Eosinophilic infiltration in restenotic tissue following coronary stent implantation

In-stent restenosis after percutaneous coronary intervention: emerging knowledge on biological pathways

Percutaneous coronary intervention (PCI) has evolved significantly over the past four decades. Since its inception, in-stent restenosis (ISR)-the progressive reduction in vessel lumen diameter after PCI-has emerged as the main complication of the procedure. Although the incidence of ISR has reduced from 30% at 6 months with bare-metal stents to 7% at 4 years with drug-eluting stents (DESs), its occurrence is relevant in absolute terms because of the dimensions of the population treated with PCI. The aim of this review is to summarize the emerging understanding of the biological pathways that underlie ISR. In-stent restenosis is associated with several factors, including patient-related, genetic, anatomic, stent, lesion, and procedural characteristics. Regardless of associated factors, there are common pathophysiological pathways involving molecular phenomena triggered by the mechanical trauma caused by PCI. Such biological pathways are responses to the denudation of the intima during balloon angioplasty and involve inflammation, hypersensitivity reactions, and stem cell mobilization particularly of endothelial progenitor cells (EPCs). The results of these processes are either vessel wall healing or neointimal hyperplasia and/or neo-atherosclerosis. Unravelling the key molecular and signal pathways involved in ISR is crucial to identify appropriate therapeutic strategies aimed at abolishing the 'Achille's heel' of PCI. In this regard, we discuss novel approaches to prevent DES restenosis. Indeed, available evidence suggests that EPC-capturing stents promote rapid stent re-endothelization, which, in turn, has the potential to decrease the risk of stent thrombosis and allow the use of a shorter-duration dual antiplatelet therapy.

Hypersensitivity and in-stent restenosis in coronary stent materials

Coronary heart disease (CHD) is a type of cardiovascular disease with the highest mortality rate worldwide. Percutaneous transluminal coronary intervention (PCI) is the most effective method for treating CHD. However, in-stent restenosis (ISR), a long-term complication after PCI, affects the prognosis of patients with CHD. Previous studies have suggested that hypersensitivity reactions induced by metallic components may be one of the reasons of this complication. With the emergence of first- and second-generation drug-eluting stents (DES), the efficacy and prognosis of patients with CHD have greatly improved, and the incidence of ISR has gradually decreased to less than 10%. Nevertheless, DES components have been reported to induce hypersensitivity reactions, either individually or synergistically, and cause local inflammation and neointima formation, leading to long-term adverse cardiovascular events. In this article, we described the relationship between ISR and hypersensitivity from different perspectives, including its possible pathogenesis, and discussed their potential influencing factors and clinical significance.

The Early Predictive Value of Circulating Monocytes and Eosinophils in Coronary DES Restenosis

Background

Monocytes and eosinophils are involved in intracoronary inflammatory responses, aggravating coronary artery plaque instability and in-stent restenosis (ISR).

Aims

To investigate an early prediction of ISR in patients undergoing stenting by circulating monocytes and eosinophils.

Methods

The single-center data of patients undergoing successful drug-eluting stents (DES) implantation from January 1, 2017 to April 30, 2020 were retrospectively analyzed. Of the 4,392 patients assessed, 140 patients with restenosis and 141 patients without restenosis were enrolled. A scheduled postoperative follow-up was proceeded in four sessions: 0-3 months, 3-6 months, 6-12 months, and >12 months. The hematological and biochemical measurement was collected. The angiographic review was completed within two postoperative years.

Results

Significant associations of monocyte count and percentage with ISR were evident [odds ratio (OR): 1.44, 95% CI: 1.23-1.68, P < 0.001; OR: 1.47, 95%CI: 1.24-1.74, P < 0.001, respectively], which began at 3 months postoperatively and persisted throughout the follow-up period. Eosinophil count and percentage were associated with ISR (OR: 1.22, 95%CI: 1.09-1.36, P = 0.001; OR: 1.23, 95%CI: 1.07-1.40, P = 0.003, respectively), with ISR most significantly associated with the baseline eosinophils. The receiver operating characteristic (ROC) curve analysis showed that the cutoff points of monocyte count and percentage in the ISR prediction were 0.46× 10⁹/L and 7.4%, respectively, and those of eosinophil count and percentage were 0.20 × 10⁹/L and 2.5%, respectively.

