Coronary restenosis: a review of mechanisms and management

The Effect of Angiotensin Receptor Blockers on In-Stent Restenosis After Stent Implantation: A Meta-Analysis

AIM

Angiotensin receptor blockers (ARBs) have been shown to inhibit restenosis in vitro and in vivo, but the evidence found in humans is inconsistent. This study aimed to evaluate the effectiveness of ARBs in preventing in-stent restenosis after percutaneous coronary intervention (PCI).

METHOD

Databases including the Cochrane Library, MEDLINE, Web of Science, EMBASE, and CNKI were searched to collect randomised controlled trials on ARBs inhibiting restenosis that were published before October 2022. A total of 1,056 patients enrolled in eight trials were included in the study.

RESULTS

The ARBs group showed lower target lesion revascularisation than the control group (RR 0.54; 95% CI 0.34-0.86; p=0.01), but the restenosis incidence between these two groups was not statistically significant (RR 0.85; 95% CI 0.65-1.11; p>0.05).

CONCLUSION

This study found that ARBs might have a potential effect on reducing target lesion revascularisation after PCI in coronary heart disease patients but has no impact on angiographic restenosis.

Effect of sequential release of sirolimus and rosuvastatin using silk fibroin microneedle to prevent intimal hyperplasia

Intimal hyperplasia (IH) is a major cause of vascular restenosis after bypass surgery, which progresses as a series of processes from the acute to chronic stage in response to endothelial damage during bypass grafting. A strategic localized drug delivery system that reflects the pathophysiology of IH and minimizes systemic side effects is necessary. In this study, the sequential release of sirolimus, a mechanistic target of rapamycin (mTOR) inhibitor, and statin, an HMG-COA inhibitor, was realized as a silk fibroin-based microneedle device in vivo. The released sirolimus in the acute stage reduced neointima (NI) and vascular fibrosis through mTOR inhibition. Furthermore, rosuvastatin, which was continuously released from the acute to chronic stage, reduced vascular stiffness and apoptosis through the inactivation of Yes-associated protein (YAP). The sequential release of sirolimus and rosuvastatin confirmed the synergistic treatment effects on vascular inflammation, VSMC proliferation, and ECM degradation remodeling through the inhibition of transforming growth factor (TGF)-beta/NF-κB pathway. These results demonstrate the therapeutic effect on preventing restenosis with sufficient vascular elasticity and significantly reduced IH in response to endothelial damage. Therefore, this study suggests a promising strategy for treating coronary artery disease through localized drug delivery of customized drug combinations.

Predictive significance and diagnostic accuracy of plasma fibrinogen levels for coronary stenting outcomes

Objective: The advancement in percutaneous transluminal coronary angioplasty (PTCA) has led to it becoming the predominant mode of revascularization. Post PTCA adverse events in the form of stent thrombosis, recurrent ischemia, unplanned revascularization, recurrent hospitalization etc. result in morbidity as well as mortality. Biomarkers predicting such outcomes can be useful in initiating more aggressive medical therapy and greater modification of risk factors. This study was undertaken to study the predictive significance of periprocedural plasma fibrinogen levels for coronary stenting outcomes. Methods: 80 patients diagnosed as either chronic stable angina (CSA), unstable angina (UA), Non ST Elevation Myocardial Infarction (NSTEMI) or late presentation ST Elevation Myocardial Infarction (STEMI) undergoing planned PTCA were included in study. Patients were evaluated for clinical history, electrocardiogram (ECG), two dimensional echocardiography (2D-echo) and cardiac biomarkers (Creatinine Phorphokinase-MB isomer (CK-MB) and Troponin I). Serum fibrinogen level was measured 24 hours prior to PTCA along with routine pre-operative investigations; and also 24 hours after coronary stenting. Patients were followed for six months. Outcome measure was taken to be freedom from cardiac related adverse events, including rehospitalisation, unplanned repeat revascularization, definite stent thrombosis, transient ischemic attack, stroke and all-cause mortality. Results:  Fibrinogen level ≥393 mg/dL, 24 hours prior to percutaneous transluminal coronary angioplasty, was associated with higher major adverse cardiac and cerebrovascular events (MACCE) rates (60%) as compared to those with fibrinogen level <393 mg/dL (3.6%).  Fibrinogen level ≥427 mg/dL 24 hours after percutaneous transluminal coronary angioplasty, was associated with higher major adverse cardiac and cerebrovascular events rates (65%) as compared to those with fibrinogen level <427 mg/dL (6.7%). Conclusion: The current study demonstrates that higher baseline and post procedural fibrinogen, is an independent predictor of 6 months major adverse cardiac and cerebrovascular events after elective percutaneous coronary intervention. Key words:  Coronary stent outcomes, major adverse cardiac and cerebrovascular events, plasma fibrinogen, stent diameter

Comparison of Drug-Coated Balloons to Bare Metal Stents in the Treatment of Symptomatic Vertebral Artery-Origin Stenosis: A Prospective Randomized Trial

OBJECTIVE

We sought to compare the angiographic and clinical outcomes of drug-coated balloon (DCB) with distal embolic protection devices (EPDs) versus bare metal stent (BMS) without EPD in the treatment of symptomatic vertebral artery origin stenosis (VAOS).

METHODS

Between January 2017 and December 2018, a prospective randomized trial was conducted involving 95 patients with symptomatic VAOS randomly assigned to treatment with DCB + EPD (n = 49) or BMS without EPD (n = 46). Target vessel restenosis (RS) >50% detected by computed tomography angiography was the primary endpoint. Technical success, clinical success, and signal intensity abnormalities on diffusion-weighted imaging within 3 days after operation were compared.

RESULTS

The 30-day technical success rate was 93.9% for DCB group versus 95.7% for the BMS group (P = 0.094). Diffusion-weighted imaging within 3 days postoperative showed asymptomatic embolization in 2 (4.1%) patients in the DCB group and 9 (19.6%) patients in the BMS group (P = 0.004). At a mean 16-month follow-up, the clinical success rate was 89.8% for the DCB group versus 91.3% (42/46) for the BMS group (P = 0.125). The RS was seen in 5/49 (10.2%) in the DCB group and 6/46 (13.0%) in the BMS group (P = 0.082). Target vessel revascularization was performed in 4 (8.7%) BMS group versus 3 (6.1%) in the DCB group (P = 0.091).

CONCLUSIONS

DCB with EPD in the treatment of symptomatic VAOS is technically feasible and safe and significantly reduced thromboembolic events on imaging when compared with BMS without EPD. There was no significant difference between the 2 groups in the rate of RS during 12 months after surgery.

Imaging Features of Complications after Coronary Interventions and Surgical Procedures

Coronary artery interventions and surgical procedures are used in the treatment of coronary artery disease and some congenital heart diseases. Cardiac and noncardiac complications can occur at variable times after these procedures, with the clinical presentation ranging from asymptomatic to devastating symptoms. Invasive coronary angiography is the reference standard modality used in the evaluation of coronary arteries, with intravascular US and optical coherence tomography providing high-resolution information regarding the vessel wall. CT is the mostly commonly used noninvasive imaging modality in the evaluation of coronary artery intervention complications and allows assessment of the stent, lumen of the stent, lumen of the coronary arteries, and extracoronary structures. MRI is limited to the evaluation of the proximal coronary arteries but allows comprehensive evaluation of the myocardium, including ischemia and infarction. The authors review the clinical symptoms and pathophysiologic and imaging features of various complications of coronary artery interventions and surgical procedures. Complications of percutaneous coronary interventions are discussed, including restenosis, thrombosis, dissection of coronary arteries or the aorta, coronary wall rupture or perforation, stent deployment failure, stent fracture, stent infection, stent migration or embolism, and reperfusion injury. Complications of several surgical procedures are reviewed, including coronary artery bypass grafting, coronary artery reimplantation procedure (for anomalous origin from opposite sinuses or the pulmonary artery or as part of surgical procedures such as arterial switching surgery and the Bentall and Cabrol procedures), coronary artery unroofing, and the Takeuchi procedure. Online supplemental material is available for this article. ^©RSNA, 2021.

