Is inflammation a contributor for coronary stent restenosis?

FAK Activation Promotes SMC Dedifferentiation via Increased DNA Methylation in Contractile Genes

Rationale: Vascular smooth muscle cells (SMCs) exhibit remarkable plasticity and can undergo dedifferentiation upon pathological stimuli associated with disease and interventions. Objective: Although epigenetic changes are critical in SMC phenotype switching, a fundamental regulator that governs the epigenetic machineries regulating the fate of SMC phenotype has not been elucidated. Methods and Results: Using SMCs, mouse models, and human atherosclerosis specimens, we found that focal adhesion kinase (FAK) activation elicits SMC dedifferentiation by stabilizing DNA methyltransferase 3A (DNMT3A). FAK in SMCs is activated in the cytoplasm upon serum stimulation in vitro or vessel injury and active FAK prevents DNMT3A from nuclear FAK-mediated degradation. However, pharmacological or genetic FAK catalytic inhibition forced FAK nuclear localization, which reduced DNMT3A protein via enhanced ubiquitination and proteasomal degradation. Reduced DNMT3A protein led to DNA hypomethylation in contractile gene promoters, which increased SMC contractile protein expression. RNA sequencing identified SMC contractile genes as a foremost upregulated group by FAK inhibition from injured femoral artery samples compared to vehicle group. DNMT3A knockdown in injured arteries reduced DNA methylation and enhanced contractile gene expression supports the notion that nuclear FAK-mediated DNMT3A degradation via E3 ligase TRAF6 drives differentiation of SMCs. Furthermore, we observed that SMCs of human atherosclerotic lesions exhibited decreased nuclear FAK, which was associated with increased DNMT3A levels and decreased contractile gene expression. Conclusions: This study reveals that nuclear FAK induced by FAK catalytic inhibition specifically suppresses DNMT3A expression in injured vessels resulting in maintaining SMC differentiation by promoting the contractile gene expression. Thus, FAK inhibitors may provide a new treatment option to block SMC phenotypic switching during vascular remodeling and atherosclerosis.

The relationship between neutrophil-lymphocyte ratio and in-stent restenosis in superficial femoral artery

The present study aimed to investigate the relationship between an increase in the pre- and post-operative neutrophil–lymphocyte ratio (NLR) and superficial femoral artery in-stent restenosis (ISR) rate. We recruited 199 patients that underwent superficial femoral artery stenting for lower extremity arteriosclerosis obliterans at our hospital from March 2015 to July 2018. Patients were divided into two groups according to the occurrence of ISR within 1 year (group 1, ISR and group 2, Non-ISR). The after NLR (NLR_after) and NLR change ratio (NLR_ratio) (P<0.001) were significantly higher in group 1. A NLR_after > 4.3 was associated with an odds ratio of 1.946 (95% CI [1.51–2.50]; P<0.001) for the presence of ISR. A NLR_ratio > 37.5% was associated with an odds ratio of 3.6 (95% CI [2.03–6.36]; P<0.001) for occurrence of ISR. A NLR_after level > 4.3 had 75% sensitivity and 76% specificity for the prediction of ISR, as identified by the ROC curve. A NLR_ratio level > 37.5% predicted ISR with 77% sensitivity and 60% specificity. Multivariate logistic regression analysis demonstrated that NLR_ratio was the strongest independent predictor of ISR (P<0.001). In conclusions, NLR_ratio could be used as a prognostic marker in superficial femoral artery stents.

Surface-Degradable Drug-Eluting Stent with Anticoagulation, Antiproliferation, and Endothelialization Functions

