beijing Shijitan Hospital, Capital Medical University, between January 1, 2008, and December 31, 2018, were retrospectively enrolled. Patients were divided into ISR and non-ISR groups depending on the follow-up coronary angiography results. Relative clinical information was recorded and analyzed. The receiver operating characteristic curve analysis was used to determine the optimum cut-off pre-procedural MHR to predict ISR.

Results

A total of 214 patients were enrolled in our study. The mean period between two coronary angiography procedures was 25.4±9.8 months. Percutaneous coronary intervention due to NSTE myocardial infarction, a bifurcation lesion, increased platelet count, and a high MHR were the independent risk factors in multivariate logistic regression analyses.

Conclusion

Our results indicated that elevated MHR is an independent and useful predictor of ISR in NSTE-ACS patients who have undergone DES implantation.

Long-term outcomes of conservative treatment and endovascular treatment in patients with symptomatic spontaneous isolated superior mesenteric artery dissection: a single-center experience

BACKGROUND

Spontaneous isolated superior mesenteric artery dissection (SISMAD) is a rare vascular disorder, and the treatment strategies remain controversial. This study aimed to compare outcomes of conservative and endovascular treatments in symptomatic patients with SISMAD.

METHODS

Forty-two consecutive SISMAD patients who were admitted to a single center between October 2009 and May 2018 were enrolled in this study. Based on their symptoms, 15 had conservative treatment, and 27 had endovascular treatment. The baseline characteristics, treatments, and follow-up results of the conservative group and endovascular group were analysed.

RESULTS

The rates of symptom relief were 93.3% in the conservative group and 96.3% in the endovascular group. The procedure-related complications in the endovascular group included one case of pseudoaneurysm formation in the left brachial artery. During the follow-up period (median 28.5 months), a higher proportion of patients in the conservative group had symptom recurrence (42.9% in the conservative group versus 4.8% in the endovascular group, p < 0.001). Four patients in the conservative group and one patient in the endovascular group had additional endovascular intervention during follow-up. Compared with the conservative group, patients in the endovascular group had statistically significantly longer symptom-free survival (p = 0.014) and a higher rate of superior mesenteric artery (SMA) remodeling (p < 0.001).

CONCLUSIONS

For symptomatic SISMAD, endovascularly treated patients had a lower rate of symptom recurrence and a higher rate of SMA remodeling in the long term. Prospective, multi-center studies are needed to confirm the long-term outcomes of both treatments.

Stent edge vascular response and in-stent geometry after aerobic exercise

The purpose of the present study was to investigate the edge vascular response in patients treated with second-generation drug-eluting stents (DES) after 3 months of aerobic exercise intervention. Thirty-two patients with significant coronary artery disease underwent percutaneous coronary intervention with DES implantation prior to randomization to aerobic interval training (AIT, 14 patients) versus moderate continuous training (MCT, 18 patients). Plaque changes were assessed using grayscale and radiofrequency intravascular ultrasound at baseline and follow-up. The main endpoints were changes in plaque burden and necrotic core content in the 5-mm proximal and distal stent edges. Plaque burden in the distal stent edges decreased significantly in both groups (AIT: − 3.3%; MCT: − 0.4%, p = 0.01 for both), and more in the AIT group (p = 0.048). Necrotic core content decreased significantly in the distal stent edges in both groups (− 2.1 mm³ in AIT, − 0.3 mm³ in MCT, p = 0.01 for both), and more in the AIT group (p = 0.03). There were no significant changes in proximal stent edges or in in-stent geometry at follow-up. In this small study of patients treated with DES implantation, 3 months of aerobic exercise training demonstrated decreased plaque burden and necrotic core content in the distal stent edges, with larger reductions in the AIT group.

Potential application of liposomal nanodevices for non-cancer diseases: an update on design, characterization and biopharmaceutical evaluation

Liposomes, lipid-based vesicular systems, have attracted major interest as a means to improve drug delivery to various organs and tissues in the human body. Recent literature highlights the benefits of liposomes for use as drug delivery systems, including encapsulating of both hydrophobic and hydrophilic cargos, passive and active targeting, enhanced drug bioavailability and therapeutic effects, reduced systemic side effects, improved cargo penetration into the target tissue and triggered contents release. Pioneering work of liposomes researchers led to introduction of long-circulating, ligand-targeted and triggered release liposomes, as well as, liposomes containing nucleic acids and vesicles containing combination of cargos. Altogether, these findings have led to widespread application of liposomes in a plethora of areas from cancer to conditions such as cardiovascular, neurologic, respiratory, skin, autoimmune and eye disorders. There are numerous review articles on the application of liposomes in treatment of cancer, which seems the primary focus, whereas other diseases also benefit from liposome-mediated treatments. Therefore, this article provides an illustrated detailed overview of liposomal formulations, in vitro characterization and their applications in different disorders other than cancer. Challenges and future directions, which must be considered to obtain the most benefit from applications of liposomes in these disorders, are discussed.

