Granulocyte activation after coronary angioplasty in humans

The role of renin-angiotensin system activated phagocytes in the SARS-CoV-2 coronavirus infection

OBJECTIVE

Management of the pandemic caused by the novel coronavirus SARS-CoV-2 challenges both scientists and physicians to rapidly develop, and urgently assess, effective diagnostic tests and therapeutic interventions. The initial presentation of the disease in symptomatic patients is invariably respiratory, with dry cough being the main symptom, but an increasing number of reports reveal multiple-organ involvement. The aim of this review is to summarize the potential role of the renin-angiotensin system activated phagocytes in the pathogenesis of COVID-19 disease.

METHODS

Data for this review were identified by searches of PubMed and references from relevant articles using the search terms "SARS," "COVID-19," "renin-angiotensin-system," "phagocyte," "reactive free radical," "antioxidant," "ARDS," "thrombosis," "myocardial," "ischaemia," "reperfusion," "microvascular," and "ACE2." Abstracts and reports from meetings were not included in this work. Only articles published in English between 1976 and 2020 were reviewed.

RESULTS

The cellular target of SARS viruses is the angiotensin-converting enzyme 2, a critical regulating protein in the renin-angiotensin system. The elimination of this enzyme by the viral spike protein results in excessive activation of phagocytes, migration into the tissues via the high endothelial venules, and an oxidative burst. In the case of an overstimulated host immune response, not only devastating respiratory symptoms but even systemic or multiorgan involvement may be observed.

CONCLUSIONS

Early-stage medical interventions may assist in returning the exaggerated immune response to a normal range; however, some therapeutic delay might result in excessive tissue damages, occasionally mimicking a systemic disease with a detrimental outcome.

Arterial smooth muscle dynamics in development and repair

Arterial vasculature distributes blood from early embryonic development and provides a nutrient highway to maintain tissue viability. Atherosclerosis, peripheral artery diseases, stroke and aortic aneurysm represent the most frequent causes of death and are all directly related to abnormalities in the function of arteries. Vascular intervention techniques have been established for the treatment of all of these pathologies, yet arterial surgery can itself lead to biological changes in which uncontrolled arterial wall cell proliferation leads to restricted blood flow. In this review we describe the intricate cellular composition of arteries, demonstrating how a variety of distinct cell types in the vascular walls regulate the function of arteries. We provide an overview of the developmental origin of arteries and perivascular cells and focus on cellular dynamics in arterial repair. We summarize the current knowledge of the molecular signaling pathways that regulate vascular smooth muscle differentiation in the embryo and in arterial injury response. Our review aims to highlight the similarities as well as differences between cellular and molecular mechanisms that control arterial development and repair.

Adenosine Production by Biomaterial-Supported Mesenchymal Stromal Cells Reduces the Innate Inflammatory Response in Myocardial Ischemia/Reperfusion Injury

BACKGROUND

During myocardial ischemia/reperfusion (MI/R) injury, there is extensive release of immunogenic metabolites that activate cells of the innate immune system. These include ATP and AMP, which upregulate chemotaxis, migration, and effector function of early infiltrating inflammatory cells. These cells subsequently drive further tissue devitalization. Mesenchymal stromal cells (MSCs) are a potential treatment modality for MI/R because of their powerful anti-inflammatory capabilities; however, the manner in which they regulate the acute inflammatory milieu requires further elucidation. CD73, an ecto-5'-nucleotidase, may be critical in regulating inflammation by converting pro-inflammatory AMP to anti-inflammatory adenosine. We hypothesized that MSC-mediated conversion of AMP into adenosine reduces inflammation in early MI/R, favoring a micro-environment that attenuates excessive innate immune cell activation and facilitates earlier cardiac recovery.

METHODS AND RESULTS

Adult rats were subjected to 30 minutes of MI/R injury. MSCs were encapsulated within a hydrogel vehicle and implanted onto the myocardium. A subset of MSCs were pretreated with the CD73 inhibitor, α,β-methylene adenosine diphosphate, before implantation. Using liquid chromatography/mass spectrometry, we found that MSCs increase myocardial adenosine availability following injury via CD73 activity. MSCs also reduce innate immune cell infiltration as measured by flow cytometry, and hydrogen peroxide formation as measured by Amplex Red assay. These effects were dependent on MSC-mediated CD73 activity. Finally, through echocardiography we found that CD73 activity on MSCs was critical to optimal protection of cardiac function following MI/R injury.

CONCLUSIONS

MSC-mediated conversion of AMP to adenosine by CD73 exerts a powerful anti-inflammatory effect critical for cardiac recovery following MI/R injury.