Drug-eluting stents (DES) have been widely applied for saving the life of patients with coronary artery diseases (CADs). However, conventional polymers such as polylactic acid (PLA) and poly (lactic-co-glycolic acid) (PLGA), which are widely applied for drug-eluting stents studies, have serious bulk erosion problems, like high local acidity and poor mechanical properties. Instead, we chose surface erosion polymer poly (1, 3-trimethylene carbonate) (PTMC) as a drug carrier in this study. Here, we fabricated and characterized a novel durable-polymer drug-eluting 316 L stainless steel (SS) stent, in which the inner surface was coated with a Ti–O film using the magnetron sputtering method to promote the growth of endothelial cells (ECs). On the outer layer of the stent, first, a Ti–O film was deposited and, then, on top of it a rapamycin-loaded PTMC coat was deposited using the ultrasonic atomization spray method. This dual coating inhibited the migration and expansion of smooth muscle cells (SMCs). The drug coating also inhibited the adhesion/activation of platelets. In tests on dogs, it was found the novel stent promoted re-endothelialization and reduced restenosis, in contrast to the plain SS stent. Thus, the novel stent may have promise for use in treating patients with CAD.

Design, preparation and performance of a novel drug-eluting stent with multiple layer coatings

Drug-eluting stents (DESs) can effectively control the harmful effects of coronary artery disease, because of their excellent ability to reduce in-stent restenosis. However, delayed re-endothelialization and late stent thrombosis have caused concern over the safety of DESs. In this study, according to time-ordered pathological responses after stent implantation, a hierarchical multiple drug-eluting stent was designed and prepared to overcome the existing DES limitations. A platelet membrane glycoprotein IIIa monoclonal antibody (SZ-21) and a vascular endothelial growth factor (VEGF₁₂₁) were loaded into the inner coating of 316L stainless steel (316L SS) stents to inhibit thrombosis and promote re-endothelialization; rapamycin (RAPA) was loaded into the third layer to inhibit intima hyperplasia; a drug-free poly-l-lactic acid coating was located on the second and fourth layers and used as sustained release layers. The results showed that the three drugs exhibited sequential release kinetics without significant burst release. RAPA released quickly at the early stage, while SZ-21 and VEGF₁₂₁ achieved a slow and prolonged release. In vitro experiments showed that the stents had excellent hemocompatibility and anti-inflammatory properties, and promoted the proliferation and migration of endothelial cells while inhibiting the proliferation and migration of smooth muscle cells. Finally the stents were implanted in the carotid arteries of New Zealand white rabbits. In vivo results showed that compared to 316L SS stents, the multiple drug-eluting stents could accelerate re-endothelialization and inhibit thrombosis, inflammation and in-stent restenosis after 4 weeks (12.79 ± 2.45% vs. 25.27 ± 4.81%) and 12 weeks (15.87 ± 3.62% vs. 58.84 ± 6.87%). These results indicate that the novel drug-eluting stent with multiple layer coatings will have a highly potential clinical application.

Surface modification with dopamine and heparin/poly-L-lysine nanoparticles provides a favorable release behavior for the healing of vascular stent lesions

Surface biofunctional modification of coronary artery stents to prevent thrombosis and restenosis formation, as well as accelerate endothelialization, has become a new hot spot. However, bioactive coatings on implants are not yet sufficiently developed for long-term activity, as they quickly lose efficiency in vivo and finally fail. On the basis of a novel time-ordered concept of biofunctionality for vascular stents, heparin/poly l-lysine nanoparticle (NP) was developed and immobilized on a polydopamine-coated titanium surface, with the aim of regulating and maintaining the intravascular biological response within the normal range after biomaterial implantation. An in vitro dynamic release model was established to mimic the blood flow condition in vivo with three phases: (1) An early phase (1-7 days) with release of predominantly anticoagulant and anti-inflammatory substances and to a minor degree antiproliferative effects against smooth muscle cells (SMCs); (2) this is followed by a phase (7-14 days) of supported endothelial cell (ECs) proliferation and suppressed SMC proliferation with persisting high antithrombogenicity and anti-inflammatory properties of the surface. (3) Finally, a stable stage (14-28 days) with adequate biomolecules on the surface that maintain hemocompatibility and anti inflammation as well as inhibit SMCs proliferation and promote ECs growth. In vivo animal tests further confirmed that the NP-modified surface provides a favorable release behavior to apply a stage-adjusted remedy. We suggested that these observations provide important guidance and potential means for reasonable and suitable platform construction on a stent surface.