Eva1a ameliorates atherosclerosis by promoting re-endothelialization of injured arteries via Rac1/Cdc42/Arpc1b

AIMS

Eva-1 homologue 1 (Eva1a) is a novel protein involved in the regulation of cardiac remodelling and plaque stability, but little is known about its role in re-endothelialization and the development of atherosclerosis (AS). Thus, in the present study, we aimed to elucidate the function of Eva1a in re-endothelialization and AS.

METHODS AND RESULTS

Wire injuries of carotid and femoral arteries were established in Eva1a-/- mice. Eva1a-deficient mice were crossed with apolipoprotein E-/- (ApoE-/-) mice to evaluate AS development and re-endothelialization of carotid artery injuries. Denudation of the carotid artery at 3, 5, and 7 days was significantly aggravated in Eva1a-/- mice. The neointima of the femoral artery at 14 and 28 days was consequently exacerbated in Eva1a-/- mice. The area of atherosclerotic lesions was increased in Eva1a-/-ApoE-/- mice. To explore the underlying mechanisms, we performed transwell, scratch migration, cell counting kit-8, and bromodeoxyuridine assays using cultured human aorta endothelial cells (HAECs), which demonstrated that EVA1A promoted HAEC migration and proliferation. Proteomics revealed that the level of actin-related protein 2/3 complex subunit 1B (Arpc1b) was decreased, while Eva1a expression was absent. Arpc1b was found to be a downstream molecule of EVA1A by small interfering RNA transfection assay. Activation of Rac1 and Cdc42 GTPases was also regulated by EVA1A.

CONCLUSION

This study provides insights into anti-atherogenesis effects of Eva1a by promoting endothelium repair. Thus, Eva1a is a promising therapeutic target for AS.

Pattern of organ remodeling in chronic non-communicable diseases is due to endogenous regulations and falls under the category of Kauffman's self-organization: A case of arterial neointimal pathology

Clinical diagnosis is based on analysis of pathologic findings that may result in perceived patterns. The same is true for diagnostic pathology: Pattern analysis is a foundation of the histopathology-based diagnostic system and, in conjunction with clinical and laboratory findings, forms a basis for the classification of diseases. Any histopathology diagnosis is based on the explicit assumption that the same diseased condition should result in formation of the same (or highly similar) morphologic patterns in different individuals; it is a standard approach in microscopic pathology, including that of non-communicable chronic diseases with organ remodeling. During fifty years of examining diseased tissues under microscopy, I keep asking the same question: Why is a similarity of patterns expected for chronic organ remodeling? For infection diseases, xenobiotic toxicity and deficiencies forming an identical pathologic pattern in different individuals is understandable and logical: The same infection, xenobiotic, or deficiency strikes the same target, which results in identical pathology. The same is true for Mendelian diseases: The same mutations lead to the same altered gene expressions and the same pathologic pattern. But why does this regularity hold true for chronic diseases with organ remodeling? Presumable causes (or risk factors) for a particular chronic disease differ in magnitude and duration between individuals, which should result in various series of transformations. Yet, mysteriously enough, pathological remodeling in a particular chronic disease always falls into a main dominating pattern, perpetuating and progressing in a similar fashion in different patients. Furthermore, some chronic diseases of different etiologies and dissimilar causes/risk factors manifest as identical or highly similar patterns of pathologic remodeling. HYPOTHESIS: I hypothesize that regulations governing a particular organ's chronic remodeling were selected in evolution as the safest response to various insults and physiologic stress conditions. This hypothesis implies that regulations directing diseased chronic remodeling always preexist but normally are controlled; this control can be disrupted by a diverse range of non-specific signals, liberating the pathway for identical pathologic remodeling. This hypothesis was tested in an analysis of arterial neointimal formation, the identical pathology occurring in different diseases and pathological conditions: graft vascular disease in organ transplantation, in-stent restenosis, peripheral arterial diseases, idiopathic intimal hyperplasia, Kawasaki disease, coronary atherosclerosis and as reaction to drugs. The hypothesis suggests that arterial intimal cells are poised between only two alternative pathways: the pathway with controlled intimal cell proliferation or the pathway where such control is disrupted, ultimately leading to the progressive neointimal pathology. By this property the arterial neointimal formation constitutes a special case of Kauffman's self-organization. This new hypothesis gives a parsimonious explanation for identical pathological patterns of arterial remodeling (neointimal formation), which occurs in diseases of different etiologies and due to dissimilar causes/risk factors, or without any etiology and causes/risk factors at all. This new hypothesis also suggests that regulation facilitating intimal cell proliferation cannot be overwritten or annulled because this feature is vital for arterial differentiation, cell renewal, and integrity. This hypothesis suggests that studying numerous, and likely interchangeable, non-specific signals that disrupt regulation controlling intimal cell proliferation is unproductive; instead, a study of the controlling regulation(s) itself should be a priority of our research.

High low-density lipoprotein cholesterol as an independent risk factor for coronary restenosis in hemodialysis patients undergoing percutaneous coronary interventions

HD patients have been reported to have a higher risk of restenosis after percutaneous coronary intervention (PCI). The aim of this study was to investigate the risk factors of coronary restenosis in HD patients. We enrolled 54 HD patients (mean age: 66.5 ± 10.1 years; 72.2% men; mean HD duration: 3.7 years), who received PCI and follow-up coronary angiography. Of the patients, 22 (40.7%) had restenosis within 3 to 12 months of PCI. Univariate logistic analysis showed low-density lipoprotein cholesterol (LDL-C)/high-density lipoprotein cholesterol (HDL-C) ratio, LDL-C, non-HDL-C, and history of major adverse cardiovascular events were significantly associated with coronary restenosis (OR]: 1.89, 1.27, 1.22, and 5.79, respectively). Multivariate analysis showed that LDL-C was significantly associated with coronary restenosis (OR: 1.43). These data suggest that LDL-C is an independent risk factor for coronary restenosis in HD patients undergoing PCI, and strict lipid management may be required.

Highly multiplexed quantitative proteomic and phosphoproteomic analyses in vascular smooth muscle cell dedifferentiation

Restenosis, re-narrowing of arterial lumen following intervention for cardiovascular disease, remains a major issue limiting the long-term therapeutic efficacy of treatment. The signaling molecules, TGFβ (transforming growth factor-beta) and Smad3, play important roles in vascular restenosis, but very little is yet known about the down-stream dynamics in global protein expression and phosphorylation. Here, we develop a highly multiplexed quantitative proteomic and phosphoproteomic strategy employing 12-plex N,N-dimethyl leucine (DiLeu) isobaric tags and The DiLeu Tool software to globally assess protein expression and phosphorylation changes in smooth muscle cells (SMCs) treated with TGFβ/Smad3 and/or SDF-1α (stromal cell-derived factor). A total of 4086 proteins were quantified in the combined dataset of proteome and phosphoproteome across 12-plex DiLeu-labeled SMC samples. 2317 localized phosphorylation sites were quantified, corresponding to 1193 phosphoproteins. TGFβ/Smad3 induced up-regulation of 40 phosphosites and down-regulation of 50 phosphosites, and TGFβ/Smad3-specific SDF-1α exclusively facilitated up-regulation of 27 phosphosites and down-regulation of 47 phosphosites. TGFβ/Smad3 inhibited the expression of contractile-associated proteins including smooth muscle myosin heavy chain, calponin, cardiac muscle alpha-actin, and smooth muscle protein 22α. Gene ontology and pathway enrichment analysis revealed that elevated TGFβ/Smad3 activated cell proliferation and TGFβ signaling pathway, sequentially stimulating phosphorylation of CXCR4 (C-X-C chemokine receptor 4). SDF-1α/CXCR4 activated extracellular signal-regulating kinase signaling pathway and facilitated the expression of synthetic marker, osteopontin, which was validated through targeted analysis. These findings provide new insights into the mechanisms of TGFβ regulated SMC dedifferentiation, as well as new avenues for designing effective therapeutics for vascular disease.