Decreased Antioxidant Vitamin Concentration May Be a Risk Factor for Recurrent Carotid Stenosis

Carotid endarterectomy has been found to be associated with a transient increase in systemic oxidative stress, and this has been shown to be a predictor of restenosis. The aim of this study was to determine the incidence of early recurrent stenosis and investigate a possible role of oxidative stress in its development by measuring the concentration of antioxidant vitamins. Patients undergoing carotid endarterectomy between August 2001 and February 2003 were included in the study. A preoperative blood sample was analyzed for antioxidant vitamin concentrations. All patients were followed up by duplex scans 3 and 12 months postoperatively. Ninety-three patients (101 carotid endarterectomies) were recruited. Nine arteries had developed restenosis by 12 months. Those patients who developed recurrent stenosis had significantly lower vitamin C concentrations (19.10 ± 3.69 vs 30.11 ± 19.10, P = .02) than those who did not. This study suggests that low antioxidant vitamin levels may predispose to early restenosis after carotid endarterectomy.

Eosinophil count is positively correlated with coronary artery calcification

Recent studies suggested that allergic disorders and increased eosinophil count were associated with atherosclerosis. The purpose of this study was to assess the relationship between eosinophil count and coronary artery calcification (CAC). We performed a cross-sectional study in 1363 consecutive participants with clinical suspicion of coronary heart disease (CHD). We evaluated the relationships between CAC score determined by multislice CT and peripheral eosinophil count as well as major cardiovascular risk factors, including age, body mass index, smoking status, hypertension, dyslipidemia, diabetes mellitus (DM), high-sensitivity C-reactive protein and estimated glomerular filtration rate (eGFR). Sex (P=0.0004), hypertension (P=0.0002), dyslipidemia (P=0.0004) and DM (P=0.0061) were associated with log(CAC+1), respectively. Positive correlations were found between log(CAC+1), and age (r=0.325, P<0.0001) and eosinophil count (r=0.165, P<0.0001). Negative correlations were found between log(CAC+1) and eGFR (r=-0.166, P<0.0001). Multivariate linear regression analysis demonstrated that age (β=0.314, P<0.0001), sex (β=0.124, P<0.0001), hypertension (β=0.084, P=0.0008), DM (β=0.108, P<0.0001), eGFR (β=-0.079, P=0.0021) and eosinophil count (β=0.147, P<0.0001) were independent determinants of log(CAC+1). In conclusion, eosinophil count correlated positively with CAC in participants with clinical suspicion of CHD.

Sulfido-peptide leukotrienes in coronary heart disease - relationship with disease instability and myocardial ischaemia

BACKGROUND

Urinary excretion of leukotriene (LT) E(4) is an index of LTC(4) biosynthesis and platelet-neutrophil interactions, which may occur in coronary heart disease and contribute to myocardial ischaemia. Enhanced LTC(4) biosynthesis may be a consequence of myocardial ischaemia or be linked to its pathogenetic substrate.

METHODS AND RESULTS

Overnight urine collections were obtained from 17 patients with chronic stable angina, three patients with Prinzmetal's angina, 16 patients with non ST-elevation acute coronary syndromes (NSTE-ACS) and six patients with acute ST-elevation myocardial infarction (STEMI). LTE(4) excretion was measured by enzyme immunoassay after HPLC separation. Compared with healthy controls (51.1 +/- 21.3 pg mg(-1) creatinine, mean +/- SD, n = 11) and with non-coronary cardiac controls (36.6 +/- 9.8 pg mg(-1) creatinine, n = 9), LTE(4) excretion was unchanged in stable angina (40.5 +/- 25.8 pg mg(-1) creatinine), but significantly (P < 0.01) increased in NSTE-ACS (122.7 +/- 137.2 pg mg(-1) creatinine) and STEMI (213.4 +/- 172.4 pg mg(-1) creatinine). In these patients, LTE(4) excretion rapidly dropped after day 1, consistent with effective coronary reperfusion. In patients with NSTE-ACS, the increase in LTE(4) excretion was entirely restricted to patients with recent (< 48 h) spontaneous anginal episodes. Myocardial ischaemia elicited by a positive exercise stress test was not accompanied by any detectable increase in LTE(4) excretion, while a significant (P < 0.01) increase was detected after a single-vessel percutaneous coronary interventions (PCI) procedure (n = 10), as compared with diagnostic angiography (n = 9).

CONCLUSIONS

In coronary heart disease, increased LTC(4) biosynthesis is restricted to ACS and not linked to myocardial ischaemia per se, but likely to the occurrence of plaque disruption.

Coronary stenting is associated with an acute increase in plasma myeloperoxidase in stable angina patients but not in patients with acute myocardial infarction

BACKGROUND

Myeloperoxidase (MPO) has emerged as a critical mediator in the physiopathology of atherosclerosis from plaque formation and growth until destabilization and rupture leading to acute coronary syndrome (ACS). Using coronary stenting as a model of plaque injury, we aimed to determine the evolution of systemic MPO levels following coronary stenting in stable angina patients and in patients with acute myocardial infarction (AMI).