Anti-inflammatory effects of arsenic trioxide eluting stents in a porcine coronary model

Previous research from our group has demonstrated arsenic trioxide eluting stents significantly reduced neointimal area and thickness compared with bare metal stents. In the present study, the anti-inflammatory effects of arsenic trioxide in vitro and arsenic trioxide eluting stents in a porcine coronary model have been explored. Sixty-five pigs underwent placement of 139 oversized stents in the coronary arteries with histologic analysis, endothelial function analysis, and immunohistochemical and western blot analyses. Arsenic trioxide eluting stents effectively inhibited local inflammatory reactions, while no significant difference in endothelialization and endothelial function between arsenic trioxide eluting stents and bare metal stents was observed. Arsenic trioxide eluting stents favorably modulate neointimal formation due to less augmentation of early inflammatory reactions, and quick endothelialization of the stent surface, which might contribute to long-term safety and efficacy of drug eluting stents.

Usefulness of the neutrophil-to-lymphocyte ratio to predict bare-metal stent restenosis

Inflammation plays a crucial role in the pathogenesis of in-stent restenosis (ISR). Neutrophil-to-lymphocyte ratio (NLR) provides a simple method for assessment of inflammatory status and prognosis in patients with coronary artery disease. The aim of the present study was to investigate the predictive value of preprocedural NLR on development of ISR in patients undergoing coronary stent implantation. We retrospectively analyzed clinical, hematologic, and angiographic data of 624 patients (mean age 60.5 ± 10.2 years, 71.8% men) who had undergone coronary stent implantation and a further control coronary angiography owing to stable or unstable angina pectoris. Patients were divided into 3 tertiles based on preprocedural NLR. Restenosis occurred in 21 patients (10.1%) in the lowest tertile, in 62 (29.8%) in the middle tertile, and in 107 (51.4%) in the highest NLR tertile (p <0.001). Serum C-reactive protein levels were also significantly higher in patients in tertile 3 than in those in tertiles 1 and 2 (p <0.001). Using multiple logistic regression analysis, smoking, diabetes mellitus, stent length, preprocedural NLR, and C-reactive protein levels emerged as independent predictors of ISR. In receiver operating characteristics curve analysis, NLR >2.73 had 80% sensitivity and 75% specificity in predicting ISR. In conclusion, high preprocedural NLR is a powerful and independent predictor of bare-metal stent restenosis in patients with stable and unstable angina pectoris.

Urinary trypsin inhibitor reduced inflammatory response after stent injury in minipig

This study investigated whether urinary trypsin inhibitor (UTI) inhibits neointimal formation by reducing inflammatory response after stent injury. Twenty minipigs having undergone oversized bare material stent implantation in the left anterior descending artery were randomly subdivided into two groups: a UTI group (n=10) and a control group (n=10). Two systemic markers of inflammation (serum macrophage chemoattractant protein-1 and interleukin-6 levels measured by ELISA) were increased after stent implantation, and two days after stem implantation, their levels were positively correlated with the maximal percentage of area stenosis on day 28 (r(2)=0.889 and 0.743, respectively). This effect was abolished by UTI administration. Twenty-eight days after implantation, morphometric analysis of the stented arteries revealed significantly reduced luminal stenosis (38±6% vs. 64±12%, P<0.05), a neointimal area (3.22±0.57 mm(2) vs. 5.21±1.04 mm(2), P<0.05), neointimal thickness (0.31±0.13 mm vs. 0.46±0.16 mm, P<0.05), and an inflammatory score of 1.02±0.05 vs. 1.30±0.08 in UTI-treated animals as compared with controls. Twenty-eight days after stenting, arterial nuclear factor-κB expression was 36.93±7.16% in all of the cells in controls and 23.32±4.54% in UTI-treated minipigs. UTI could reduce neointimal formation after stenting by inhibiting the local and the systemic inflammatory response. Percutaneous coronary intervention could benefit from precocious anti-inflammatory treatment.