Increase of wall shear stress caused by arteriovenous fistula reduces neointimal hyperplasia after stent implantation in healthy arteries

BACKGROUND AND OBJECTIVES

Wall shear stress plays a critical role in neointimal hyperplasia after stent implantation. It has been found that there is an inverse relation between wall shear stress and neointimal hyperplasia. This study hypothesized that the increase of arterial wall shear stress caused by arteriovenous fistula could reduce neointimal hyperplasia after stents implantation.

METHODS AND RESULTS

Thirty-six male rabbits were randomly divided into three groups: STENT, rabbits received stent implantation into right common carotid artery; STENT/arteriovenous fistula, rabbits received stent implantation into right common carotid artery and carotid-jugular arteriovenous fistula; Control, rabbits received no treatment. After 21 days, stented common carotid artery specimens were harvested for histological staining and protein expression analysis. In STENT group, wall shear stress maintained at a low level from 43.2 to 48.9% of baseline. In STENT/arteriovenous fistula group, wall shear stress gradually increased to 86% over baseline. There was a more significant neointimal hyperplasia in group STENT compared with the STENT/arteriovenous fistula group (neointima area: 0.87 mm² versus 0.19 mm²; neointima-to-media area ratio: 1.13 versus 0.18). Western blot analysis demonstrated that the protein level of endothelial nitric oxide synthase in STENT group was significantly lower than that in STENT/arteriovenous fistula group, but the protein levels of proliferating cell nuclear antigen, vascular cell adhesion molecule 1, phospho-p38 mitogen-activated protein kinase (Pp38), and phospho-c-Jun N-terminal kinase in STENT group were significantly higher than that in the STENT group.

CONCLUSION

High wall shear stress caused by arteriovenous fistula as associated with the induction in neointimal hyperplasia after stent implantation. The underlying mechanisms may be related to modulating the expression and activation of endothelial nitric oxide synthase, vascular cell adhesion molecule 1, p38, and c-Jun N-terminal kinase.

Co-immobilization of ACH11 antithrombotic peptide and CAG cell-adhesive peptide onto vascular grafts for improved hemocompatibility and endothelialization

Surface modification by conjugating biomolecules has been widely proved to enhance biocompatibility of small-caliber artificial vascular grafts. In this study, we aimed at developing a multifunctional vascular graft that provides not only good hemocompatibility but also in situ rapid endothelialization. Herein, a vascular graft (inner diameter ∼2 mm) was fabricated by electrospinning with poly(lactic acid-co-caprolactone) and gelatin, and then biofunctionalized with antithrombotic peptide with sequence LTFPRIVFVLG (ACH₁₁) and cell adhesion peptide with sequence CAG through adhesive poly(dopamine) coating. We developed this graft with the synergistic properties of low thrombogenicity and rapid endothelialization. The successful grafting of both CAG and ACH₁₁ peptides was confirmed by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. The surface micromorphology of the modified surfaces was observed by field emission scanning electron microscopy. Our results demonstrated that the multifunctional surface suppressed the denaturation of absorbed fibrinogen, hindered coagulation factor Xa activation, and inhibited platelet adhesion and aggregation. Importantly, this modified surface could selectively enhance endothelial cells adhesion, proliferation and release of nitric oxide. Upon in vivo implantation of 6 weeks, the multifunctional vascular graft showed improved patency and superior vascular endothelialization. Overall, the results effectively demonstrated that the co-immobilization of ACH₁₁ and CAG provided a promising method for the improvement of hemocompatibility and endothelialization of vascular grafts. STATEMENT OF SIGNIFICANCE: Electrospun small-caliber vascular grafts are increasingly used to treat cardiovascular diseases. Despite their success related to their good biodegradation and mechanical strength, they have some drawbacks, such as low hemocompatibility and endothelialization. The single-function ligands are insufficient to modify surface with both good hemocompatibility and rapid endothelialization simultaneously. Therefore, we functionalized electrospun vascular graft by novel antithrombotic peptide and cell-adhesive peptide to construct superior anticoagulation and ECs-selective adhesion surface in present study. The multifunctional vascular grafts benefit for high long-term patency and rapid endothelialization.

Plasma osteopontin concentration is elevated in patients with coronary bare metal stent restenosis

OBJECTIVE

Osteopontin is a component of atherosclerotic lesions, secreted by monocytes, macrophages and endothelial and vascular smooth muscle cells, which together are responsible for neointimal proliferation. We examined whether elevated plasma osteopontin concentration was associated with in-stent restenosis in patients with coronary artery disease.

SUBJECTS AND METHODS

We enrolled 91 patients who underwent coronary artery stenting, and 60 control patients with normal findings on coronary angiography, between June 2012 and September 2013. For patients with stents, we measured plasma osteopontin concentration at the first follow-up coronary angiogram. For controls, plasma osteopontin concentration was measured at the time of angiography.

RESULTS

Of the 91 patients who had undergone coronary artery stenting, 31 (34.1%) had developed in-stent restenosis and the mean time passed to control coronary angiography was 36.7 months (±SD 35.1 months). Mean plasma osteopontin concentration in this group was 2721.4 ± 1787.8 pg/ml, significantly higher than the 60 patients (65.9%) with no in-stent restenosis (1770.4 ± 1208.2 pg/ml, p = .011) and the 60 patients with a normal coronary angiogram (1572.4 ± 904.8 pg/ml, p = .002). There was no significant difference in mean osteopontin concentration between the patients with no in-stent restenosis and the control group (p = .312).

CONCLUSIONS

Elevated plasma osteopontin concentration is associated with in-stent stenosis in patients with coronary artery disease. Further studies will be needed to establish whether osteopontin can predict in-stent restenosis and guide clinical management strategies.

Radiation suppresses neointimal hyperplasia through affecting proliferation and apoptosis of vascular smooth muscle cells

PURPOSE

To study the effect of x-ray radiotherapy on vascular smooth muscle cells (VSMCs) and elucidate the mechanisms in preventing neointimal hyperplasia of prosthetic vascular grafts.

MATERIALS AND METHODS

In model I, twelve mongrel dogs underwent revascularization with prosthetic grafts and half the dogs underwent irradiation of the grafts at 28 Gy. In model II, human VSMCs (hVSMCs) were maintained and divided into six groups to which external radiation was applied at six different doses: 0 Gy, 2 Gy, 8 Gy, 16 Gy, 24 Gy and 30 Gy. In both models, specimens were harvested and examined by using morphological, immunological, cellular and molecular methods.

RESULTS

After irradiation, the neointima thickness was significantly lower in irradiated groups (p≤0.01). The radiotherapy could up-regulate p27^kip1, and down-regulate proliferating cell nuclear antigen (PCNA) and S phase kinase associated protein 2 (Skp2). X-ray irradiation inhibits the proliferation of hVSMCs via acting on G1/S phase of cell cycle. The apoptosis of hVSMCs increased significantly with dose and time. The expression of PCNA and Skp2 were decreased after a first increasing trend with dose, but had a significant negative correlation with time. The expression of p27^kip1 had a significant positive correlation with dose and time.

CONCLUSIONS

Postoperative external fractionated irradiation after prosthetic vessel replacement of the abdominal aorta suppressed the development of hyperplasia in the graft neointima in the short term. There was a prominent time- and dose-dependent inhibition of VSMC proliferation by radiation when it was administered.

