Systemic inflammation after drug-eluting stent placement

Study on the rationality of small diameter metallic airway stent in treatment of tracheal stenosis in injured rabbits

BACKGROUND

To observe the occurrence of related complications after self-expandable metallic (SEM) airway stents implantation with different diameters at different time points, and to provide theoretical basis for the optimal chioce of existing airway stents in clinical practice.

METHODS

Healthy New Zealand white rabbits were used to establish benign tracheal stenosis models after chest CT examination. Forty-fivemodel rabbits with more than 50% of airway stenosis were divided into two groups. Small-diameter SEM stents (The ratio of stent diameter to airway diameter is nearly 1.0) were implanted in Group A in 21 rabbits, and large-diameter tracheal stents (The ratio of stent diameter to airway diameter is more than 1.2) were implanted in Group B in 24 rabbits. Stent-related complications were observed after stent implantation in 2nd,4th,8th, and 12th week by bronchoscopygross anatomy, pathological and the expressions of IL-1RA, IL-8 and MMP9 in involved tracheal.

RESULTS

The incidence rate of tracheomalacia of stent was significantly higher in group B (24/24 100%) than that in group A (1 /21,4.8%) (P < 0.05). The incidence rate of scar contracture at both ends of stent was significantly higher than in group B (11 / 24,45.8%) that in group A (2 /21, 9.5%) (P < 0.05). The pathological results of both A and B showed that the columnar epithelium of bronchial mucosa began to damage and detach, inflammatory cells infiltrated after 2nd and 4th week of stenting, The epithelium was repaired, the lamina propria glands almost disappeared, collagen fiber proliferation was obvious, and scars were formed after 8th and 12th week of stenting. ELISA results revealed that the expressions of IL-1RA, IL-8, and MMP9 were increased in the stent group than in model rabbit with benign tracheal stenosis. IL-1RA and MMP9 increased at different periods in group B, but the expression of IL-1RA and MMP9 showed a tread of increasing in the early stage and then decreasing in group A.

CONCLUSION

Metal stents can cause different degrees of stent-related complications in rabbits with benign tracheal stenosis. The incidence of stent-induced tracheomalacia and scar contracture were higher in Group B than that in Group A. IL-1RA, IL-8 and MMP9 may be involved in the development of complications after stentimplantation and peak value of group B movered backward. ing.

Incidence of Restenosis Following Rapamycin or Paclitaxeleluting Stent in Coronary Stent Implantation

BACKGROUND & OBJECTIVES

Coronary artery disease (CAD) is chiefly characterized by atherosclerosis and plaque formation in coronary arteries. The aim of this study was to evaluate the correlation of coronary anatomy as a predictor of restenosis and stent thrombosis in coronary artery disease (CAD) patients 5 years after percutaneous coronary intervention (PCI).

METHODS

In this prospective study, 1070 patients with stent restenosis or stent thrombosis over past 5 years were enrolled. Coronary angiography was performed to evaluate coronary restenosis and stent thrombosis 5 years after PCI. Stent restenosis was defined as >50% angiographic in-stent lumen reduction. Stent thrombosis was defined as sudden complete occlusion of stent presenting with acute myocardial infarction in that territory. Demographic data, clinical features and anatomic factors were prospectively reviewed. Baseline, procedural, and post-procedural characteristics of patients were recorded for analysis.

RESULTS

Among demographic characteristics, cardiovascular risk factors (hypertension and diabetes mellitus) and anatomic factors were predictive risk factors for restenosis/thrombosis, p=0.001. The most common site for stent restenosis was proximal to the mid part of the LAD artery, followed by RCA and LCX. A greater diameter of LCX, a greater angle of LM-LAD than LM-LCX and left dominancy increase the incidence of LAD stent restenosis/thrombosis. In this study, the least common restenosis/thrombosis rate in relation to the total number of PCI was in the Ramus intermedius artery.

CONCLUSION

The outcomes of the study indicated that anatomic factors can predict increased risk of restenosis among CAD patients who underwent PCI.