Conclusion

This study, with a long-term follow-up, first provides evidence that the elevated monocytes at three postoperative months and baseline eosinophils may be strong early predictors of ISR after drug-eluting stent implantation. Persistent elevation of monocytes may also be a signal of ISR after percutaneous coronary intervention (PCI).

Tissues attached to retrieved leadless pacemakers: Histopathological evaluation of tissue composition in relation to implantation time and complications

BACKGROUND

Leadless pacemakers (LPs) have proven safe and effective, but device revisions remain necessary. Either replacing the LP or implanting a new adjacent LP is feasible. Replacement seems more appealing, but encapsulation and tissue adhesions may hamper the safety and efficacy of LP retrieval.

OBJECTIVE

We determined the incidence and cellular characteristics of tissue adherent to retrieved LPs and the potential implications for end-of-life strategy.

METHODS

All 15 consecutive successful Nanostim LP retrievals in a tertiary center were included. We assessed the histopathology of adherent tissue and obtained clinical characteristics.

RESULTS

Adherent tissue was present in 14 of 15 retrievals (93%; median implantation duration 36 months; range 0-96 months). The tissue consisted of fibrosis (n = 2), fibrosis and thrombus (n = 9), or thrombus only (n = 3). In short-term retrievals (<1 year), mostly fresh thrombi without fibrosis were seen. In later retrievals, the tissue consisted of fibrosis often with organizing or lytic thrombi. Fibrosis showed different stages of organization, notably early fibrocellular and later fibrosclerotic tissue. Inflammatory cells were seen (n = 4) without signs of infection. Tricuspid valve material was retrieved in 1 patient after 36 months, resulting in increased tricuspid regurgitation.

CONCLUSION

Our results suggest that fibrosis and thrombus adherent to LPs are common and encapsulate the LP as seen in transvenous pacemakers. LPs may adhere to the tricuspid valve or subvalvular apparatus affecting retrieval safety. The end-of-life strategy should be optimized by incorporating risk stratification for excessive fibrotic encapsulation and adhesions.

Innate Immune Cells in Pressure Overload-Induced Cardiac Hypertrophy and Remodeling

Pressure overload and heart failure are among the leading causes of cardiovascular morbidity and mortality. Accumulating evidence suggests that inflammatory cell activation and release of inflammatory mediators are of vital importance during the pathogenesis of these cardiac diseases. Yet, the roles of innate immune cells and subsequent inflammatory events in these processes remain poorly understood. Here, we outline the possible underlying mechanisms of innate immune cell participation, including mast cells, macrophages, monocytes, neutrophils, dendritic cells, eosinophils, and natural killer T cells in these pathological processes. Although these cells accumulate in the atrium or ventricles at different time points after pressure overload, their cardioprotective or cardiodestructive activities differ from each other. Among them, mast cells, neutrophils, and dendritic cells exert detrimental function in experimental models, whereas eosinophils and natural killer T cells display cardioprotective activities. Depending on their subsets, macrophages and monocytes may exacerbate cardiodysfunction or negatively regulate cardiac hypertrophy and remodeling. Pressure overload stimulates the secretion of cytokines, chemokines, and growth factors from innate immune cells and even resident cardiomyocytes that together assist innate immune cell infiltration into injured heart. These infiltrates are involved in pro-hypertrophic events and cardiac fibroblast activation. Immune regulation of cardiac innate immune cells becomes a promising therapeutic approach in experimental cardiac disease treatment, highlighting the significance of their clinical evaluation in humans.