Characteristics of abnormal post-stent optical coherence tomography findings in hemodialysis patients

AIM

Clinical outcomes after percutaneous coronary intervention (PCI) in hemodialysis (HD) patients are significantly worse than those in non-HD patients. Optical coherence tomography (OCT) is a high resolution imaging modality and provides a detailed assessment of post-interventional abnormal findings that influence worse clinical outcomes. However, little is known about the abnormal post-stent OCT findings in HD patients. Therefore, in this study, we compared the abnormal post-stent OCT findings between HD and non-HD patients.

METHODS

One hundred thirty-nine consecutive OCT guided PCI (21 lesions in HD patients and 118 lesions in non-HD patients) were enrolled. We compared the post-stent OCT findings, including the edge dissections, under expansion index (minimum stent area/mean reference area), and stent eccentricity index (minimum stent diameter/maximum stent diameter) between HD and non-HD patients. We also compared the device-oriented clinical events (DoCEs) at 8 months of follow up.

RESULTS

There was a significantly higher prevalence of distal edge dissections (16.7% vs. 2.8%, P = 0.011) in HD patients. HD patients had a significantly lower under expansion index (0.76 ± 0.21 vs. 0.85 ± 0.14, P = 0.029) and stent eccentricity index (0.82 ± 0.09 vs. 0.88 ± 0.18, P = 0.018). The cumulative rate of DoCEs was significantly higher in the HD patients (23.8% vs. 5.2%, P = 0.013).

CONCLUSIONS

A higher prevalence of distal edge dissections, under expansion and stent eccentricity were detected by the detailed OCT findings in HD patients.

Capturing Endothelial Cells by Coronary Stents - From Histology to Clinical Outcomes

Introduction of drug-eluting stents (DES) in the therapy of patients with coronary artery disease resulted in the significant reduction of in-stent restenosis compared to bare-metal stent (BMS) treatment. However, the high incidence of late stent thrombosis with DES emerged as one of the safety concerns after their implantation. Enhancing stent endothelization by improved early healing and neointimal strut coverage emerged as possible solution for this late complication. Endothelial progenitor cells (EPC) capturing stents are designed to promote in situ endothelization with immobilized, antihuman, anti-CD34 antibodies attached to the luminal stent surface. Anti-CD34 antibodies target and capture EPC from circulation, which further differentiate into vascular endothelial cells and form functional endothelial layer on the stent surface. These cells are also capable of secreting pro-angiogenic factors that stimulate local endothelial cells to proliferate and migrate. Preclinical and clinical studies proved feasibility, efficacy and safety of EPC capturing stents in stable and high-risk patients with coronary artery disease. Rapid and extensive endothelization of EPC capturing stents translated into favorable profile of clinical outcomes, comparable to efficacy of BMSs and DESs. Therefore, we here present the most important results from the experimental and clinical studies that explored ECP capturing strategy to enhance endothelization, reduce the incidence of instent thrombosis and improve outcomes of patients with coronary artery disease, along with the future perspectives in this promising therapeutic approach.

Real-World Use Of Ultrathin-Strut Biodegradable Polymer-Coated Sirolimus-Eluting Stents In Patients With Coronary Artery Disease: 6-Month Clinical Outcomes

BACKGROUND

Although a number of drug-eluting stents have been developed with different design, composition, and polymers, the search for an ideal drug-eluting stent is ongoing. The Tetriflex (Sahajanand Medical Technology, Surat, India) is a newer-generation, ultrathin (60 µm) biodegradable polymer-coated sirolimus-eluting stent (SES) designed with a unique long dual Z-link on a cobalt-chromium alloy. The present registry aimed to evaluate the safety and clinical outcomes of the Tetriflex SES at 6-month post-implantation.