Application of galangin, an active component of Alpinia officinarum Hance (Zingiberaceae), for use in drug-eluting stents

In clinical pathology, stent interposition is used to treat vascular disease but can lead to restenosis. Drug-eluting stents (DES) are most commonly used to suppress restenosis but can also have side effects. Therefore, we investigated the anti-proliferative effect and its possible target in vitro and in vivo. We found that Alpinia officinarum Hance (AO) extract efficiently inhibited VSMC proliferation by arresting the transition from the G₀/G₁ to the S phase via the up-regulation of p27^KIP1 expression. Galangin (GA) was determined to be a significant component of this extract, with the same anti-proliferative activity as the raw extract. Immunoblotting and immunofluorescence staining showed that both the AO extract and GA targeted the up-regulation of p27^KIP1 expression. Therefore, we next examined the effect of these compounds in a cuff-injured neointimal hyperplasia model in vivo. In this animal model, both the AO extract and GA completely suppressed the neointima formation, and this inhibitory effect was also demonstrated to target the up-regulation of p27^KIP1, including the suppression of proliferating cell nuclear antigen expression. Our findings indicate that AO extract and GA have a potent anti-proliferative activity, targeting the up-regulation of p27 expression. Thus, GA may represent an alternative medicine for use in DES.

A Cytokine-Like Protein Dickkopf-Related Protein 3 Is Atheroprotective

Supplemental Digital Content is available in the text.

Background:

Dickkopf-related protein 3 (DKK3) is a secreted protein that is involved in the regulation of cardiac remodeling and vascular smooth muscle cell differentiation, but little is known about its role in atherosclerosis.

Methods:

We tested the hypothesis that DKK3 is atheroprotective using both epidemiological and experimental approaches. Blood DKK3 levels were measured in the Bruneck Study in 2000 (n=684) and then in 2005 (n=574). DKK3-deficient mice were crossed with apolipoprotein E^-/- mice to evaluate atherosclerosis development and vessel injury-induced neointimal formation. Endothelial cell migration and the underlying mechanisms were studied using in vitro cell culture models.

Results:

In the prospective population-based Bruneck Study, the level of plasma DKK3 was inversely related to carotid artery intima-media thickness and 5-year progression of carotid atherosclerosis independently from standard risk factors for atherosclerosis. Experimentally, we analyzed the area of atherosclerotic lesions, femoral artery injury-induced reendothelialization, and neointima formation in both DKK3^-/-/apolipoprotein E^-/- and DKK3^+/+/apolipoprotein E^-/- mice. It was demonstrated that DKK3 deficiency accelerated atherosclerosis and delayed reendothelialization with consequently exacerbated neointima formation. To explore the underlying mechanisms, we performed transwell and scratch migration assays using cultured human endothelial cells, which exhibited a significant induction in cell migration in response to DKK3 stimulation. This DKK3-induced migration activated ROR2 and DVL1, activated Rac1 GTPases, and upregulated JNK and c-jun phosphorylation in endothelial cells. Knockdown of the ROR2 receptor using specific siRNA or transfection of a dominant-negative form of Rac1 in endothelial cells markedly inhibited cell migration and downstream JNK and c-jun phosphorylation.

Conclusions:

This study provides the evidence for a role of DKK3 in the protection against atherosclerosis involving endothelial migration and repair, with great therapeutic potential implications against atherosclerosis.

Use of Micropatterned Thin Film Nitinol in Carotid Stents to Augment Embolic Protection

Stenting is an alternative to endarterectomy for the treatment of carotid artery stenosis. However, stenting is associated with a higher risk of procedural stroke secondary to distal thromboembolism. Hybrid stents with a micromesh layer have been proposed to address this complication. We developed a micropatterned thin film nitinol (M-TFN) covered stent designed to prevent thromboembolism during carotid intervention. This innovation may obviate the need or work synergistically with embolic protection devices. The proposed double layered stent is low-profile, thromboresistant, and covered with a M-TFN that can be fabricated with fenestrations of varying geometries and sizes. The M-TFN was created in multiple geometries, dimensions, and porosities by sputter deposition. The efficiency of various M-TFN to capture embolic particles was evaluated in different atherosclerotic carotid stenotic conditions through in vitro tests. The covered stent prevented emboli dislodgement in the range of 70%–96% during 30 min duration tests. In vitro vascular cell growth study results showed that endothelial cell elongation, alignment and growth behaviour silhouettes significantly enhance, specifically on the diamond-shape M-TFN, with the dimensions of 145 µm × 20 µm and a porosity of 32%. Future studies will require in vivo testing. Our results demonstrate that M-TFN has a promising potential for carotid artery stenting.

Blood level of CD45+ platelets and development of restenosis after drug-eluting stent implantation in patients with stable coronary artery disease

OBJECTIVE

The aim of this study was to assess CD45-positive platelets (CD45+ platelets) involvement in restenosis development after drug-eluting stent (DES) implantation in patients with stable coronary artery disease (CAD).

METHODS

The study comprised 126 male and female patients with stable angina pectoris, who underwent elective coronary stenting with DES and follow-up angiography within 6-12 months. The patients were assigned to the group with restenosis (n = 53) or group without restenosis (n = 73) according to the follow-up angiograms. In both groups we compared the level in blood of CD45+ platelets, the clinical, laboratory and angiographic variables, which may affect the development of restenosis. We have also constructed a logit regression model for prognosis of restenosis occurrence after DES implantation.

RESULTS

The blood count of CD45+ platelets was higher in patients with restenosis than in patients without: 0.82 % (0.58; 1.12) vs. 0.34 % (0.20; 0.68), p < 0.001, data are expressed as median (lower quartile; upper quartile). By binary comparisons of more than 35 different clinical, laboratory and angiographic variables we identified 8 significant risk factors for the development of stent restenosis after DES. In order to define the risk of the development of restenosis, we have built a logit regression model. The resulting logit regression equation included the level of CD45+ platelets, the neutrophil to lymphocyte ratio (NLR), small diameter arteries stenting and the number of simultaneously implanted stents in one patient. Receiver operating characteristic (ROC) curve analysis has demonstrated the high prognostic value of the resulting logit regression equation with an area under the curve (AUC) of 0.91 % (p < 0.001).

CONCLUSIONS

The acquired data indicate the presence of a close relationship between circulating CD45+ platelets and restenosis development after DES implantation in patients with stable CAD.

Association between Proliferative Scars and In-Stent Restenosis

Background:

Keloid and hypertrophic scars are two types of proliferative scars at sites of cutaneous injury that form as a result of an abnormal wound-healing process. Proliferative scar formation after skin injury and restenosis after coronary stenting have common features. The aim of this study was to investigate the association of proliferative scars with coronary stent restenosis.

Methods:

Patients with previous open heart surgery with median sternotomy who had coronary stenting after the surgery and were admitted for control angiography were included in the study. The patients were divided into two groups according to the presence or absence of proliferative scars. The primary end point was the incidence of angiographic restenosis in patient groups.

Results:

The study group consisted of 80 patients (64 men; mean age 64 ± 9 years). Twenty-three patients (29%) have a proliferative scar. In general, two groups were comparable with regard to baseline lipid profiles, demographics, and cardiovascular risk factors. Restenosis was significantly more prevalent in patients with proliferative scars than with controls ( p = .04). By multivariate logistic regression analysis, stent length (odds ratio [OR] 1.12, p = .005), diabetes (OR 3.3, p = .03), and proliferative scar (OR 4.2, p = .02) independently predicted in-stent restenosis.

Conclusion:

The findings of this study suggest that patients with proliferative scars may have a higher risk of in-stent restenosis.