Eosinophils improve cardiac function after myocardial infarction

Clinical studies reveal changes in blood eosinophil counts and eosinophil cationic proteins that may serve as risk factors for human coronary heart diseases. Here we report an increase of blood or heart eosinophil counts in humans and mice after myocardial infarction (MI), mostly in the infarct region. Genetic or inducible depletion of eosinophils exacerbates cardiac dysfunction, cell death, and fibrosis post-MI, with concurrent acute increase of heart and chronic increase of splenic neutrophils and monocytes. Mechanistic studies reveal roles of eosinophil IL4 and cationic protein mEar1 in blocking H₂O₂- and hypoxia-induced mouse and human cardiomyocyte death, TGF-β-induced cardiac fibroblast Smad2/3 activation, and TNF-α-induced neutrophil adhesion on the heart endothelial cell monolayer. In vitro-cultured eosinophils from WT mice or recombinant mEar1 protein, but not eosinophils from IL4-deficient mice, effectively correct exacerbated cardiac dysfunctions in eosinophil-deficient ∆dblGATA mice. This study establishes a cardioprotective role of eosinophils in post-MI hearts.

Blood eosinophil (EOS) counts may serve as risk factors for human coronary heart diseases. Here the authors show that increased circulating and myocardial EOS after myocardial infarction play a cardioprotective role by reducing cardiomyocyte death, cardiac fibroblast activation and fibrosis, and endothelium activation-mediated inflammatory cell accumulation.

Anti-Adhesive, Platelet Gathering Effects of c-RGD Modified Poly(p-dioxanone-co-l-Phe) Electrospun Membrane and Its Comprehensive Application in Intestinal Anastomosis

Intestinal resection and anastomosis are performed in over a million people with various bowel diseases annually. Excessive fibrosis and anastomotic site leakage are the main complications of anastomosis surgery, despite great improvements in operative technique and equipment in recent years. In this study, cRGD modified poly(p-dioxanone-co-l-Phe) (PDPA) membranes are designed and applied in intestinal anastomosis to simultaneously solve the two aforementioned complications. cRGD is modified onto PDPA membranes through both physical absorption and π-π accumulation between d-Phe of cRGD and l-Phe of PDPA. Although cRGD modification enhanced the biocompatibility of PDPA membranes, cRGD modified PDPA membrane suppresses fibroblast proliferation both in vitro and in vivo as a result of degradation and subsequent release of fibroblast suppressive l-Phe from PDPA. Meanwhile, platelets are entrapped by cRGD modified PDPA membranes through the specific binding of cRGD and platelet GP_IIbIIIa . cRGD modified PDPA membranes are applied in rat intestinal anastomosis, and both adhesion and stenosis are successfully prevented at anastomotic sites. At the same time, bursting pressure, which represents healing intensity at anastomotic sites, is promoted. The gathering and activation of platelets on PDPA membranes induce secretion of autologous PDGF and VEGF to facilitate angiogenesis and subsequent healing of anastomotic sites.

Role of Allergic Inflammatory Cells in Coronary Artery Disease

Inflammation is an important player both for the initiation and progression of coronary artery disease and for coronary plaque instability. Moreover, inflammation contributes to stent thrombosis and in-stent restenosis after percutaneous coronary intervention. In the past several decades, most studies evaluated the involvement of cellular effectors of classic inflammatory responses, such as monocytes/macrophages, neutrophils, and T cells. Yet, besides classic inflammation, mounting evidence derived from both experimental and clinical studies suggests an important, often unrecognized, role for effector cells of allergic inflammation in both the pathogenesis of coronary artery disease and adverse events following stent implantation. In this review, we discuss the role of effector cells of allergic inflammation in the setting of coronary artery disease progression and instability, and in the occurrence of adverse events following stent implantation, as well. Moreover, we discuss possible therapeutic approaches targeting different specific pathways of allergic inflammatory activation.

The value of peripheral blood eosinophil count in predicting in-stent restenosis in patients with stable angina pectoris undergoing drug eluting stenting

INTRODUCTION

In-stent restenosis (ISR) remains a major limitation of percutaneous coronary intervention (PCI). A role for peripheral blood cells as major regulators of immune and inflammatory systems has been proposed. We aim to evaluate the relationship between eosinophil count and development of restenosis after drug-eluting stent (DES) implantation.

METHODS

In this prospective study, all consecutive patients undergoing elective DES implantation for chronic stable angina (CSA) in a university-affiliated heart center within a 6-month period were enrolled and followed for another 6 months. Complete blood count with differentiation was performed 6 weeks after the index procedure. During the follow-up period, the cohort of patients who developed ISR was compared to the cohort of patients without ISR, descriptively and the total number of eosinophilic white cells was used to predict the occurrence of ISR.