Pathogenesis and Clinical Significance of In-Stent Restenosis in Patients with Diabetes

Diabetes mellitus (DM) is a strong risk factor for the development of cardiovascular diseases such as coronary heart disease, cerebrovascular disease, and peripheral arterial disease (PAD). In the population of people living with DM, PAD is characterised by multi-level atherosclerotic lesions as well as greater involvement of the arteries below the knee. DM is also a factor that significantly increases the risk of lower limb amputation. Percutaneous balloon angioplasty with or without stent implantation is an important method of the treatment for atherosclerotic cardiovascular diseases, but restenosis is a factor limiting its long-term effectiveness. The pathogenesis of atherosclerosis in the course of DM differs slightly from that in the general population. In the population of people living with DM, more attention is drawn to such factors as inflammation, endothelial dysfunction, platelet dysfunction, blood rheological properties, hypercoagulability, and additional factors stimulating vascular smooth muscle cell proliferation. DM is a risk factor for restenosis. The purpose of this paper is to provide a review of the literature and to present the most important information on the current state of knowledge on mechanisms and the clinical significance of restenosis and in-stent restenosis in patients with DM, especially in association with the endovascular treatment of PAD. The role of such processes as inflammation, neointimal hyperplasia and neoatherosclerosis, allergy, resistance to antimitotic drugs used for coating stents and balloons, genetic factors, and technical and mechanical factors are discussed. The information on restenosis collected in this publication may be helpful in planning further research in this field, which may contribute to the formulation of more and more precise recommendations for the clinical practice.

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.

Comprehensive analysis of predictive factors for rapid angiographic stenotic progression and restenosis risk in coronary artery disease patients underwent percutaneous coronary intervention with drug-eluting stents implantation

BACKGROUND

This study aimed to explore the correlation of baseline, procedural, and postprocedure characteristics with the risk of rapid angiographic stenotic progression (RASP) and restenosis in coronary artery disease (CAD) patients after percutaneous coronary intervention (PCI) with drug-eluting stents implantation.

METHODS

Two hundred fourteen CAD patients underwent PCI with drug-eluting stents implantation were consecutively enrolled. Baseline, procedural, and postprocedure characteristics of patients were collected for analysis. Coronary angiography was performed to evaluate coronary stenosis before PCI and at 12 months after PCI. RASP of nontarget lesions and restenosis of stent-implanted target lesions were then assessed.

RESULTS

37.8% CAD patients occurred RASP at 12 months after PCI and compared to non-RASP group, RASP group presented with increased diabetes mellitus (DM) complication, higher concentration of serum uric acid (SUA), cardiac troponin I, N-terminal probrain natriuretic peptide, and high sensitive C-reactive protein (hs-CRP) as well as elevated occurrence of multivessel artery lesions. In addition, DM, SUA, hs-CRP, and multivessel artery lesions independently predicted high RASP risk. For restenosis, 21.0% patients occurred restenosis at 12 months after PCI, and patients in restenosis group presented with increased hypertension and DM occurrence, higher concentrations of SUA, LDL-C, and hs-CRP, as well as longer target lesion and length of stent in surgery compared to nonrestenosis group. Also, DM, SUA, LDL-C, hs-CRP, and length of target lesion independently predicted increased restenosis risk.

CONCLUSION

Diabetes mellitus, SUA, and hs-CRP are potential predictive factors for increased risk of both RASP and restenosis in CAD patients underwent PCI and drug-eluting stents implantation.

Novel Multifunctional Nanomatrix Reduces Inflammation in Dynamic Conditions in Vitro and Dilates Arteries ex Vivo

Inflammatory responses play a critical role in tissue-implant interactions, often limiting current implant utility. This is particularly true for cardiovascular devices. Existing stent technology does little to avoid or mitigate inflammation or to influence the vasomotion of the artery after implantation. We have developed a novel endothelium-mimicking nanomatrix composed of peptide amphiphiles that enhances endothelialization while decreasing both smooth muscle cell proliferation and platelet adhesion. Here, we evaluated whether the nanomatrix could prevent inflammatory responses under static and physiological flow conditions. We found that the nanomatrix reduced monocyte adhesion to endothelial cells and expression of monocyte inflammatory genes (TNF-α, MCP-1, IL-1β, and IL-6). Furthermore, the nitric-oxide releasing nanomatrix dramatically attenuated TNF-α-stimulated inflammatory responses as demonstrated by significantly reduced monocyte adhesion and inflammatory gene expression in both static and physiological flow conditions. These effects were abolished by addition of a nitric oxide scavenger. Finally, the nanomatrix stimulated vasodilation in intact rat mesenteric arterioles after constriction with phenylephrine, demonstrating the bioavailability and bioactivity of the nanomatrix, as well as exhibiting highly desired release kinetics. These results demonstrate the clinical potential of this nanomatrix by both preventing inflammatory responses and promoting vasodilation, critical improvements in stent and cardiovascular device technology.