High-Throughput RNAi Screening Identifies a Role for the Osteopontin Pathway in Proliferation and Migration of Human Aortic Smooth Muscle Cells

PURPOSE

Understanding of the mechanisms of vascular smooth muscle cells (VSMCs) phenotypic regulation is critically important to identify novel candidates for future therapeutic intervention. While HTS approaches have recently been used to identify novel regulators in many cell lines, such as cancer cells and hematopoietic stem cells, no studies have so far systematically investigated the effect of gene inactivation on VSMCs with respect to cell survival and growth response.

METHODS AND RESULTS

257 out of 2000 genes tested resulted in an inhibition of cell proliferation in HaoSMCs. After pathway analysis, 38 significant genes were selected for further study. 23 genes were confirmed to inhibit proliferation, and 13 genes found to induce apoptosis in the synthetic phenotype. 11 genes led to an aberrant nuclear phenotype indicating a central role in cell mitosis. 4 genes affected the cell migration in synthetic HaoSMCs. Using computational biological network analysis, 11 genes were identified to have an indirect or direct interaction with the Osteopontin pathway. For 10 of those genes, levels of proteins downstream of the Osteopontin pathway were found to be down-regulated, using RNAi methodology.

CONCLUSIONS

A phenotypic high-throughput siRNA screen could be applied to identify genes relevant for the cell biology of HaoSMCs. Novel genes were identified which play a role in proliferation, apoptosis, mitosis and migration of HaoSMCs. These may represent potential drug candidates in the future.

Nitinol-Based Nanotubular Arrays with Controlled Diameters Upregulate Human Vascular Cell ECM Production

Current approaches to reducing restenosis do not balance the reduction of vascular smooth muscle cell proliferation with the increase in the healing of the endothelium. Building on our previous work, we present our study on the effects of Nitinol-based nanotubular coatings with different nanotube diameters on the reduction of restenosis. Here, we demonstrate that the nanotubular coatings reduced primary human aortic smooth muscle cell (HASMC) proliferation and increased the migration (by more than 4 times), collagen (by 2-3 times per cell) and elastin (by 5-8 times per cell) production of primary human aortic endothelial cells (HAEC). Furthermore, a significant increase in elastin and soluble collagen production of HAEC was observed with an increase in nanotube diameter. Our findings suggest that nanotubes-coated Nitinol may provide a surface conducive for HAEC reendothelialization while reducing the proliferation of HASMC.

Tong-xin-luo capsule for patients with coronary heart disease after percutaneous coronary intervention

BACKGROUND

Percutaneous coronary intervention (PCI) is a standard treatment for coronary heart disease (CHD). Restenosis, defined as a 50% reduction in luminal diameter at six months after PCI, indicates a need for revascularisation. Restenosis has proven to be a major drawback to PCI. Tong-xin-luo is one of the prophylactic strategies for cardiovascular events in patients after PCI that is widely used in China, but its efficacy and safety have not been systematically evaluated.

OBJECTIVES

To systematically assess the efficacy and safety of Tong-xin-luo capsules in preventing cardiovascular events after PCI in patients with CHD.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials in The Cochrane Library, MEDLINE (OVID), EMBASE (OVID), WanFang, Chinese Biomedical Database, Chinese Medical Current Contents, and China National Knowledge Infrastructure from their inception to June 2014. We also searched other resources, including ongoing trials and research registries. We applied no language restrictions.

SELECTION CRITERIA

Randomised controlled trials of participants with CHD after PCI were included. Participants in the intervention group received Tong-xin-luo capsules for at least three months.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data and assessed the risk of bias. Any disagreements were resolved by discussion with a third review author. The primary outcomes included occurrence of angiographic restenosis and adverse events; the secondary outcomes included myocardial infarction, heart failure, angina, all cause mortality, mortality due to any cardiovascular event, use of revascularisation, patient acceptability, quality of life and cost-effectiveness. Dichotomous data were measured with risk ratios (RRs) with 95% confidence intervals (CIs).

MAIN RESULTS

Sixteen studies involving 1063 participants were identified. The risk of bias for fifteen studies was high and along with imprecision and possible publication bias, this lowered our confidence in the results. There was low quality evidence that Tong-xi-luo reduced the rates of angiographic restenosis (RR 0.16, 95% CI 0.07 to 0.34), myocardial infarction (RR 0.32, 95% CI 0.16 to 0.66), heart failure (RR 0.26, 95% CI 0.11 to 0.62), and use of revascularisation (RR 0.26, 95% CI 0.15 to 0.45). There was very low quality evidence for the effect of Tong-xin-luo on all-cause mortality (RR 0.38, 95% CI 0.06 to 2.56), angina (RR 0.24, 95% CI 0.17 to 0.34) and death due to any cardiovascular event (RR 0.31, 95% CI 0.08 to 1.12). Adverse events were seldom reported, and included gastrointestinal reactions and nausea.

AUTHORS' CONCLUSIONS

The addition of Tong-xin-luo to conventional Western medicine may possibly prevent restenosis and recurrence of cardiovascular events in patients with CHD after PCI. However, the data are limited by publication bias and high risk of bias for included studies. Further high-quality trials are required to evaluate the potential effects of this intervention.

Relationship between histologic features and outcomes of carotid revascularization for radiation-induced stenosis

OBJECTIVE

This study aimed to elucidate the relationships between preoperative carotid imaging results, histologic characteristics, and surgical treatment outcomes of radiation-induced carotid stenosis (RICS), using control subjects without RICS for comparison.

METHODS

We retrospectively reviewed records of 17 patients who underwent carotid revascularization for 22 instances of RICS, including 10 cases of carotid artery stenting (CAS), 11 cases of carotid endarterectomy (CEA), and 1 case of CEA with retrograde CAS, between July 2004 and April 2013. The controls were 475 patients with no history of radiation therapy who underwent carotid revascularization in a similar period. Preoperative magnetic resonance imaging (MRI), ultrasonography (US), and computed tomography angiography results were correlated with outcomes of histologic analysis of CEA specimens. End points included ipsilateral and contralateral stroke, myocardial infarction, restenosis, in-stent thrombosis, and target lesion revascularization.

RESULTS

Vulnerable plaques on carotid MRI (86% vs 64.2%; P = .010) and mobile (27% vs 8.0%; P = .008) and ulcerative (50% vs 15.8%; P < .001) plaques on US were more frequent in the RICS group. All revascularization procedures were successful, and no occlusion occurred. Adverse events in the CAS group, including one minor stroke and one transient ischemic attack within 30 days as well as five ipsilateral neurologic events after 30 days, including three minor strokes and two transient ischemic attacks, were significantly more frequent than in the CEA group. All three cases of late ipsilateral stroke displayed vulnerable plaque on preoperative MRI and late in-stent thrombosis or restenosis on US.

CONCLUSIONS

Our radiologic and histologic analyses revealed that advanced RICS is often accompanied by formation of vulnerable plaque. CEA can prevent undesirable late outcomes in such cases.

Nitinol-based nanotubular coatings for the modulation of human vascular cell function

In this study, we describe the synthesis of an upright nanotubular coating with discrete, exposed nanotubes on top of superelastic Nitinol via anodization and characterization of the surface elemental composition and nickel release rates. We demonstrate, for the first time, that this coating could improve re-endothelialization by increasing the cell spreading and migration of primary human aortic endothelial cells on Nitinol. We also show the potential for reducing neointimal hyperplasia by decreasing the proliferation and expression of collagen I and MMP-2 in primary human aortic smooth muscle cells (HASMC). Furthermore, we did not observe the nanotubular surface to induce inflammation through ICAM-1 expression in HASMC as compared to the flat control. This coating could be used to improve Nitinol stents by reducing restenosis rates and, given the extensive use of Nitinol in other implantable devices, act as a generalized coating strategy for other medical devices.