RESULTS

153 men and 48 women with CSA underwent PCI with DES implantation, from which, 26 patients needed repeat coronary angiography for recurrent symptoms. There was an established ISR in 17 (8.5%) patients. The total number of eosinophils in their peripheral blood was 267 ± 132 cells/μL in patients with ISR, significantly higher than the number of eosinophils in those without ISR 174 ± 133 cells/μL (P-value < 0.010). Eosinophil count remained an independent predictor of ISR in multivariate analysis as the eosinophil count value over 242 cells/μL had sensitivity of 66.7% and specificity of 84.5% for the presence of ISR.

CONCLUSION

The total number of eosinophils, counted 6 weeks after DES implantation, prevails as the sole predictor of ISR occurrence in our study. This suggests an association between immune sensitivity reaction to DES material and development of ISR in patients after PCI.

Allergic Inflammation Is Associated With Coronary Instability and a Worse Clinical Outcome After Acute Myocardial Infarction

BACKGROUND

The role of allergic inflammation in acute coronary syndromes (ACS) has not been clearly defined to date. Aim of this study was to assess eosinophil and basophil activation in ACS and the prognostic role of eosinophil cationic protein in ST-segment-elevation myocardial infarction.

METHODS AND RESULTS

In a cross-sectional study, we prospectively enrolled 51 patients undergoing percutaneous coronary intervention (60.8% patients with ACS and 39.2% with stable angina). Flow cytometry analysis assessed CD66b, CD69, and CD203c median fluorescence intensity expression. In a follow-up study, 181 patients presenting with ST-segment-elevation myocardial infarction, undergoing primary percutaneous coronary intervention, were prospectively enrolled with a follow-up of 24 months. Eosinophil activation (CD66b) was similar in patients with ACS and stable angina (6.61 [4.91-7.72] versus 6.62 [5.27-8.73], P=0.63), whereas eosinophil degranulation (CD69) and basophil activation (CD203c) were higher in ACS patients compared with stable angina patients (1.38 [1.16-1.52] versus 1.17 [1-1.31], P=0.01); 0.97 [0.89-1.11] versus 0.92 [0.87-0.95], P=0.03, respectively). Eosinophil cationic protein serum levels were significantly higher in ST-segment-elevation myocardial infarction patients with major adverse cardiac events as compared with those without (21.1 [10.37-25.65] versus 7.83 [3.37-12.8] μg/L, P=0.01) and in patients with thrombus score >3 compared with those with thrombus score ≤3 (15.0 [9.8-24.7] versus 5.2 [3.5-22.9] μg/L, P=0.006). Eosinophil cationic protein serum levels predicted major adverse cardiac events during follow-up (odds ratio =1.041, 95% confidence interval 1.012-1.071, P=0.005). C-reactive protein serum levels showed a borderline statistical significance (odds ratio =0.904, 95% confidence interval 0.806-1.014, P=0.085).

CONCLUSIONS

These findings are the first demonstration of in vivo eosinophil degranulation and basophil activation during ACS and of the prognostic role of eosinophil cationic protein in ST-segment-elevation myocardial infarction.

Vascular injury and repair: a potential target for cell therapies

ABSTRACT 

Whether due to atherosclerotic disease or mechanical intervention, vascular injury is a frequently encountered pathology in cardiovascular medicine. The past decade has seen growing interest in the role of circulating endothelial progenitor cells in vessel recovery postinjury. Despite this, the definition, origin and potential role of endothelial progenitor cells in vascular regeneration remains highly controversial. While animal work has shown early promise, evidence of a therapeutic role for endothelial progenitor cells in humans remains elusive. To date, clinical trials involving direct cell administration, growth factor therapy and endothelial cell capture stents have largely been disappointing, although this may in part reflect limitations in study design. This article will outline the pathophysiological mechanisms of vascular injury with an emphasis on endothelial progenitor cell biology and the potential therapeutic role of this exciting new field.

An increase of interleukin-33 serum levels after coronary stent implantation is associated with coronary in-stent restenosis

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An association between IL-33 and restenosis in coronary artery disease exists.

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IL-33 increase after stent implantation is associated with a higher rate of restenosis.