METHODS

This was an investigator-initiated, retrospective, multicenter, single-arm, observational registry conducted at five tertiary-care centers in India. A total of 1,269 consecutive patients with coronary artery disease who underwent implantation of at least one Tetriflex SES between March 2017 and March 2018 were included. The primary outcome was considered a composite of cardiac death, myocardial infarction and target-lesion revascularization (TLR) at 6-month follow-up. Stent thrombosis was evaluated as a safety outcome at 6-month follow-up.

RESULTS

The mean age of patients was 54.99±10.80 years. Among 1,515 lesions treated with 1,682 Tetriflex SES, 58.3% were type C lesions. Six-month follow-up was done for 1,245 of 1,269 (98.1%) patients. At 6 months, composite events had occurred in 31 (2.5%) patients, consisting of ten (0.8%) cardiac deaths, 16 (1.3%) myocardial infarctions, and five (0.4%) TLRs. Stent thrombosis was observed in seven (0.56%) cases at 6 months. A subgroup analysis between diabetic and nondiabetic patients did not reveal any statistically significant difference for clinical outcomes at 6-month follow-up.

CONCLUSION

The results of the current registry outline the safety and effectiveness of the Tetriflex SES in real-world patients, as it displayed favorable clinical outcomes at 6-month follow-up, with low incidence of TLR and stent thrombosis.

The Human-Specific and Smooth Muscle Cell-Enriched LncRNA SMILR Promotes Proliferation by Regulating Mitotic CENPF mRNA and Drives Cell-Cycle Progression Which Can Be Targeted to Limit Vascular Remodeling

RATIONALE

In response to blood vessel wall injury, aberrant proliferation of vascular smooth muscle cells (SMCs) causes pathological remodeling. However, the controlling mechanisms are not completely understood.

OBJECTIVE

We recently showed that the human long noncoding RNA, SMILR, promotes vascular SMCs proliferation by a hitherto unknown mechanism. Here, we assess the therapeutic potential of SMILR inhibition and detail the molecular mechanism of action.

METHODS AND RESULTS

We used deep RNA-sequencing of human saphenous vein SMCs stimulated with IL (interleukin)-1α and PDGF (platelet-derived growth factor)-BB with SMILR knockdown (siRNA) or overexpression (lentivirus), to identify SMILR-regulated genes. This revealed a SMILR-dependent network essential for cell cycle progression. In particular, we found using the fluorescent ubiquitination-based cell cycle indicator viral system that SMILR regulates the late mitotic phase of the cell cycle and cytokinesis with SMILR knockdown resulting in ≈10% increase in binucleated cells. SMILR pulldowns further revealed its potential molecular mechanism, which involves an interaction with the mRNA of the late mitotic protein CENPF (centromere protein F) and the regulatory Staufen1 RNA-binding protein. SMILR and this downstream axis were also found to be activated in the human ex vivo vein graft pathological model and in primary human coronary artery SMCs and atherosclerotic plaques obtained at carotid endarterectomy. Finally, to assess the therapeutic potential of SMILR, we used a novel siRNA approach in the ex vivo vein graft model (within the 30 minutes clinical time frame that would occur between harvest and implant) to assess the reduction of proliferation by EdU incorporation. SMILR knockdown led to a marked decrease in proliferation from ≈29% in controls to ≈5% with SMILR depletion.

CONCLUSIONS

Collectively, we demonstrate that SMILR is a critical mediator of vascular SMC proliferation via direct regulation of mitotic progression. Our data further reveal a potential SMILR-targeting intervention to limit atherogenesis and adverse vascular remodeling.

Screening of biopolymeric materials for cardiovascular surgery toxicity-Evaluation of their surface relief with assessment of morphological aspects of monocyte/macrophage polarization in atherosclerosis patients

The morphotypes of human macrophages (MPh) were studied in the culture on nano-structured biopolymer substrates, made from polyhydroxyalcanoates (PHAs) of five various monomer compositions, followed by the solvent evaporation. Its surface relief, which was further in direct contact with human cells in vitro, was analyzed by atomic force microscopy (AFM) and scanning electron microscopy (SEM). It was shown, that the features of the micro/nano relief depend on the monomeric composition of the polymer substrates. Monocytes (MN) of patients with atherosclerosis and cardiac ischemia, undergoing stenting and conventional anti-atherosclerotic therapy, were harvested prior and after stenting. MN were isolated and cultured, with the transformation into MPh in direct contact with biopolymer culture substrates with different monomer composition and nano-reliefs, and transformed into MPh, in comparison with the same process on standard culture plastic. Sub-populations of cells with characteristic morphology in each phenotypic class were described, and their quantitative ratios for each sample of polymers were counted as an intermediate result in the development of "smart" material for cardiovascular devices. The results obtained allow us to assume, that the processes of MPh differentiation and polarization in vitro depend not only on the features of the micro/nano relief of biopolymer substrates, but also on the initial state of MN in vivo and general response of patients.