Urinary trypsin inhibitor reduced neointimal hyperplasia induced by systemic inflammation after balloon injury in rabbits

OBJECTIVES

The aims of this study were to evaluate the effect of urinary trypsin inhibitor (UTI) on the regulation of inflammatory cytokines induced by lipopolysaccharide (LPS) and the reduction of neointimal formation in rabbits.

METHODS AND RESULTS

Rabbits subjected to iliac artery balloon injury were randomly divided into three groups: control group (balloon injury), LPS group (LPS + balloon injury) and UTI group (UTI + LPS + balloon injury). Systemic markers of inflammation (serum IL-1β and TNF-α levels measured by ELISA) were increased after LPS administration. Arterial nuclear factor-κB (NF-κB/p65) at 28 days after injury was 31.50 ± 7.08 % of total cells in controls and 73.50 ± 6.90 % in LPS group (P < 0.05). Morphometric analysis of the injured arteries at 28 days revealed significantly increased luminal stenosis (45.81 ± 5.31 vs 27.93 ± 2.85 %, P < 0.05) and neointima-to-media ratio (1.40 ± 0.15 vs 0.68 ± 0.12, P < 0.05) in LPS-treated animals compared with controls. This effect was reduced by UTI administration. Serum IL-1β and TNF-α levels and NF-κB/p65 expression were significantly increased in correlation with the severity of intimal hyperplasia and inhibited by UTI.

CONCLUSIONS

Systemic inflammatory response concurrently with arterial vascular injury facilitated neointimal formation. UTI reduced neointimal hyperplasia by regulating inflammatory response and could be considered as a potential anti-restenosis supplement.

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.

Effectiveness of triptolide-coated stent on decreasing inflammation and attenuation of intimal hyperplasia in a pig after coronary angioplasty

OBJECTIVE

The study is to test the efficacy of triptolide-coated stent on anti-inflammatory and inhibiting intimal hyperplasia in preventing restenosis.

METHODS

A total of 15 triptolide-coated stents (TCSs), 12 drug-eluting stents (DESs), and 12 bare metal stents (BMSs) were deployed in porcine coronary arteries. Coronary angiography, histopathologic and inflammatory markers levels were analyzed at 4 week after stenting.

RESULTS

At 4-week follow-up, quantitative coronary angiography (QCA) showed that minimum lumen diameter was greater, and percentage stenosis and late lumen loss in TCS group and DES group were less than that of BMS group. Compared to BMS group, injury and inflammation score in TCS group and DES group were decreased, neointimal area significantly reduced and lumen area enlarged in TCS, DES group as well.

CONCLUSION

Triptolide-coated stent showed the effect of preventing restenosis via inhibition of neointimal hyperplasia and anti-inflammation acts after coronary angioplasty.

Elevated high sensitive C-reactive protein and apelin levels after percutaneous coronary intervention and drug-eluting stent implantation

OBJECTIVE

Percutaneous coronary intervention (PCI) triggers an acute inflammatory response, while sirolimus is known to have anti-inflammatory properties; the inflammatory system response to PCI after sirolimus-eluting stent placement remains unclear. The purpose of this study is to determine the changes in high sensitive C-reactive protein (hs-CRP) and apelin after PCI procedure and drug-eluting stent implantation in patients with and without reduced left ventricular systolic function.

METHODS

Forty-eight consecutive patients undergoing PCI at the Beijing Anzhen Hospital between July and September 2006 were recruited. Sirolimus-eluting stents were employed in all patients. Blood samples were drawn immediately before and 24 h after the procedure. Plasma hs-CRP and apelin levels were determined by enzyme immunoassay.

RESULTS

Paired t-test revealed a significant increase in both hs-CRP and apelin post-procedure (P=0.006 and P<0.0001, respectively). Patients with reduced left ventricular ejection fraction (LVEF) had significantly lower baseline apelin levels compared to those with normal ventricular function [(46.8+/-10.8) vs. (72.0+/-8.4) pg/ml, P<0.001]. However, apelin increased to a level similar to the level of those with normal left ventricular systolic function 24 h after the PCI procedure [(86.7+/-11.6) vs. (85.1+/-6.1) pg/ml, P=0.72].