METHODS

Plasma levels of MPO, lactoferrin, interleukin (IL)-6, C-reactive protein and PMN counts were assessed in 13 patients with Non-ST-elevation myocardial infarction (NSTEMI) (Group A) and in 29 patients with stable angina pectoris (Group B), undergoing coronary stenting. Serial blood samples were taken before angioplasty (baseline) and at 1, 6 and 24 h following initial balloon inflation.

RESULTS

Following angioplasty, the overall plasma MPO levels significantly increased at 1 h in group B (120.5+/-79.0 to 166+/-79.5, p=0.003) but not in group A (121+/-63.4 to 124.7+/-76.9, p=0.753). In Group B, the increase in MPO levels at 1 h were significantly higher in the presence of complex lesions compared to patients with simple lesions (p=0.023). Lactoferrin levels showed no change over time except for a significant decrease at 6 h in group B.

CONCLUSIONS

In stable angina patients, coronary stenting is associated with an acute and transient increase in plasma MPO levels, but not in lactoferrin levels, with an enhanced response in the presence of complex lesions. In contrast, we observed no changes in plasma MPO and lactoferrin levels following stenting in patients with AMI. Given its pro-inflammatory properties, the potential implication of MPO release on clinical outcome in stable patients undergoing stenting needs further investigation.

Atrial natriuretic peptide increases inflammation, infarct size, and mortality after experimental coronary occlusion

Acute coronary artery occlusion triggers the release of atrial natriuretic peptide (ANP) from the heart. ANP affects vasodilation, natriuresis, and inflammation, but the integrated biological effects of ANP on myocardial infarction are unknown. To elucidate these effects, the left anterior coronary artery was ligated in anesthetized, ANP-deficient (ANP(-/-)) and congenic wild-type (ANP(+/+)) mice. The survival of ANP(-/-) mice was markedly better (56%) at 30 days postinfarction than the survival of ANP(+/+) mice (20%, P < 0.01). Surviving mice were comparable initially, but ANP(-/-) mice developed more cardiac hypertrophy (P < 0.001) and had lower contractility indexes 30 days after infarction (P < 0.05). An analysis 24 h after coronary occlusion showed that ANP(-/-) mice had smaller infarcts than ANP(+/+) mice (62.6 +/- 12.1 vs. 100.8 +/- 3.8%, P < 0.001) adjusted for comparable areas at risk for ischemia. The administration of ANP to ANP(-/-) mice via osmotic minipumps significantly enlarged infarct size to levels comparable with those observed in ANP(+/+) mice (P < 0.05). There was no difference in neutrophil migration into the noninfarcted myocardium of ANP(-/-) mice undergoing actual versus sham-operated coronary occlusion. By comparison, after coronary occlusion, the neutrophil infiltration into the myocardium was enhanced in ANP(+/+) (P < 0.0005) and ANP(-/-) mice administered ANP (P < 0.0005). The expression of P-selectin, a molecule that mediates neutrophil adhesion, was significantly greater after coronary occlusion in the vasculature of ANP(+/+) or ANP(-/-) mice treated with ANP than in ANP(-/-) mice (P < 0.002). Taken together, these results indicate that ANP increases P-selectin, neutrophil infiltration, infarct size, and mortality following experimental coronary occlusion.

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.

Increased circulating platelet-derived microparticles are associated with stent-induced vascular inflammation

Inflammation as well as platelet activation at the site of local vessel-wall injury plays an essential role in the mechanism of restenosis after Percutaneous coronary intervention (PCI). Platelet-derived microparticles (PDMPs) released from activated platelets are thought to play a role in the inflammatory process, possibly interacting with leukocyte integrin Mac-1. We serially measured circulating PDMPs, high-sensitive C-reactive protein (hs-CRP) and activated Mac-1 on the surface of neutrophils in 61 patients undergoing coronary stenting. PDMPs, hs-CRP and Mac-1 increased after coronary stenting in a time-dependent manner with the maximum response at 48 h in coronary sinus blood (PDMPs: 10.3+/-8.9-32.8+/-13.8 U/ml; P<0.001, hs-CRP: 0.27+/-0.23-1.46+/-0.99 mg/dl; P<0.001, activated Mac-1, 134+/-19% relative increase, P<0.001). PDMPs were correlated with hs-CRP (R=0.58, P<0.001) and the relative increase in Mac-1 (R=0.69, P<0.001) 48 h after coronary stenting. Multiple regression analysis showed that each of PDMPs (R=0.40, P<0.05), hs-CRP (R=0.33, P<0.05) and Mac-1 (R=0.48, P<0.01) was an independent predictor of the late lumen loss. Coronary stenting enhanced circulating PDMPs in association with an inflammatory response in the injured vessel wall. PDMPs may be a useful marker for evaluation of stent-induced inflammatory status and a powerful predictor of restenosis equivalent to activated Mac-1.

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.