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IL-33 estimation before and after PCI could determine patients at risk.

The study aim was to determine the predictive value of interleukin (IL)-33, a recently described member of the IL-1 family of cytokines, for the development of in-stent restenosis (ISR). IL-33 serum levels were measured in 387 consecutive patients undergoing percutaneous coronary intervention (PCI) of whom 193 had stable angina, 93 non-ST elevation myocardial infarction (NSTEMI), and 101 ST-elevation MI (STEMI), respectively. Blood was taken directly before and 24 h after stent implantation. The presence of ISR was initially evaluated by clinical means after six to eight months. When presence of myocardial ischemia was suspected, coronary angiography was performed to confirm the suspected diagnosis of ISR. Clinical ISR was present in total in 34 patients (8.8%). IL-33 was detectable in 185 patients and was below detection limit in 202 patients. In patients with decreased IL-33 (n = 95), unchanged or non-detectable levels (n = 210) or increased levels of IL-33 after PCI (n = 82), ISR-rate was 2.1%, 9.5% and 14.6%, respectively (p < 0.05). Accordingly, patients with ISR showed a significant increase of IL-33 upon PCI (p < 0.05). This association was independent from clinical presentation and risk factors as well as numbers and type of stents. In patients with both stable and unstable coronary artery disease, an increase of IL-33 serum levels after stent implantation is associated with a higher rate of in-stent restenosis.

Association between inflammatory biomarkers and in-stent restenosis tissue features: an Optical Coherence Tomography Study

AIMS

Inflammatory reaction after stent implantation is associated with in-stent restenosis (ISR). We assessed the association of optical coherence tomography (OCT) features of neointima with systemic levels of high-sensitivity C-reactive protein (hs-CRP) and eosinophil cationic protein (ECP) measured at the time of ISR detection.

METHODS AND RESULTS

Patients presenting with symptomatic angiographically documented ISR (diameter stenosis ≥ 50% by visual estimation) were included. Quantitative OCT analysis included the measurement of minimal lumen diameter, minimal luminal area, stent and neointimal area, stent and restenosis length, restenotic tissue burden, and symmetry ratio. Qualitative OCT analysis included the assessment of ISR plaque type, neointimal tissue structure, lumen shape, presence of microvessels and calcific nodules. At the time of ISR detection hs-CRP and ECP levels were measured, and statistical analysis was performed using as cut-off 3 mg/L and 4.5 µg/L, respectively. Our population included 40 patients, 24 bare metal stents and 16 drug-eluting stents. Patients with high hs-CRP levels had a higher restenostic tissue symmetry ratio (0.56 ± 0.17 vs. 0.42 ± 0.13, P = 0.01) when compared with patients with low hs-CRP levels. Patients with high ECP levels had a higher neointimal burden (70 ± 14 vs. 64 ± 11, P = 0.05) in comparison with patients with low ECP levels.

CONCLUSIONS

Inflammatory biomarkers assessed at the time of ISR detection are associated with different aspects of neointimal tissue. While hs-CRP seems to have a role in neointimal tissue shape, ECP is related to a neointimal burden.

Evolving management of patients treated by drug-eluting stent: prevention of late events

SUMMARY

Drug eluting stents (DES) were introduced in clinical practice to overcome the problem of in-stent restenosis (ISR) that limited the overall efficacy of percutaneous coronary revascularization with bare metal stent (BMS). Long-term outcome data confirm a sustained benefit of DES as compared with BMS. However, this benefit is mainly evident in the first year of follow-up. Indeed, DES-related events may extend over this time, due to late events (late ISR and/or very late stent thrombosis). Prevention of late failure of DES may become a specific therapeutic target.

Quaking, an RNA-binding protein, is a critical regulator of vascular smooth muscle cell phenotype

RATIONALE

RNA-binding proteins are critical post-transcriptional regulators of RNA and can influence pre-mRNA splicing, RNA localization, and stability. The RNA-binding protein Quaking (QKI) is essential for embryonic blood vessel development. However, the role of QKI in the adult vasculature, and in particular in vascular smooth muscle cells (VSMCs), is currently unknown.

OBJECTIVE

We sought to determine the role of QKI in regulating adult VSMC function and plasticity.