CONCLUSIONS

hs-CRP and apelin levels increased after PCI and sirolimus-eluting stent implantation. Patients with impaired left ventricular systolic function had significantly lower baseline apelin levels, which increased significantly after PCI.

Serum Inflammatory and Immune Marker Response After Bare-Metal or Drug-Eluting Stent Implantation Following Percutaneous Coronary Intervention

We assessed the changes in serum antiheat shock protein (HSP)-27 antibody and high-sensitivity C-reactive protein (hsCRP) levels, following the placement of a drug-eluting stent (DES) or bare-metal stent (BMS) in patients with stable coronary artery disease. Either a BMS or DES was implanted in 137 patients (82 BMS; 55 DES). Anti-HSP27 and hsCRP levels were measured 24 hours before and 24 hours after stenting. Median hsCRP serum levels increased significantly to 60.78 (10.13-84.87) and 77.80 (50.00-84.84) mg/L for BMS and DES groups (P = .006 and P = .000, respectively); this increase did not differ significantly between the 2 groups. Median anti-HSP27 antibody levels decreased to 0.26 (0.17-0.49) and 0.21 (0.16-0.29) absorbency units in BMS and DES groups (P = .045 and P = < 0.001, respectively). The changes in anti-HSP27 antibody titers were significant between the 2 groups (P = .015). Bare-metal stent and DES differ in stimulation of immune rather than inflammatory responses. Less stent restenosis after DES compared with BMS implantation could, in part, be attributed to differences in immune responses.

Interleukin 8 gene polymorphisms and susceptibility to restenosis after percutaneous coronary intervention

Interleukin-8 is a strong mediator of inflammation and has been implicated in the biochemical pathways involved in a wide range of inflammatory diseases including atherosclerosis. We investigated the potential influence of two common functional polymorphisms of the interleukin (IL)-8 gene: -251A/T and 781C/T on susceptibility to in stent restenosis (ISR) following percutaneous coronary intervention (PCI). The hypothesis was tested by screening for the prevalence of the above polymorphisms in 201 coronary artery disease (CAD) patients subjected to PCI and presenting with symptoms or signs of recurrent ischemia. Patients were angiographically re-evaluated and formed the ISR group (n = 73) and the non-ISR group (n = 128) based on the presence or absence of ISR. One hundred and forty-seven subjects without angiographic evidence of CAD formed a reference control group (non-CAD group). A borderline statistically significant higher frequency of the TT(251)TT(781) combined genotype was observed in patients with ISR on re-evaluation compared with patients with normal follow-up angiography. The predominance of TT(251)TT(781) was independent of conventional risk factors for cardiovascular disease. Consequently, T(251)T(781) haplotype was significantly more common in the ISR group. The above observations indicate that the genetic diversity of the IL-8 gene influences patient susceptibility to ISR and suggests the implication of IL-8-mediated pathways in the process of ISR. However, the rarity of T(251)T(781) haplotype makes any clinical application of the above observations unfeasible.

Predictive value of C-reactive protein after drug-eluting stent implantation

During the last few decades, with the evolution of techniques and materials and the increasing experience of operators, percutaneous coronary interventions (PCI) have become an equally efficient alternative to coronary artery bypass grafts for the treatment of most coronary stenoses. Bare-metal stent implantation represented a major step forward, compared with plain old balloon angioplasty (POBA), by improving the immediate angiographic success. However, the incidence of in-stent restenosis (ISR) remained unacceptably high. Development of the drug-eluting stent (DES) significantly improved the outcome of PCI by dramatically abating the rate of ISR and reducing the incidence of target lesion revascularization. However, ISR has not been eliminated and the persistence of metal vessel scaffolding also raises concern regarding the occurrence of late or very late stent thrombosis. POBA and stent implantation have been shown to induce a local and systemic inflammatory response, whose magnitude is associated with worse clinical outcome, and they increase the risk of ISR. C-reactive protein, a marker of systemic inflammation, has been demonstrated to predict clinical and angiographic outcome after POBA or bare-metal stent implantation. However, conflicting data regarding the prognostic value of C-reactive protein following DES implantation are available. In this paper, we review the literature regarding the clinical and pathophysiological association between inflammation and prognosis after DES implantation and suggest some possible therapeutic approaches to reduce inflammatory burden with the aim to improve clinical and angiographic outcome after PCI.