Antioxidant vitamins reduce oxidative stress and ventricular remodeling in patients with acute myocardial infarction

We analyzed soluble vascular adhesion molecules (sVCAM-1), reactive oxygen metabolites (ROMs) level, total antioxidant status (TAS) and telediastolic left ventricular volume (TLVV) in patients with myocardial infarction undergoing reperfusion therapy and treated with antioxidant vitamins (AT) or placebo (P) before and for 1 month after reperfusion. After reperfusion, sVCAM-1 serum concentration, reactive oxygen metabolites level, and TLVV were significantly higher in patients treated with placebo than in those treated with antioxidant vitamins, while TAS was significantly higher in patients treated with antioxidant supplementation. We observed that 48 hours after reperfusion sVCAM-1 (P) vs sVCAM-1 (AT) was 2.03+/-0.5 vs 1.63+/-0.7 microg/ml with p < 0.01; ROMs (P) vs ROMs (AT) were 335.60+/-35.80 vs 307.50+/-47.10 U.CARR with p < 0.05; TAS (P) vs TAS (AT) was 526.47+/-44.24 vs 737.65+/-51.15 micromol/l with p < 0.01; 1 week after reperfusion TLVV (P) vs TLVV (AT) was 125.12+/-29.80 vs 119.40+/-29.40 ml with p < 0.05; 1 month after reperfusion TLVV (P) vs TLVV (AV) was 132.00+/-33.50 vs 123.40+/-21.60 ml with p < 0.05. In the first period after infarction, vitamin treatment improves the antioxidant system and reduces oxidative stress, inflammatory process and left ventricular remodeling.

Acute neutrophil activation in direct stenting: comparison of stable and unstable angina patients

BACKGROUND

Polymorphonuclear neutrophils have been implicated in the pathophysiology of atherosclerosis. A substantial body of evidence has emerged to implicate the role of specific leucocyte derived enzyme myeloperoxidase in atherogenesis, since its initiation through progression until destabilization. The aim of the study was to determine the presence of polymorphonuclear neutrophils activation after coronary stenting, to compare this activation between stable and unstable setting and to evaluate the kinetic relation of this activation with inflammatory response following atherosclerotic plaque rupture.

METHODS

Myeloperoxidase, lactoferrin, elastase, C-reactive protein and cytokine plasma levels were assessed in 15 patients undergoing direct coronary stenting for unstable angina (Group A) and compared to 11 patients undergoing this procedure for stable angina (Group B). Serial sampling starting before arteriography and continued for 24 h was carried out in all patients.

RESULTS

A significant elevation in myeloperoxidase and lactoferrin levels was observed after stenting in both group A (p<0.0001) and group B (p<0.0001), but was higher in group A. Interleukin-8, interleukin-12 and interleukin-6 levels increased temporarily after stenting in the 2 groups. Baseline values of C-reactive protein were similar in the 2 groups and a progressive increase was observed after the intervention.

CONCLUSIONS

Direct coronary artery stenting is associated with an early polymorphonuclear neutrophils activation followed by release of inflammatory cytokines (interleukin-6, interleukin-8, interleukin-12) and C-reactive protein elevation in both stable and unstable patients. We conclude that stenting by itself is associated with myeloperoxidase liberation with a significantly enhanced response in unstable patients.

Neutrophils superoxide anion generation during carvedilol therapy in patients with stable angina

Neutrophil superoxide anion (O(2)(*-)) generation was measured during carvedilol therapy in patients with stable angina. The carvedilol group comprised 27 patients (18 men and 9 women), aged 38-51 years (mean 47.6 years) with stable angina. Carvedilol was administered in increased every 4-week doses: 12.5, 25 and 50 mg/24 h, respectively. The control group included 12 healthy subjects, aged 39-49 years (mean 45.7 years) with no drug administered. Blood samples were collected from cubital vein before and 4, 8 and 12 weeks after the therapy and once in the control group. Neutrophil O(2)(*-) generation was determined in whole blood without and with opsonized zymosan (OZ) stimulation according to Bellavite et al. method using superoxide dismutase from bovine erythrocytes. O(2)(*-) generation by nonstimulated and OZ-stimulated neutrophils was significantly higher (p<0.05) in patients with stable angina than in the control group. In carvedilol group, statistically significant (p<0.05) decrease in superoxide anion generation by nonstimulated and OZ-stimulated neutrophils was observed 8 and 12 weeks after the therapy and it did not differ from that in healthy subjects. Carvedilol has been shown to inhibit neutrophil O(2)(*-) generation in patients with stable angina.

Local Release of C-Reactive Protein From Vulnerable Plaque or Coronary Arterial Wall Injured by Stenting

OBJECTIVES

The purpose of this study was to assess local release of C-reactive protein (CRP) from atherosclerotic plaques or the vessel wall injured by stenting.

BACKGROUND

Recent research has focused on the local production of CRP, especially in inflammatory atherosclerotic plaques.