METHODS AND RESULTS

We identified that QKI is highly expressed by neointimal VSMCs of human coronary restenotic lesions, but not in healthy vessels. In a mouse model of vascular injury, we observed reduced neointima hyperplasia in Quaking viable mice, which have decreased QKI expression. Concordantly, abrogation of QKI attenuated fibroproliferative properties of VSMCs, while potently inducing contractile apparatus protein expression, rendering noncontractile VSMCs with the capacity to contract. We identified that QKI localizes to the spliceosome, where it interacts with the myocardin pre-mRNA and regulates the splicing of alternative exon 2a. This post-transcriptional event impacts the Myocd_v3/Myocd_v1 mRNA balance and can be modulated by mutating the quaking response element in exon 2a of myocardin. Furthermore, we identified that arterial damage triggers myocardin alternative splicing and is tightly coupled with changes in the expression levels of distinct QKI isoforms.

CONCLUSIONS

We propose that QKI is a central regulator of VSMC phenotypic plasticity and that intervention in QKI activity can ameliorate pathogenic, fibroproliferative responses to vascular injury.

Clinical and socio-demographic predictors of postoperative vital exhaustion in patients after cardiac surgery

BACKGROUND

Vital exhaustion, a psychological state characterized by extreme fatigue, is an independent predictor of future cardiac events. However, the attributes of vital exhaustion following coronary artery bypass (CABG) surgery are poorly understood.

OBJECTIVE

The study objective was to assess correlates of vital exhaustion following CABG surgery.

METHODS

In a descriptive, exploratory study, 42 patients who had CABG surgery were evaluated for exhaustion 4-8 weeks post-hospital discharge. Demographic and clinical data were obtained from self-report and medical chart review.

RESULTS

Of the total sample (mean age 67.9 ± 12.5, 90% male, 70% Caucasian, 3.12 ± 1.3 grafts), approximately 41% reported exhaustion. When compared to their exhausted post-CABG counterpart, non-exhausted post-CABG patients had a significantly higher frequency of preoperative insulin use. Exhausted patients were significantly more likely to have higher left ventricular ejection fraction ([LVEF], OR: 1.07, p = 0.04), and elevated hemoglobin (OR: 2.98, p = 0.03) and eosinophils (OR: 1.02, p = 0.02) than those who were not exhausted.

CONCLUSION

Clinicians should evaluate all patients for exhaustion post-CABG surgery; patients with elevated LVEF, hemoglobin, and eosinophil levels warrant increased scrutiny.

Expression of inflammatory and apoptosis factors following coronary stent implantation in coronary heart disease patients

We investigated the changes in characteristics of neutrophil CD11b, monocyte CD11b, platelet CD62P, endothelin (ET), and neutrophil CD178 in patients with coronary heart disease (CHD) before and after primary coronary stenting. A total of 41 patients with CHD who underwent coronary stenting and 40 control subjects were enrolled in the study. In CHD patients, peripheral blood samples were taken 24 h before and 30 min, 24 h, and 72 h after successful coronary stenting. All markers were significantly elevated in patients with CHD compared with controls (P<0.05). Time-course studies revealed that the expressions of neutrophil CD11b, monocyte CD11b, platelet CD62P, and ET were lower at 30 min post-operation (PO) compared with that at 24 h before operation (BO) (P<0.05). All levels significantly increased from 30 min PO to 24 h PO (P<0.05) and decreased thereafter until 72 h PO (P>0.05). Time course changes in neutrophil CD11b levels after coronary stenting were significantly higher in patients with unstable angina pectoris than in patients with stable angina pectoris (P<0.05). CD11b levels were related to CD62P in patients with CHD (P<0.05). Neutrophil CD11b and monocyte CD11b levels were significantly increased in patients with CHD who underwent coronary stenting compared with controls (P<0.05). Results show that CD11b levels increased, meanwhile, the levels of CD62P and ET increased in CHD patients after coronary stenting. In addition, neutrophil CD178 levels of apoptosis factor in patients, which is important for regression of inflammation, remained high for a period of time after coronary stenting.