Endovascular Treatment of Patients with Isolated Mesenteric Artery Dissection Aneurysm: Bare Stents Alone Versus Stent Assisted Coiling

OBJECTIVE

The aim was to evaluate the outcomes of endovascular treatment with bare stents alone versus stent assisted coiling in isolated mesenteric artery dissection (IMAD) aneurysms.

METHODS

Patients with an IMAD aneurysm who underwent endovascular stenting between February 2010 and February 2017 at one of three institutions were included in this study. Data regarding technical success, procedure time, symptom resolution, complications, changes in IMAD aneurysm, and stent patency were recorded.

RESULTS

A total of 38 patients (35 men) were included, 27 treated with bare stents alone and 11 treated with stent assisted coiling. Technical success was achieved in 100% of patients treated with bare stents and in 81.8% of those treated with stent assisted coiling (p = 0.078). The mean procedure times were 62.6 ± 5.3 min for treatment with bare stents and 116.4 ± 8.4 min for stent assisted coiling (p < 0.001). A total of 23 patients had persistent symptoms before stenting; all symptoms were resolved within 3.0 ± 0.7 days. No procedure related major complications occurred. Over 30.2 ± 18.1 months of follow up, complete resolution of the IMAD aneurysm was achieved in all patients; good stent patency and in stent re-stenosis were achieved in 65.8% and 34.2% patients, respectively. There were no occlusions of the stented arteries.

CONCLUSIONS

Bare stents alone and stent assisted coiling have high technical success rates and demonstrate good intermediate patency in patients with an IMAD aneurysm. Bare stents alone may serve as an alternative to stent assisted coiling for the management of IMAD aneurysm.

Nanoparticles for Detection and Treatment of Peripheral Arterial Disease

Peripheral arterial disease (PAD) is defined as a slow, progressive disorder of the lower extremity arterial vessels characterized by chronic narrowing that often results in occlusion and is associated with loss of functional capacity. Although the PAD occurrence rate is increasing in the elderly population, outcomes with current treatment strategies are suboptimal. Hence, there is an urgent need to develop new technologies that overcome limitations of traditional modalities for PAD detection and therapy. In this Review, the application of nanotechnology as a tool that bridges the gap in PAD diagnosis and therapy is in focus. Several materials including synthetic, natural, biodegradable, and biocompatible materials are used to develop nanoparticles for PAD diagnostic and/or therapeutic applications. Moreover, various recent research approaches are being explored to diagnose PAD through multimodality imaging with different nanoplatforms. Further efforts include targeted delivery of various therapeutic agents using nanostructures as carriers to treat PAD. Last, but not least, despite being a fairly new field, researchers are exploring the use of nanotheranostics for PAD detection and therapy.

Adiponectin as a potential therapeutic target for the treatment of restenosis

Restenosis is a pathologic re-narrowing of a coronary artery lesion after mechanical injury. Its pathophysiological mechanisms have not been fully elucidated at present, but are thought to include inflammation, vascular smooth muscle cell (VSMC) proliferation, and matrix remodeling, beginning with insufficient endothelium healing. Restenosis presents with angina symptoms or acute coronary syndromes and lead to a revascularization, either with coronary artery bypass or repeat percutaneous coronary intervention. Some studies have reported that hypoadiponectinemia has been an independent risk factor for the onset of acute coronary syndromes and restenosis. Accumulating evidence shows that low concentrations of adiponectin may be involved in impairing endothelium functions, inflammation, and VSMC proliferation that lead to restenosis. Preclinical studies have proven that adiponectin promotes endothelium healing, effectively inhibits inflammation, and maintains contractile phenotypes of VSMCs, indicating that it may be developed as a new therapeutic target for the treatment of restenosis.

Endothelial mimetic multifunctional surfaces fabricated via polydopamine mediated copper immobilization

Nitric oxide (NO), which is continuously released from the normal healthy endodermis cell layer of the vascular system, plays a crucial role in the stability and health maintenance of blood vessels.