METHODS

The study consisted of two separate protocols. In protocol 1, we measured serum high-sensitivity-CRP (hs-CRP) levels in coronary arterial blood sampled just distal and proximal to the culprit lesions in 36 patients with stable angina and 13 patients with unstable angina. In protocol 2, we measured serial serum hs-CRP levels and activated Mac-1 on the surface of neutrophils in both coronary sinus and peripheral blood in 20 patients undergoing coronary stenting.

RESULTS

In protocol 1, CRP was higher in distal blood than proximal blood in both stable (p < 0.05) and unstable angina (p < 0.01). The translesional CRP gradient (distal CRP minus proximal CRP, p < 0.05) as well as the proximal CRP (p < 0.05) and distal CRP (p < 0.05) was higher in unstable angina than in stable angina. In protocol 2, the transcardiac CRP gradient (coronary sinus minus peripheral blood) and activated Mac-1 increased gradually after stenting, reaching a maximum at 48 h (p < 0.001 vs. baseline for both). There was a positive correlation between the transcardiac CRP gradient and activated Mac-1 at 48 h (r = 0.45, p < 0.01).

CONCLUSIONS

C-reactive protein is an excellent marker for plaque instability or poststent inflammatory status, and its source might be the inflammation site of the plaque or the coronary arterial wall injured by stenting.

Prevention of restenosis after stenting: the emerging role of inflammation

Restenosis after stent implantation is mainly caused by neointimal proliferation through the stent struts. Experimental studies indicate a marked activation of inflammatory cells at the site of stent struts, which are likely to play a key role in the process of neointimal proliferation and restenosis. Coronary stenting is a strong inflammatory stimulus and the acute systemic inflammatory response to local inflammation produced by coronary stenting is highly individual and predicts restenosis and event-free survival. 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, may be important to identify high-risk subjects and develop specific treatment tailored to the individual patient.

Early release of neutrophil markers of activation after direct stenting in patients with unstable angina

OBJECTIVE

To assess polymorphonuclear neutrophils activation after stenting in acute coronary syndromes studied by myeloperoxydase, lactoferrin and elastase release in this clinical setting.

METHODS

Myeloperoxydase, lactoferrin, elastase, C-reactive protein and cytokines serum levels were assessed in 20 patients undergoing catheterization for unstable angina. Serial sampling starting before arteriography and continued up to 24 h was carried out in 15 patients undergoing direct stenting (group A) and in five patients assessed by coronary angiography only (group B).

RESULTS

Myeloperoxydase, lactoferrin and elastase levels remained unchanged following catheterization, whereas a significant increase in myeloperoxydase (P = 0.0009) and lactoferrin (P = 0.004) was observed after stenting. No change in levels of tumour necrosis factor alpha, interleukin (IL)-8 and IL-11 was found in group B after catheterization at the different sampling times, although IL-8 and IL-11 levels increased transiently following stenting. IL-6 values increased in both groups. Baseline values of C-reactive protein were similar in each group. A progressive increase in C-reactive protein was noted in both groups and appeared to be larger following stenting (group A: P = 0.0002; group B: P = 0.01).

CONCLUSIONS

In patients with unstable angina, stenting is associated by immediate neutrophil activation followed by release of inflammatory cytokines (IL-6, IL-8, IL-11) and C-reactive protein elevation. This study points out a potential role of myeloperoxydase as a trigger for inflammatory reaction in patients with unstable coronary syndromes undergoing percutaneous coronary intervention.

Cilostazol inhibits leukocyte integrin Mac-1, leading to a potential reduction in restenosis after coronary stent implantation

OBJECTIVES

The aim of this study was to confirm clinically a hypothesis that cilostazol inhibits leukocyte Mac-1, leading to prevention of post-stent restenosis.

BACKGROUND

The platelet phosphodiesterase III inhibitor called cilostazol also inhibits alpha-granule release of P-selectin in platelets. The P-selectin-mediated platelet-leukocyte interaction promotes activation and upregulation of leukocyte Mac-1 after coronary stenting, which plays a key role on the mechanism of restenosis. Thus, cilostazol's potential inhibition of this process may lead to prevention of restenosis.

METHODS

Using flow cytometric analysis of whole blood obtained from the coronary sinus, the expression of platelet membrane glycoproteins and neutrophil adhesion molecules was observed in 70 consecutive patients undergoing coronary stenting. The patients were randomly assigned to either a cilostazol or ticlopidine group before stent placement.

RESULTS

The restenosis rate was lower (15% vs. 31%, p < 0.05) in the cilostazol group (n = 34) than in the ticlopidine group (n = 32). A stent-induced increase in platelet P-selectin (CD62P) expression and an increase in neutrophil Mac-1 (CD11b) expression were suppressed in the cilostazol group compared with the ticlopidine group. Angiographic late lumen loss was correlated with the relative changes in platelet P-selectin and neutrophil Mac-1 at 48 h after coronary stenting.

CONCLUSIONS

Cilostazol may have effects on suppression of P-selectin-mediated platelet activation, platelet-leukocyte interaction, and subsequent Mac-1-mediated leukocyte activation, which might lead to a reduced restenosis rate after coronary stent implantation.