Inflammatory protein levels and depression screening after coronary stenting predict major adverse coronary events

BACKGROUND

Traditional risk factors cannot account for the majority of future major adverse coronary events (MACE) in patients diagnosed with heart disease. We examined levels of inflammatory proteins to be possible predictors of future MACE and physiological and psychological factors that initiate temporal increases in inflammatory protein levels.

METHODS

Peripheral blood samples and depression data were collected 4 to 12 hr after elective coronary stent insertion in 490 patients. Depression screening was assessed by a single-question screening tool. Predictive modeling for future MACE was performed by using survival analysis, with time from the index event (placement of the stent) to future MACE as the dependent variable.

RESULTS

Patients with high-sensitivity c-reactive protein (hsCRP) in the second and third quartiles were 3 and 2.5 times more likely to have a MACE than patients with hsCRP in the first quartile, respectively. As levels of vascular cell adhesion molecule and monocyte chemoattractant protein-1 increased, so did the risk of future MACE. Patients who screened positive for depression were approximately 2 times more likely to have a MACE within 24 months after stent placement than were patients who did not screen positive.

CONCLUSIONS

Our results suggest that hsCRP, vascular cell adhesion molecule, and monocyte chemoattractant protein-1 levels, measured after coronary stent insertion in patients with coronary heart disease, are prognostic of future MACE. Furthermore, positive depression screening is an independent predictor of future MACE.

[Myonecrosis and inflammatory response following percutaneous coronary angioplasty. A protective role for betablockers?]

INTRODUCTION

Percutaneous coronary intervention (PCI) is widely used actually for the treatment of coronary disease. Stent implantation in the vessel wall is associated with local healing processes and some myonecrosis. However, little is known about the relationships between systemic inflammatory response, myonecrosis and the patient's and procedural characteristics.

OBJECTIVES

(i) To evaluate the level of C-Reactive Protein (hsCRP) and cardiac troponin I (cTnI) elevation after PCI; (ii) to determine the patient's and procedural factors associated with those elevations.

METHOD

This is a prospective monocentric study carried out in patients hospitalised for elective PCI or for ACS without cTnI elevation. CRP and cTnI were assessed before, after and 24 hours after the procedure.

RESULTS

Thirty-four patients (mean age 64+/-10.9 years; sex ratio 28 males/six females) were included. hsCRP increased in 26 patients (76.4%) and cTnI in 16 patients (47%) after PCI. cTnI elevation did not correlate with inflammatory response. Whereas none of the studied parameters were statistically linked with hsCRP increase, cTnI elevation was significantly associated with AHA-ACC B(2)/C type lesion, the number and the total length of stents implanted, the duration of procedure and treatment by betablockers. Multivariate analysis showed that the independent predictors of cTnI elevation were procedure duration (p=0.032 OR=14.2 CI 95% 7.69-100) and the absence of pretreatment with betablockers (p=0.036, OR=2,6 CI 95% 1.35-35).

CONCLUSION

cTnI elevation following PCI is very frequent and related with the duration of the procedure. Our data suggest a protective role of betablockers in the occurrence of cTnI elevation after PCI. Confirmation of the protective role of betablockers in larger cohort is mandatory.

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.

Innate immunity has a dual effect on vascular healing: suppression and aggravation of neointimal formation and remodeling post-endotoxin challenge

BACKGROUND

Inflammation is important to vascular repair following injury, modulating neointimal proliferation and remodeling. Previously, we have shown that a low-intensity inflammatory response aggravates neointimal formation following balloon and stent injury. The present study examined whether modulation of the extent and timing of nonspecific inflammation mediates the local vascular response in an additive unidirectional or rather a bidirectional fashion.

METHODS AND RESULTS

Rabbits subjected to denudation and balloon injury of the iliac artery were treated with low (1 microg/kg) or high (100 microg/kg) doses of bacterial endotoxin (LPS) immediately after injury, or with early high-dose LPS administered 3 days prior to injury (preconditioning). Neointimal formation at 28 days was significantly increased in the low-dose group (0.537+/-0.059 mm(2)) as compared with controls (0.3+/-0.03 mm(2)). High-dose LPS did not significantly affect neointimal formation while early high dose significantly reduced neointima (0.296+/-0.033 and 0.194+/-0.025 mm(2), respectively, n=12-14/group). Arterial wall and systemically circulating interleukin-1 beta levels, and monocyte CD14 activation correlated with neointimal formation. Vascular remodeling was accelerated in animals treated with low- or high-dose LPS while not affected in the preconditioned group. Remodeling index inversely correlated with arterial matrix metalloproteinase-2 levels 6 days after injury.