Mussel-inspired one-step adherent coating rich in amine groups for covalent immobilization of heparin: hemocompatibility, growth behaviors of vascular cells, and tissue response

Heparin, an important polysaccharide, has been widely used for coatings of cardiovascular devices because of its multiple biological functions including anticoagulation and inhibition of intimal hyperplasia. In this study, surface heparinization of a commonly used 316L stainless steel (SS) was explored for preparation of a multifunctional vascular stent. Dip-coating of the stents in an aqueous solution of dopamine and hexamethylendiamine (HD) (PDAM/HD) was presented as a facile method to form an adhesive coating rich in primary amine groups, which was used for covalent heparin immobilization via active ester chemistry. A heparin grafting density of about 900 ng/cm(2) was achieved with this method. The retained bioactivity of the immobilized heparin was confirmed by a remarkable prolongation of the activated partial thromboplastin time (APTT) for about 15 s, suppression of platelet adhesion, and prevention of the denaturation of adsorbed fibrinogen. The Hep-PDAM/HD also presented a favorable microenvironment for selectively enhancing endothelial cell (EC) adhesion, proliferation, migration and release of nitric oxide (NO), and at the same time inhibiting smooth muscle cell (SMC) adhesion and proliferation. Upon subcutaneous implantation, the Hep-PDAM/HD exhibited mitigated tissue response, with thinner fibrous capsule and less granulation formation compared to the control 316L SS. This number of unique functions qualifies the heparinized coating as an attractive alternative for the design of a new generation of stents.

Gallic acid tailoring surface functionalities of plasma-polymerized allylamine-coated 316L SS to selectively direct vascular endothelial and smooth muscle cell fate for enhanced endothelialization

The creation of a platform for enhanced vascular endothelia cell (VEC) growth while suppressing vascular smooth muscle cell (VSMC) proliferation offers possibility for advanced coatings of vascular stents. Gallic acid (GA), a chemically unique phenolic acid with important biological functions, presents benefits to the cardiovascular disease therapy because of its superior antioxidant effect and a selectivity to support the growth of ECs more than SMCs. In this study, GA was explored to tailor such a multifunctional stent surface combined with plasma polymerization technique. On the basis of the chemical coupling reaction, GA was bound to an amine-group-rich plasma-polymerized allylamine (PPAam) coating. The GA-functionalized PPAam (GA-PPAam) surface created a favorable microenvironment to obtain high ECs and SMCs selectivity. The GA-PPAam coating showed remarkable enhancement in the adhesion, viability, proliferation, migration, and release of nitric oxide (NO) of human umbilical vein endothelial cells (HUVECs). The GA-PPAam coating also resulted in remarkable inhibition effect on human umbilical artery smooth muscle cell (HUASMC) adhesion and proliferation. These striking findings may provide a guide for designing the new generation of multifunctional vascular devices.

Blood flow and stem cells in vascular disease

It is well known that the altered blood flow is related to vascular diseases, including atherosclerosis, restenosis, and arteriosclerosis, which preferentially located at areas with the disturbed blood flow, suggesting that altered biomechanical stress may exert their effect on the vascular disease. Recent evidence indicated the presence of abundant stem/progenitor cells in the vessel wall, in which laminar shear stress can stimulate these cells to differentiate towards endothelial lineage, while cyclic strain results in smooth muscle differentiation. In line with this, it was evidenced that altered biomechanical stress in stented vessels may lead to 'wrong' direction of vascular stem cell differentiation resulting in restenosis. However, the underlying mechanisms are not well understood. In this article, we will give an overview of the effect of the local flow pattern on stem/progenitor cell differentiation and the possible mechanism on how the blood flow influences stem cell behaviours in the development of vascular diseases.

Bioactive coronary stent coating based on layer-by-layer technology for siRNA release

One procedure to treat stenotic coronary arteries is the percutaneous transluminal coronary angioplasty (PTCA). In recent years, drug-eluting stents (DESs) have demonstrated elaborate ways to improve outcomes of intravascular interventions. To enhance DESs, the idea has evolved to design stents that elute specific small interfering RNA (siRNA) for better vascular wall regeneration. Layer-by-layer (LbL) technology offers the possibility of incorporating siRNA nanoplexes (NPs) to achieve bioactive medical implant coatings. The LbL technique was used to achieve hyaluronic acid/chitosan (HA/Chi) films with incorporated Chi-siRNA NPs. The multilayer growth was monitored by quartz crystal microbalance. The coating on the stents and its thickness were analyzed using fluorescence and scanning electron microscopy. All stents showed a homogeneous coating, and the polyelectrolyte multilayers (PEMs) were not disrupted after ethylene oxide sterilization or expansion. The in vitro uptake of fluorescent-labeled NPs from PEMs in primary human endothelial cells (ECs) was analyzed by flow cytometry for 2, 6 and 9 days. Furthermore, stents coated with HA/Chi and Chi-siRNA NPs were expanded into porcine arteries and showed ex vivo delivery of NPs. The films showed no critical results in terms of hemocompatibility. This study demonstrates that Chi-siRNA NPs can be incorporated into PEMs consisting of HA and Chi. We conclude that the NPs were delivered to ECs under in vitro conditions. Furthermore, under ex vivo conditions, NPs were transferred into porcine artery walls. Due to their good hemocompatibility, they might make an innovative tool for achieving bioactive coatings for coronary stents.

Impact of metabolic syndrome on re-stenosis development: role of drug-eluting stents

Metabolic syndrome (MetS) is defined as a cluster of numerous cardiovascular risk factors, which encompasses obesity, dyslipidaemia, insulin resistance and hypertension. Patients with MetS are more prone to developing cardiovascular events than other patients. To date, several approaches such as physical exercise, dietary control and invasive and non-invasive therapeutic interventions for dyslipidaemia, hypertension and insulin resistance have been used to manage MetS. However, there is a progressive elevation in the incidence of fatal and non-fatal cardiovascular events due to the increased prevalence of obesity and diabetes. Percutaneous coronary intervention has emerged over the last few years as an effective revascularisation strategy for those with coronary artery disease, in parallel with the development of effective anti-platelet medications and newer drug-eluting stents. In recent years, considerable research efforts have been undertaken to elucidate the pathophysiology of re-stenosis and develop strategies to prevent re-stenosis following percutaneous transluminal coronary angioplasty and stent implantation. Although the rate of stent re-stenosis and target-lesion revascularisation has been reduced, there is little information in the literature on the outcome of MetS in the pathophysiology of re-stenosis. In this review article, we summarise the recent development and progress on re-stenosis and the role of drug-eluting stents, particularly in MetS.

MAPK phosphorylation of connexin 43 promotes binding of cyclin E and smooth muscle cell proliferation

RATIONALE

Dedifferentiation of vascular smooth muscle cells (VSMC) leading to a proliferative cell phenotype significantly contributes to the development of atherosclerosis. Mitogen-activated protein kinase (MAPK) phosphorylation of proteins including connexin 43 (Cx43) has been associated with VSMC proliferation in atherosclerosis.

OBJECTIVE

To investigate whether MAPK phosphorylation of Cx43 is directly involved in VSMC proliferation.

METHODS AND RESULTS

We show in vivo that MAPK-phosphorylated Cx43 forms complexes with the cell cycle control proteins cyclin E and cyclin-dependent kinase 2 (CDK2) in carotids of apolipoprotein-E receptor null (ApoE(-/-)) mice and in C57Bl/6 mice treated with platelet-derived growth factor-BB (PDGF). We tested the involvement of Cx43 MAPK phosphorylation in vitro using constructs for full-length Cx43 (Cx43) or the Cx43 C-terminus (Cx43(CT)) and produced null phosphorylation Ser>Ala (Cx43(MK4A)/Cx43(CTMK4A)) and phospho-mimetic Ser>Asp (Cx43(MK4D)/Cx43(CTMK4D)) mutations. Coimmunoprecipitation studies in primary VSMC isolated from Cx43 wild-type (Cx43(+/+)) and Cx43 null (Cx43(-/-)) mice and analytic size exclusion studies of purified proteins identify that interactions between cyclin E and Cx43 requires Cx43 MAPK phosphorylation. We further demonstrate that Cx43 MAPK phosphorylation is required for PDGF-mediated VSMC proliferation. Finally, using a novel knock-in mouse containing Cx43-MK4A mutation, we show in vivo that interactions between Cx43 and cyclin E are lost and VSMC proliferation does not occur after treatment of carotids with PDGF and that neointima formation is significantly reduced in carotids after injury.