C-reactive protein and immunoglobulin-E response to coronary artery stenting in patients with stable angina

Recent reports indicate that inflammatory mechanisms play a crucial role in the pathogenesis of atherosclerosis and neointimal proliferation as well as coronary restenosis. To provide baseline data for further studies regarding stenting, restenosis and inflammatory response. we prospectively conducted a clinical study to investigate the time related response of plasma levels of immunoglobulin-E (IgE) and C-reactive protein (CRP) which are two different inflammatory markers mediated by different cytokines in stable patients who underwent elective coronary artery stenting. Thirteen consecutive stable patients who underwent coronary artery stenting were included in the study. Levels of IgE and CRP were determined pre- and poststent implantation on four consecutive days and at the end of the first as well as third month. Levels of these two markers were gradually elevated on postprocedure days while reaching peak values on the second and third days for IgE (initial 278 +/- 335 IU/mL vs peak 350 +/- 489 IU/mL, P = 0.01) and CRP (initial 0.5 +/- 0 mg/dL vs peak 2.7 +/- 3 mg/dL, P = 0.002), respectively. High levels gradually returned to baseline values determined at the end of the first and even third months after stent implantation implying an acute inflammatory reaction. Stent implantation seems not to cause any persistent and ongoing inflammatory response in the long-term.

Acute coronary disease Athero-Inflammation: Therapeutic approach

Antithrombotic therapy is the cornerstone of the treatment of acute coronary syndromes, but there is now evidence which indicates that by blocking inflammation, thrombosis and thus, acute coronary events, could be lowered. The concept of athero-inflammation emerges as the meeting point of different morbidities; dyslipemia, diabetes, hypertension, obesity, immunity, infection, hyperhomocyteinemia, smoking, etc. usual named as risk factors. Thus, beside specific drugs, earliest treatment, in the stage of inflammation, using anti-inflammatory drugs, should be considered since in patients with increased risk of acute coronary process are likely to have many point of origen throughout the coronary arteries. There are a body of evidences for supporting the potential of anti-inflammatory therapy to the prevention of inflammation and atherosclerosis. COX-2 inhibition may decrease endothelial inflammation reducing monocytes infiltration improving vascular cells function, plaque stability and probably resulting in a decrease of coronary atherothrombotic events.Trials including large numbers of patients in prospective double-blind randomized studies worthwhile to confirm the efficacy of NSAID, mainly, COX-2 inhibitors, together with aspirin in the prevention of coronary events in patients with acute coronary disease.

[Late T-lymphocyte and monocyte activation in coronary restenosis. Evidence for a persistent inflammatory/immune mechanism?]

AIMS

This study was made to determine if restenosis after percutaneous coronary angioplasty is associated with acute or chronic inflammatory/immunologic activity, and explored possible relationships with latent infection.

PATIENTS AND METHOD

Forty-six consecutive patients underwent elective PTCA and 6 months of angiographic follow-up. Peripheral venous blood samples were obtained at baseline, 24-48 h, and 4-6 months post-intervention. Flow-cytometric methods were used to measure early and late circulating leukocyte activation status. Il-6 and TNF-alpha cytokines, and Il-2 soluble receptor concentrations were determined in all plasma samples. Chlamydia pneumoniae and Cytomegalovirus antibody assays were performed to detect infectious disease.

RESULTS

Angiographic coronary stenosis developed in 27 out of 46 patients. At 6 months of follow-up, these patients showed a significant increase in circulating cytotoxic T-lymphocytes CD3+/CD56+ (18.8 7.1 vs 6.12 2.7%; p = 0.005) and activated monocytes (CD11b: 1,383 624 vs 990 484 MFI, p = 0.025; CD64: 76.0 28.7 vs 56.7 21.8 MFI; p = 0.014), with no apparent relation to increased cytokines or latent infectious disease.

CONCLUSIONS

Restenosis appears to be associated to inflammatory and immunological activity that persists 6 months after coronary intervention. No relationship was found with the infections studied. The presence of inflammatory activity 4-6 months after PTCA suggess that pharmacological therapeutic interventions to prevent restenosis should be maintained for months.

Activation of circulating platelets in patients with peripheral arterial disease during digital subtraction angiography and percutaneous transluminal angioplasty