CONCLUSIONS

The extent and timing of nonspecific inflammation that is concurrent with vascular injury can determine different and opposite vascular repair patterns.

Leukocyte activation after coronary stenting in patients during the subacute phase of a previous ST-elevation myocardial infarction

OBJECTIVE

To study leukocyte activation after percutaneous coronary intervention in patients with previous ST elevation myocardial infarction.

METHODS

Neutrophil and monocyte activation (by flow cytometric assessment of the surface expression of CD11b and CD62L adhesion molecules) was assessed in 39 patients during the subacute period of a previous ST elevation myocardial infarction initially treated with fibrinolytic agents, before and after diagnostic coronary angiography (coronary angiography control phase) as well as before and after stent implantation (percutaneous coronary intervention phase). Simultaneous evaluation of C-reactive protein (C-reactive protein immonoturbidimetry) and plasma cytokine levels (interleukins-1, -6, -10 and tumor necrosis alpha by immunoassay) was also performed. To track the earliest detectable change in the first few minutes after stent deployment, all measurements were performed before and 60 min after the procedures.

RESULTS

CD11b expression increased 1 h after stent deployment in neutrophils (P<0.0001) and monocytes (P<0.0001). A comparable increase, however, was also observed after coronary angiography (neutrophils, P=0.03; monocytes, P=0.01), although the increase of CD11b expression was greater after percutaneous coronary intervention on both neutrophils (90 vs. 40%, P=0.014) and monocytes (65 vs. 33%, P=0.04). CD62L expression decreased significantly after percutaneous coronary intervention (neutrophils, P=0.01; monocytes, P=0.006), but remained unchanged after coronary angiography. Plasma cytokine and C-reactive protein concentrations did not change after the procedures.

CONCLUSION

CD62L appears to be a specific and reliable early cellular biomarker of leukocyte activation after percutaneous coronary intervention, when this procedure is performed in patients with previous ST elevation myocardial infarction. Whether this marker represents also a potential predictor of future events and/or restenosis in this group of patients remains to be defined.

Reduced systemic inflammatory response to implantation of sirolimus-eluting stents in patients with stable coronary artery disease

Stent implantation causes significant injury to the vascular wall, resulting in inflammatory activation. Although sirolimus-eluting stents (SES) have anti-inflammatory properties, their effect on periprocedural systemic inflammatory response has not been sufficiently investigated. Eighty-one patients with stable coronary artery disease involving severe stenosis of one major epicardial coronary artery underwent coronary angioplasty with stent implantation and randomly received either SES or bare metal stents (BMS). Blood samples were taken 24h before, at 24h, 48 h and 1 month after the angioplasty and levels of high sensitive C-reactive protein (hsCRP), interleukin-6 (IL-6), interleukin-1 beta (IL-1 beta), and monocyte chemoattractant protein-1 (MCP-1) were determined. HsCRP after BMS implantation increased over 24h (p<0.001) and then remained steady, as did IL-6 and IL-1 beta similarly. In contrast, their levels in SES patients decreased to below baseline by the end of the month. MCP-1 levels increased by the end of 1 month (p<0.001) in the BMS group, whereas in SES they steadily decreased, becoming significantly lower than baseline from 48 h (p=0.015). In conclusion, patients with SES exhibit an attenuation of the postprocedural systemic inflammatory activation during a 1-month follow-up after stent implantation. This might partially explain the reduced restenosis rate associated with SES.

Inflammatory Cytokine Imbalance after Coronary Angioplasty: Links with Coronary Atherosclerosis

AIM

To investigate release of some inflammatory cytokines (Cys) after coronary angioplasty and its links with coronary atherosclerosis.

METHODS

Twenty-seven consecutive subjects with acute coronary syndrome (ACS) who underwent percutaneous coronary intervention (PCI) were enrolled in the study: serial blood samples were taken in order to evaluate plasma concentrations of Interleukin (IL)-2, IL-10, IL-18, TNFalpha, and IFNgamma just before PCI at 12 and 24 hours. Patients were then divided, considering balance between each inflammatory Cy and IL-10, an antiinflammatory Cy, into four groups, ranging from a prevalent antiinflammatory response (stable inflammatory Cy-increasing IL-10 values) to a marked inflammatory imbalance (increasing inflammatory Cy-stable IL-10 values).