CONCLUSIONS

We identify MAPK-phosphorylated Cx43 as a novel interacting partner of cyclin E in VSMC and show that this interaction is critical for VSMC proliferation. This novel interaction may be important in the development of atherosclerotic lesions.

Dexamethasone-incorporated nanofibrous meshes for antiproliferation of smooth muscle cells: thermally induced drug-loading strategy

Pluronic-immobilized nanofibrous meshes were tailored for thermally induced incorporation of dexamethasone. A diblock copolymer composed of poly(e-caprolactone)-poly (ethyleneglycol) (NH(2)) (PCL-PEG (NH(2))) was electrospun to a nanofibrous mesh, and Pluronic was subsequently surface-immobilized on the mesh in aqueous phase. Surface-wettability analysis and (1)H NMR spectroscopy confirmed surface-decoration of nanofibrous meshes with Pluronic moieties depending on the blend ratios of PCL-PEG(NH(2)). Fluorescently-labeled micelles were incorporated in the nanofibrous meshes by temperature modulation and showed attenuated release profiles of the micelles were for 1 month. The suppression degree of drug-loaded micelle releases was proportional to the blend ratio of PCL-PEG(NH(2)). Dexamethasone was formulated into micellar nanoaggregates, and the dexamethasone micelles-loaded nanofibrous meshes were used for antiproliferation studies of smooth muscle cells. Flow cytometric analysis of the arrested cells at a G(0)-G(1) phase revealed that the dexamethasone micelles-loaded nanofibrous meshes effectively controlled proliferation of the smooth muscle cells when cells were cultivated with the nanofibrous meshes. The antiproliferation effects of the nanofibrous meshes were closely correlated to the release profiles of the micelles from the nanofibrous meshes with different blend ratios. Thus, dexamethasone-incorporated nanofibrous meshes can be potentially used for treatments of restenosis after percutaneous transluminal coronary angioplasty.

Paclitaxel and sirolimus differentially affect growth and motility of endothelial progenitor cells and coronary artery smooth muscle cells

AIMS

EPC and hCASMC play an important role in the pathogenesis of restenosis and stent thrombosis. Drug-coated balloon catheters exert a local, short-term application of antiproliferative agents. This study investigates the time-dependent influence on growth and motility of paclitaxel and sirolimus alone and combined with the coating additive iopromide on EPC and hCASMC.

METHODS AND RESULTS

Treatment of cultured human EPC and hCASMC with paclitaxel and sirolimus 1.5 and 15 µM for three seconds, three minutes and 24 hours, alone or combined with iopromide 0.197 M, resulted in a concentration- and time- dependent inhibition of proliferation and of migration. Paclitaxel and sirolimus increase apoptosis in either cell type. However, the effects of paclitaxel and sirolimus differed between the cell types: short-term exposure with paclitaxel leads to stronger inhibition of cell-density and apoptosis of hCASMC compared to EPC. In comparison to paclitaxel, short-term incubation with sirolimus showed a more effective inhibition of cell-density and migration as well as increased apoptosis in EPC in contrast to hCASMC. The effects of paclitaxel and sirolimus were increased in combination with iopromide. Interestingly, the antiproliferative effect of the paclitaxel-iopromide formulation on hCASMC was more potent compared to its effect on EPC. Endothelialisation in a porcine coronary stent model was similar with drug-coated balloons and uncoated controls, whereas it was delayed with drug-eluting stents.

CONCLUSION

After short-term application, paclitaxel and sirolimus show differential, cell-specific effects on EPC and hCASMC. Iopromide used as a coating agent intensifies these effects.

A genome-wide association study identifies a region at chromosome 12 as a potential susceptibility locus for restenosis after percutaneous coronary intervention

Percutaneous coronary intervention (PCI) has become an effective therapy to treat obstructive coronary artery diseases (CAD). However, one of the major drawbacks of PCI is the occurrence of restenosis in 5-25% of all initially treated patients. Restenosis is defined as the re-narrowing of the lumen of the blood vessel, resulting in renewed symptoms and the need for repeated intervention. To identify genetic variants that are associated with restenosis, a genome-wide association study (GWAS) was conducted in 295 patients who developed restenosis (cases) and 571 who did not (controls) from the GENetic Determinants of Restenosis (GENDER) study. Analysis of ~550 000 single nucleotide polymorphisms (SNPs) in GENDER was followed by a replication phase in three independent case-control populations (533 cases and 3067 controls). A potential susceptibility locus for restenosis at chromosome 12, including rs10861032 (P(combined) = 1.11 × 10(-7)) and rs9804922 (P(combined) = 1.45 × 10(-6)), was identified in the GWAS and replication phase. In addition, both SNPs were also associated with coronary events (rs10861032, P(additive) = 0.005; rs9804922, P(additive) = 0.023) in a trial based cohort set of elderly patients with (enhanced risk of) CAD (PROSPER) and all-cause mortality in PROSPER (rs10861032, P(additive) = 0.007; rs9804922, P(additive) = 0.013) and GENDER (rs10861032, P(additive) = 0.005; rs9804922, P(additive) = 0.023). Further analysis suggests that this locus could be involved in regulatory functions.

The scaffolding protein EBP50 promotes vascular smooth muscle cell proliferation and neointima formation by regulating Skp2 and p21(cip1)

OBJECTIVE

The Ezrin-radixin-moesin-binding phosphoprotein 50 (EBP50) is a scaffolding protein known to regulate ion homeostasis in the kidney and intestine. Previous work showed that EBP50 expression increases after balloon injury in rat carotids. This study was designed to determine the role of EBP50 on vascular smooth muscle cells (VSMC) proliferation and the development of neointimal hyperplasia.

METHODS AND RESULTS

Wire injury was performed in wild type (WT) and EBP50 knockout (KO) mice. Two weeks after injury, neointima formation was 80% lower in KO than in WT mice. Proliferation of KO VSMC was significantly lower than WT cells and overexpression of EBP50 increased VSMC proliferation. Akt activity and expression of S-phase kinase protein2 decreased in KO cells resulting in the stabilization of the cyclin-dependent kinase inhibitor, p21(cip1). Consequently, KO cells were arrested in G(0)/G(1) phase. Consistent with these observations, p21(cip1) was detected in injured femoral arteries of KO but not WT mice. No differences in apoptosis between WT and KO were observed.

CONCLUSIONS

EBP50 is critical for neointima formation and induces VSMC proliferation by decreasing S-phase kinase protein2 stability, thereby accelerating the degradation of the cell cycle inhibitor p21(cip1).

Do statins have a role in reduction/prevention of post-PCI restenosis?

The pathophysiology of post-PCI restenosis involves neointimal formation that consists of three phases: thrombosis (within 24 h), recruitment (3-8 days), and proliferation, which starts on day 8 of PCI. Various factors suggested to be predictors/risks for restenosis include C-reactive protein (CRP), inflammatory mediators (cytokines and adhesion molecules), oxygen radicals, advanced glycation end products (AGEs) and their receptors (RAGE), and soluble RAGE (sRAGE). The earlier noted factors produce thrombogenesis, vascular smooth muscle cell proliferation, and extracellular matrix formation. Statins have pleiotropic effects. Besides lowering serum cholesterol, they have various other biological effects including antiinflammatory, antithrombotic, CRP-lowering, antioxidant, antimitotic, and inhibition of smooth muscle cell proliferation. They inhibit matrix metalloproteinase and cyclooxygenase-2, lower AGEs, decrease expression of RAGE and increase levels of serum sRAGE. They also increase the synthesis of nitric oxide (NO) by increasing endothelial NO synthase expression and activity. Preprocedural statin therapy is known to reduce peri- and post-PCI myonecrosis and reduce the need for repeat revascularization. There is evidence that statin-eluting stents inhibit in-stent restenosis in animal models. It is concluded that because of the above attributes of statins, they are suitable candidates for reduction of post-PCI restenosis and post-PCI myonecrosis. The future directions for the use of statins in reduction of post-PCI restenosis and myonecrosis have been discussed.