High soluble Fas and soluble Fas Ligand serum levels before stent implantation are protective against restenosis

Percutaneous coronary intervention (PCI) represents the most important treatment of coronary artery stenosis today. But instent restenosis (ISR) is a limitation for the outcome. Fas and Fas Ligand have been implicated in apoptosis and vessel wall inflammation. Their role in ISR is not known so far. In this prospective study we studied 137 patients with stable coronary artery disease who underwent elective PCI. Blood samples were taken directly before and 24 hours after PCI. Soluble (s)Fas and sFas Ligand serum levels were measured by ELISA. Restenosis was evaluated six to eight months later either by coronary angiography or by exercise testing. During the follow-up period, 18 patients (13%) developed ISR. At baseline, patients with ISR had significantly lower median sFas, as well as sFas Ligand levels compared to patients without ISR (sFAS: ISR 492 pg/ml, no ISR 967 pg/ml, p=0.014; sFAS Ligand: ISR: 26 pg/ml, no ISR: 42 pg/ml, p=0.001). After PCI median sFas levels significantly decreased in patients with ISR compared to patients without ISR [ISR: -152 pg/ml (IQR -36 to -227), no ISR: -38 pg/ml (IQR -173 to +150 pg/ml), p=0.03]. sFas Ligand levels after PCI significantly increased in ISR patients compared to patients without ISR [ISR: 14 pg/ml (IQR -3 to +26 pg/ml), no ISR -6 pg/ml (IQR -22 to +21 pg/ml), p=0.014]. In conclusion, sFas and sFas Ligand seem to be associated with the development of ISR. Determination of serum levels before and after PCI might help identifying patients at higher risk of ISR.

Comparison of changes in early inflammatory markers between sirolimus- and paclitaxel-eluting stent implantation

BACKGROUND

Systemic inflammation after coronary intervention identifies patients at increased risk of subsequent cardiac events. Cardiac events, especially in-stent restenosis, are less frequent after use of sirolimus-eluting stent (SES) compared with paclitaxel-eluting stent (PES). However, the underlying mechanism for this disparity is not well investigated. We hypothesize that an attenuated inflammatory response after SES implantation may be a contributor.

PURPOSE

In the present study, we sought to determine the early inflammatory response after SES implantation in patients with single-vessel disease compared with PES implantation, and evaluate the relationship between inflammatory response and late clinical outcomes in a randomized design.

METHODS

Thirty-two patients with stable angina were randomly enrolled into the two groups, SES or PSE group (n = 16 respectively). Peripheral blood samples were taken before PCI, 24 and 72 h after stenting. The plasma concentrations of C-reactive protein (CRP) and interleukin-6 (IL-6) were determined by enzyme-linked immunosorbent assay (ELISA). The clinical and angiographic follow-up was performed at 8 months after stenting.

RESULTS

The data showed that there was no significant difference in clinical and angiographic baseline characteristics between the two groups. The plasma CRP and IL-6 levels at 24 h after stenting were significant higher in both groups compared with baseline (p < 0.01 respectively). Likewise, the CRP levels at 72 h after stenting were also significant higher compared with baseline in both groups (p < 0.01 respectively). However, the plasma levels of IL-6 at 24 h and CRP at 72 h after stenting were higher in PES group compared with SES group (p < 0.05). At 8 months follow-up, the rates of major adverse cardiac events, target lesion revascularization, in-stent and in-segment restenosis were similar in both groups. However, the late loss in both in-stent and in-segment was significantly higher in the PES group than in SES group (p < 0.001 respectively).

CONCLUSIONS

Our findings suggest that a drug-eluting stent implantation could trigger a systemic inflammatory response as previously demonstrated. However, SES implantation results in a lower inflammatory response compared with PES implantation, which seems to be associated with greater late of in-stent and in-segment loss at 8-month follow-up with PES.

Randomized comparison of early inflammatory response after sirolimus-eluting stent vs bare metal stent implantation in native coronary lesions

BACKGROUND

The clinical significance of early inflammatory response after coronary stent implantation has been controversial. Sirolimus-eluting stent (SES) has been shown to be better outcomes compared with bare metal stent (BMS). We prospectively investigated the early inflammatory response after SES or BMS implantation in patients with single-vessel lesion, and evaluated the relationship between inflammation and late clinical outcomes in a randomized design.