The evolving role of inflammatory biomarkers in risk assessment after stent implantation

The main adverse reactions to coronary stents are in-stent restenosis (ISR) and stent thrombosis. Along with procedural factors, individual susceptibility to these events plays an important role. In particular, inflammatory status, as assessed by C-reactive protein levels, predicts the risk of ISR after bare-metal stent implantation, although it does not predict the risk of stent thrombosis. Conversely, C-reactive protein levels fail to predict the risk of ISR after drug-eluting stent (DES) implantation, although they appear to predict the risk of stent thrombosis. Of note, DES have abated ISR rates occurring in the classical 1-year window, but new concern is emerging regarding late restenosis and thrombosis. The pathogenesis of these late events seems to be related to delayed healing and allergic reactions to polymers, a process in which eosinophils seem to play an important role by enhancing restenosis and thrombosis. The identification of high-risk individuals based on biomarker assessment may be important for the management of patients receiving stent implantation. In this report, we review the evolving role of inflammatory biomarkers in predicting the risk of ISR and stent thrombosis.

Eosinophil cationic protein and clinical outcome after bare metal stent implantation

OBJECTIVE

we assessed the association between baseline eosinophil cationic protein (ECP) levels, a sensitive marker of eosinophil activation, and clinical outcome in patients undergoing bare metal stent (BMS) implantation.

METHODS

basal ECP levels were measured in 110 patients (69±11 years, 88 men) undergoing BMS implantation. Major adverse cardiac events (MACEs), defined as cardiac death, non-fatal myocardial infarction, or clinically-driven target lesion revascularization, were registered at 24-month follow-up.

RESULTS

eighteen (16.4%) patients had MACEs and showed higher ECP levels compared with those without MACEs [20.1 (9.8-47.3) vs. 9.5 (5.0-27.2) g/L, p=0.02]. At follow-up, ECP level>11 g/L was the only significant predictor of MACEs (HR 3.5, 95% CI 1.1-10.4, p=0.03).

CONCLUSION

basal ECP levels are associated with MACEs after BMS implantation, suggesting that an allergic-mediated inflammation against the metal could explain some adverse reactions occurring after coronary stenting.

Myeloid cells in atherosclerosis: initiators and decision shapers

Chronic inflammation is the underlying pathophysiological mechanism of atherosclerosis. Prominent suspects being involved in atherosclerosis are lymphocytes, platelets, and endothelial cells. However, recent advances suggest a potent role for myeloid leukocytes, specifically monocyte subsets, polymorphonuclear leukocytes, and mast cells. These three cell types are not just rapidly recruited or already reside in the vascular wall but also initiate and perpetuate core mechanisms in plaque formation and destabilization. Dendritic cell subsets as well as endothelial and smooth muscle progenitor cells may further emerge as important regulators of atheroprogression. To stimulate further investigations about the contribution of these myeloid cells, we highlight the current mechanistic understanding by which these cells tune atherosclerosis.

An essential role for gp130 in neointima formation following arterial injury

Interleukin (IL)-6 induced vascular smooth muscle cell (VSMC) motility in a dose-dependent manner. In addition, IL-6 stimulated tyrosine phosphorylation of gp130, resulting in the recruitment and activation of STAT-3. IL-6-induced VSMC motility was found to be dependent on activation of gp130/STAT-3 signaling. IL-6 also induced cyclin D1 expression in a time- and gp130/STAT-3-dependent manner in VSMCs. Suppression of cyclin D1 levels via the use of its small interfering RNA molecules inhibited IL-6-induced VSMC motility. Furthermore, balloon injury induced IL-6 expression both at mRNA and protein levels in rat carotid artery. Balloon injury also caused increased STAT-3 phosphorylation and cyclin D1 expression, leading to smooth muscle cell migration from the media to the intimal region. Blockade of gp130/STAT-3 signaling via adenovirus-mediated expression of dngp130 or dnSTAT-3 attenuated balloon injury-induced STAT-3 phosphorylation and cyclin D1 induction, resulting in reduced smooth muscle cell migration from media to intima and decreased neointima formation. Together, these observations for the first time suggest that IL-6/gp130/STAT-3 signaling plays an important role in vascular wall remodeling particularly in the settings of postangioplasty and thereby in neointima formation.