Genetic causation of neointimal hyperplasia in hemodialysis vascular access dysfunction

The major cause of hemodialysis vascular access failure is venous stenosis resulting from neointimal hyperplasia. Genetic factors have been shown to be associated with cardiovascular disease and peripheral vascular disease (PVD) in the general population. Genetic factors may also play an important role in vascular access stenosis and development of neointimal hyperplasia by affecting pathways that lead to inflammation, endothelial function, oxidative stress, and vascular smooth muscle proliferation. This review will discuss the role of genetics in understanding neointimal hyperplasia development in hemodialysis vascular access dysfunction and other disease processes with similar neointimal hyperplasia development such as coronary artery disease and PVD.

Stent-induced coronary artery stenosis characterized by multimodal nonlinear optical microscopy

We demonstrate for the first time the applicability of multimodal nonlinear optical (NLO) microscopy to the interrogation of stented coronary arteries under different diet and stent deployment conditions. Bare metal stents and Taxus drug-eluting stents (DES) were placed in coronary arteries of Ossabaw pigs of control and atherogenic diet groups. Multimodal NLO imaging was performed to inspect changes in arterial structures and compositions after stenting. Sum frequency generation, one of the multimodalities, was used for the quantitative analysis of collagen content in the peristent and in-stent artery segments of both pig groups. Atherogenic diet increased lipid and collagen in peristent segments. In-stent segments showed decreased collagen expression in neointima compared to media. Deployment of DES in atheromatous arteries inhibited collagen expression in the arterial media.

Combined superoxide dismutase mimetic and peroxynitrite scavenger protects against neointima formation after endarterectomy in association with decreased proliferation and nitro-oxidative stress

OBJECTIVE

Reactive oxygen and nitrogen species (e.g., peroxynitrite) may trigger neointima formation leading to restenosis. In a rat carotid endarterectomy (CEA) model, we investigated the effects of the manganese(III)tetrakis(4-benzoic acid)porphyrin (MnTBAP), a superoxide dismutase (SOD) mimetic and peroxynitrite scavenger on neointima formation.

METHODS

CEA was performed in male Sprague-Dawley rats. Animals received either vehicle (control group; n=15) or 15 mg kg(-1) day(-1) MnTBAP intraperitoneally for 3 weeks (treatment group; n=13). Four groups of carotids were analysed: the left, uninjured carotids (sham) and the right, injured carotids (control CEA) from the control group, the right, injured carotids from the treatment group (CEA+MnTBAP) and an additional group of carotids that were harvested 1h following endarterectomy. The analysis of carotid arteries was performed by histology, immunohistochemistry and real-time polymerase chain reaction (PCR). Plasma malondialdehyde (MDA) levels were measured by lipid hydroperoxidase assay.

RESULTS

Stenosis rate (10.5+/-8.1% vs. 45.4+/-28.3%), the percentage of proliferating cell nuclear antigen-positive cells (13.4+/-7.1% vs. 23.3+/-11.0%) and nitrotyrosine immunoreactivity (5.8+/-1.9 vs. 8.0+/-2.0) were significantly reduced in the vascular wall of the CEA+MnTBAP group compared with control CEA group. Ratio of Terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labelling (TUNEL)-positive nuclei was significantly lower after antioxidant therapy (41.7+/-26.7% vs. 64.9+/-18.5%). Plasma MDA levels increased after endarterectomy (11.7+/-4.8 vs. 4.1+/-2.0 micromol l(-1)) and reduced in the treatment group (3.2+/-2.1 micromol l(-1)). No significant gene regulation after MnTBAP treatment could be noted.

CONCLUSIONS

MnTBAP decreased neointima formation, which was associated with reduced vascular smooth muscle cell proliferation and attenuated local and systemic nitro-oxidative stress.

A link between stent radial forces and vascular wall remodeling: the discovery of an optimal stent radial force for minimal vessel restenosis

Coronary and peripheral artery disease (PAD) continue to be primary causes of morbidity and mortality in western nations; percutaneous transluminal angioplasty (PTA) with stenting has become a popular treatment. Unfortunately, restenosis is a significant problem following intravascular stent placement. This study considers the contribution of stent forces in vascular stenosis and remodeling to develop an equation for identifying the optimal stent force. z-Type stents of three radial forces [low (3.4 N), high (16.4 N), and ultrahigh (19.4 N)] were deployed into the iliac arteries of a juvenile porcine model. Vessel diameters were measured before, after deployment, and again at 30 days. At 30 days animals were killed and the vessels fixed in situ. After implantation, there was a significant increase in total thickness and neointimal hyperplasia with increasing stent force. The model for vessel radius and experimental data was in agreement. The model shows that maximum late-term radius is achieved with a stent deployment stress of 480 kPa, which occurs at the end of the stress-strain curve nonlinear domain and beginning of the high-strain collagen domain. The results and calculations suggest that an optimal stent force exists that is subject to the geometry, structure, and mechanics of the target vessel. To achieve maximum late-term dilatation, stents should not produce stress in the vessel wall greater than the end of the transitional domain of the vessel's stress-strain curve. This finding is extremely important for vascular stent development and will be expanded to preliminary vessel wall injury and atherosclerotic models.

In vitro and in vivo studies of local arterial gene delivery and transfection using lipopolyplexes-embedded stents

Gene-eluting stents can have profound impact in the treatment of coronary restenosis, especially when the encoded protein can re-endothelialize the arterial lumen. In this study, we have examined gene delivery in vitro and in vivo using poly(beta-amino ester) (PbAE) precondensed plasmid DNA-containing cationic liposomes or lipopolyplexes (LPP) immobilized on stainless steel meshes and stents using gelatin coatings. In vitro studies using LPP-immobilized on 50 mm round meshes using type A and B gelatin coatings showed that LPP were efficiently internalized in human aortic smooth muscle cells (SMC) over time, leading to green fluorescent protein (GFP) expression. Type B gelatin coating was found to be more effective in intracellular delivery and transgene expression efficiency and, as such, was used for stent coating. In vivo studies, carried out in iliac artery restenosis model in New Zealand white rabbits, also showed GFP expression in arterial tissues after 24 h of implantation. Based on these encouraging preliminary results, LPP-based formulations can serve as a safe and effective nonviral gene delivery system for effective treatment of coronary restenosis.

Factors that affect mass transport from drug eluting stents into the artery wall

Coronary artery disease can be treated by implanting a stent into the blocked region of an artery, thus enabling blood perfusion to distal vessels. Minimally invasive procedures of this nature often result in damage to the arterial tissue culminating in the re-blocking of the vessel. In an effort to alleviate this phenomenon, known as restenosis, drug eluting stents were developed. They are similar in composition to a bare metal stent but encompass a coating with therapeutic agents designed to reduce the overly aggressive healing response that contributes to restenosis. There are many variables that can influence the effectiveness of these therapeutic drugs being transported from the stent coating to and within the artery wall, many of which have been analysed and documented by researchers. However, the physical deformation of the artery substructure due to stent expansion, and its influence on a drugs ability to diffuse evenly within the artery wall have been lacking in published work to date. The paper highlights previous approaches adopted by researchers and proposes the addition of porous artery wall deformation to increase model accuracy.