Platelet activation plays a crucial role in the pathogenesis of coronary heart disease (CHD), peripheral arterial disease (PAD) and cerebral ischaemia, the three main clinical manifestations of atherosclerosis. Circulating-activated platelets are thought to trigger ischaemic complications after angiography, angioplasty and vascular surgery. We studied activation of circulating thrombocytes in patients with PAD and evaluated the influence on platelet activation of intraarterial digital subtraction angiography (DSA) and percutaneous transluminal angioplasty (PTA) in the area of the lower extremities. Our study included 16 control subjects with PAD (clinical stage IIb according to Fontaine), 25 healthy control subjects and 34 PAD patients (clinical stage IIb according to Fontaine), 14 of whom we examined during DSA, 10 during PTA and 10 which we studied during both interventions. To characterize platelet ex vivo activation, the expression of activation-dependent platelet antigens (CD62 and CD63) was measured using flow cytometry. Platelet sensitization was analysed by an additional in vitro activation. Our results show that angioplasty in peripheral vessels causes activation and presumably slight migration or a reduction in the life span of circulating thrombocytes immediately after the PTA procedure and up to 4 h afterwards. DSA was also found to be associated with platelet activation, sensitization and presumptive minor migration or shortened life span of circulating platelets. Immediately after the intervention, PTA seems to influence platelet migration or shortened lifetime of platelets to a greater extent than DSA. We postulate that this is mainly induced by dilatation. More activated and sensitized thrombocytes circulated in patients with PAD compared to healthy control subjects. This supports our assumption that preactivated platelets are particularly involved in activation, sensitization and migration processes or affected by a reduced life span.

Immunosuppressive Therapy for the Prevention of Restenosis after Coronary Artery Stent Implantation (IMPRESS Study)

OBJECTIVES

This study tested the effect of oral prednisone on clinical and angiographic restenosis rate after successful stent implantation in patients with persistent elevation of systemic markers of inflammation after the procedure.

BACKGROUND

Experimental studies have shown that corticosteroids have the potential to reduce the inflammatory response associated with stent implantation.

METHODS

Eighty-three patients undergoing successful stenting with C-reactive protein (CRP) levels >0.5 mg/dl 72 h after the procedure were randomized to receive oral prednisone or placebo for 45 days. The primary clinical end point was 12-month event-free survival rate (defined as freedom from death, from myocardial infarction, and from recurrence of symptoms requiring additional revascularization). The angiographic end points were restenosis rate and late loss at six months.

RESULTS

Twelve-month event-free survival rates were 93% and 65% in patients treated with prednisone and placebo, respectively (relative risk [RR] 0.18, 95% confidence intervals [CI], 0.05 to 0.61, p = 0.0063). Six-month restenosis rate and late loss were lower in prednisone-treated than in placebo-treated patients (7% vs. 33%, p = 0.001, and 0.39 +/- 0.6 mm vs. 0.85 +/- 0.6 mm, p = 0.001, respectively).

CONCLUSIONS

In patients with persistently high CRP levels after successful coronary artery stent implantation, oral immunosuppressive therapy with prednisone results in a striking reduction of clinical events and angiographic restenosis rate.

The GP IIb/IIIa inhibitor abciximab (c7E3) inhibits the binding of various ligands to the leukocyte integrin Mac-1 (CD11b/CD18, alphaMbeta2)

Cross-reactivity with integrins other than glycoprotein IIb/IIIa (GP IIb/IIIa) is discussed as a potential reason for the overall clinical benefits of the GP IIb/IIIa-blocking antibody-fragment abciximab. We evaluated whether abciximab binds to the leukocyte integrin Mac-1, whether it inhibits binding of the distinct ligands and thereby may modulate inflammation, cell proliferation and coagulation. Binding of fluorescence-labelled abciximab to phorbolmyristate acetate-stimulated monocytes and to a monocytic cell line (THP-1) could be detected in flow cytometry. The binding of fibrinogen, the inactivated complement factor 3b (iC3b), and the coagulation factor X to Mac-1 could be inhibited by abciximab (10 microg/ml) in vitro. As a functional consequence, the conversion of factor X to factor Xa mediated by Mac-1, as detected by the chromogenic substrate SZ-2222, was impaired by abciximab. Adhesion of THP-1 cells to immobilized intercellular adhesion molecule 1 (ICAM-1) and to fibrinogen was reduced significantly by abciximab. Fibrinogen-mediated cell aggregation was also impaired. In conclusion, we describe binding of abciximab to Mac-1 on stimulated monocytes. Thereby, abciximab inhibits binding of the ligands fibrinogen, ICAM-1, iC3b and factor X. Furthermore, we demonstrated that Mac-1-dependent conversion from factor X to factor Xa is impaired by abciximab, arguing for the direct modulation of the coagulation cascade by abciximab. Overall, the inhibition of Mac-1 could provide additional clinical benefits of abciximab beyond the well-described blockade of GP IIb/IIIa.

Platelet and leukocyte activation during aortoiliac angiography and angioplasty

OBJECTIVE

to evaluate platelet and leukocyte activation during aortoiliac angiography and percutaneous transluminal angioplasty (PTA).

METHODS

an observational study of 14 patients with aortoiliac atherosclerotic disease, nine of whom underwent PTA. The proportion of fibrinogen-, and P-selectin positive platelets, P-selectin expression on platelets, intraplatelet cGMP and cAMP, CD18 positive granulocytes, CD18 expression on granulocytes, plasma (p)-neopterin, p-TNF alpha and p- interleukin-6 were repeatedly measured in arterial blood during angiography and in venous blood before and after.