METHODS

Forty-eight patients with single-vessel disease were randomized into SES or BMS implantation group (n=24 respectively). Blood samples were taken before stenting, 1 h, 24 h and 8 months afterward. The plasma concentrations of C-reactive protein (CRP) and interleukin-6 (IL-6) were determined by ELISA. The clinical and angiographic follow-up were performed at 8 months after stenting.

RESULTS

There was no difference in baseline characteristics, plasma CRP and IL-6 concentrations between the 2 groups. However, plasma IL-6 concentrations at 1 h after stenting were higher in both groups than in baseline (p<0.01). In addition, the plasma CRP and IL-6 concentrations at 24 h after stenting were significantly higher in both groups compared with baseline (p<0.01 respectively). Likewise, plasma CRP and IL-6 concentrations were significantly higher in BMS group compared with SES group at 24 h after stenting (p<0.05 respectively). At the follow-up (mean 8 months after stenting), the rate of in-stent restenosis (ISR) and target lesion revascularization (TLR) were higher in BMS group than in SES group (p<0.05 respectively) although the plasma CRP and IL-6 concentrations are similar between the groups.

CONCLUSIONS

Single coronary stenting could trigger an early inflammatory response. However, patients undergoing SES implantation has less augmentation of early inflammatory markers after stenting compared to patients treated with BMS, which was positively related the incidence of ISR and TLR at follow-up. This may reflect the potential impact of SES implantation on the early inflammatory response and late clinical outcomes.

Cytokines and coronary artery disease: the state of the art

Initiation and progression of coronary atherosclerosis has been associated with inflammation and cytokines balance. The objective of this study is to understand the role of cytokines in the pathophysiology and management of coronary artery disease. Coronary artery disease has been revisited with revision of the pertinent published articles in the Medline, Scopus, and EBSCO Host research from 1987 to 2007. The 2 groups of cytokines (proinflammatory and anti-inflammatory) have been detected in human atherosclerotic plaques. The balance between the 2 groups may reflect the intensity of occult plaque inflammation and the vulnerability to rupture. Multiple studies have determined that a diverse set of proinflammatory biomarkers can furnish prognostic information beyond the traditional risk factors. Inflammatory responses after coronary revascularization are known to play key role in vascular lesion formation early in atherosclerosis and restenosis. Clinical utilization of cytokines remains promising yet incompletely explored and need more studies.

Coronary restenotic reduction of drug-eluting stenting may be due to its anti-inflammatory effects

The development of coronary stent has revolutionized the field of interventional cardiology by reducing the incidence of restenosis after balloon angioplasty. However, the stent has still associated with a serious complication, namely, in-stent restenosis. Although, restenosis following coronary stenting has long been attributed to neointimal proliferation, thrombosis, and negative remodeling, the inflammation may be a trigger for those vascular reactions following coronary stenting. Both experimental and clinical studies have demonstrated a marked activation of local and systemic inflammatory response following stent implantation, suggesting that inflammation may play an important role in determining in-stent restenosis via neointimal proliferation. The key role of inflammation in vascular healing and in-stent retsenosis has also been increasingly well understood. Recently, drug-eluting stents (DESs) have been shown to decrease in-stent restenosis in a large number of clinical studies. In addition to their anti-proliferative activity, DESs have been considered to possess an anti-inflammatory property, especially for sirolimus-eluting stent compared with bare metal stent. Moreover, the benefit of the anti-inflammatory therapy during the peri-procedural period and long-term follow-up by means of drug administration is also dependent on the inflammatory status during percutaneous coronary intervention. Measurement of cytokine and acute phase proteins, such as C-reactive protein, therefore, may be important to identify high-risk subjects and develop specific treatment tailored to the individual patients with stent restenosis. Thus, therapeutic approach should be further directed toward increasing local resistance to proliferative inflammatory stimuli by means of anti-proliferative, locally delivered drugs and reducing the magnitude and persistence of systemic inflammation.