RESULTS

All Cys showed significant increases in plasma concentrations if compared with baseline values. Release curves were not significantly different when comparing subjects with ST-elevation myocardial infarction (STEMI) versus unstable angina-non-STEMI (UA-NSTEMI), diabetics versus controls. Subjects with marked inflammatory response showed a higher incidence of stenosis on left anterior descending (LAD) coronary artery (IL-2 chi(2) and IFNgamma P < 0.05); Cy release was higher in patients with multivessel coronary disease (IL-2 and IFNgamma, ANOVA P < 0.01). Correlations were also referable between Cys and myocardial enzyme release. Subjects treated with sirolimus-eluting stents (SES) showed significantly lower Cy periprocedure ratio if compared with those treated with bare metal stents.

CONCLUSIONS

A significant Cy release is detectable after PCI: inflammatory response seems to correlate with both PCI due to plaque instabilization and coronary atherosclerosis. A blunted inflammatory response is detectable in subjects treated with SES.

Osteoprotegerin is not associated with angiographic coronary calcification

Coronary artery calcification may play a significant role in the pathophysiology of plaque progression and healing. We hypothesized that osteoprotegerin, an inhibitor of osteoclastogenesis, may participate in the calcification of coronary plaques or the response to injury after coronary stenting. A prospective registry was performed in 2004. Blood samples from 100 patients undergoing percutaneous coronary intervention (PCI) were obtained before PCI and 24 h after PCI. The concentrations of osteoprotegerin (OPG), C-reactive protein, interleukin-6, and soluble CD40 ligand (sCD40L) were determined by ELISA. Quantitative coronary angiography was performed to define the presence of culprit lesion calcification (CLC). Comparisons among markers of inflammation and tertiles of OPG were stratified with respect to CLC. Patients with CLC (n = 28) compared with no CLC (n = 71) were older (P < 0.01), had lower creatinine clearance (P < 0.01), lower hemoglobin (P = 0.02), and were less likely to smoke (P = 0.04). Patients without CLC were over twice as likely to present with a marker-positive acute coronary syndrome. CLC was associated with less pre-PCI platelet-mediated inflammation as measured by sCD40L (4.65 vs. 7.15 pg/ml, P = 0.05), but not with lower levels of OPG. Inflammatory cytokines increased significantly after PCI for patients with and without CLC. For patients in the highest tertile of OPG at baseline, there was a reduction in OPG after PCI. Systemic osteoprotegerin levels are not associated with angiographic calcification of culprit plaques. For patients with elevated levels of OPG prior to PCI, there is a significant reduction after PCI consistent with a counterregulatory role for OPG.

CONDENSED ABSTRACT

Both calcified and non-calcified culprit plaques exhibited a similar inflammatory response to stent-mediated injury. After PCI, osteoprotegerin decreased while proinflammatory cytokines increased, which may be consistent with a counterregulatory role for osteoprotegerin.

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.

Is inflammation a contributor for coronary stent restenosis?

The development of coronary stent has revolutionized the field of interventional cardiology by reducing the incidence of restenosis after balloon angioplasty. Despite significant progress in its prevention and treatment, however, in-stent restenosis (ISR) is still common, and remains a challenge for the interventional cardiologist. Restenosis after stent implantation is mainly caused by neointimal proliferation through the stent struts. Currently, there are three major factors has been demonstrated to be contributors for ISR, namely patients-, lesion- and genetic-related factors in large number of clinical trials. However, the triggers and pathophysiological mechanisms for ISR are not fully elucidated. Experimental as well as clinical studies indicate a marked activation of inflammatory cells at the site of stent structs, which are likely to play a key role in the process of neointimal proliferation and stent restenosis. Those data suggest that inflammation may be a major contributor for ISR. In fact, coronary stenting is a strong inflammatory stimulus and the acute systemic response to local inflammation produced by coronary stenting is highly individual and predicts restenosis and event-free survival. Thus, the attention should be paid on anti-inflammatory therapeutic approaches for ISR, and the benefit of anti-inflammatory therapy during the periprocedural period and long-term follow-up is dependent on the inflammatory status. 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.