RESULTS

compared to a previous venous sample, arterial intraplatelet cAMP was increased proximal to the atherosclerotic lesion before contrast infusion and PTA (median 18 [range: 14-22] vs 16 [15-21] pmol/10(9) platelets p<0.05), and intraplatelet cGMP was increased proximal to the lesion after contrast infusion and PTA (1.2 [0.8-3.9] vs 0.9 [0.6-2.5] pmol/10(9) platelets p<0.05). Four hours after angiography, both the proportion of P-selectin positive platelets (28[11-55]%) and platelet P-selectin expression (9[6-40]) had decreased (p<0.05), from arterial values distal to the lesion before contrast infusion and PTA (57 [24-78]% and 26 [10-83]). Granulocyte CD18 expression was lower during angiography than in a previous venous sample.

CONCLUSIONS

the results are compatible with platelet but not leukocyte activation during peripheral angiography.

Local blood serotonin and soluble P-selectin levels during percutaneous transluminal balloon angioplasty and primary stenting of the iliac artery

BACKGROUND

The activation of platelets or leukocytes plays an important role in development of intimal hyperplasia. We investigated whether the local blood serotonin and soluble P-selectin levels changed during endovascular therapy of the iliac artery.

METHODS

Blood samples were obtained from the iliac artery of 18 lower limbs undergoing percutaneous balloon angioplasty alone (8 limbs, group I) or percutaneous balloon angioplasty and primary stenting (10 limbs, group II). The serotonin levels in platelet-poor plasma were measured in all limbs. In group I the urinary level of the serotonin metabolite 5-hydroxyindoleacetic acid was also measured 24 hours before and 24 hours after the procedures. The soluble P-selectin levels were measured in the 6 patients in group II.

RESULTS

Before angioplasty the mean (+/- SEM) serotonin concentrations were 1.2 +/- 0.2, 1.2 +/- 0.4, and 1.2 +/- 0.3 ng/mL in all cases, group I, and group II, respectively. After angioplasty these values changed to 1.7 +/- 0.4 (P =.0750), 1.2 +/- 0.4 (P =.8001), and 2.1 +/- 0.6 ng/mL (P =.0529), respectively. In group I urinary 5-hydroxyindoleacetic acid concentrations 24 hours before and 24 hours after the procedures were 0.0026 +/- 0.0004 and 0.0031 +/- 0.0006 mg/mg creatinine, respectively (P =.2566). In group II the soluble P-selectin levels significantly increased after intervention, from 26.0 +/- 5.7 to 33.9 +/- 5.3 ng/mL (P =.0296).

CONCLUSIONS

Although the serotonin levels did not change significantly, the soluble P-selectin levels increased significantly after intervention. Leukocyte activation may therefore contribute to the progression of restenosis after peripheral endovascular therapy.

Inflammation as a key event in the development of neointima following vascular balloon injury

1. The present review discusses the current evidence to implicate leucocytes as key players in the development of neointima in arteries that have been subjected to balloon angioplasty injury. 2. There is substantial clinical evidence that leucocytes are activated after angioplasty, as determined by increased plasma levels of both leucocyte granulation products and soluble leucocyte and endothelial cell adhesion molecules. 3. Experimental evidence to implicate leucocytes in neointimal formation comes from studies that demonstrate leucocyte accumulation occurs within the vascular wall soon after injury and that induction of leukopenia prevents neointimal formation. 4. The evidence implicating specific adhesion molecules and cytokines in the key events leading to neointimal formation is discussed.

Leukocyte/endothelium activation and interactions during femoral percutaneous transluminal angioplasty

Recent data suggest that leukocyte-endothelium activation/interactions are important for restenosis after percutaneous transluminal angioplasty (PTA). Ten patients with superficial femoral artery occlusive disease (stage Fontaine IIb) were examined after a percutaneous transluminal angioplasty (PTA) versus a preceding aortoangiography (AAG). Blood samples from corresponding femoral arteries and veins were obtained before, immediately after, and 4 hours after each procedure. The authors examined the ex vivo respiratory burst and leukocytic expression of adhesion molecules flowcytometrically, adhesion molecule plasma concentrations, and inflammatory mediators concentrations in plasma and in endotoxin-stimulated whole blood cultures by ELISA, and the leukocyte counts. After PTA, venous plasma concentrations of soluble (s)L-selectin (148.2 +/-14.7%, p<0.05 vs 100% baseline +/- sem), sP-selectin (130.7 +/-6.9%, p<0.01; sE-selectin (117.5 +/-8.3%, p<0.05 vs arterial), sLFA-3 (130.7 +/-15.8%, p<0.05) were increased. Expressions of L-selectin (93.0 +/-5.7%, p<0.05 vs arterial), CD11a (98.8 +/-3.8%, p=0.06), CD18 (96.9 +/-4.0%, p<0.05 vs arterial), and ICAM-1 (89.1 +/-7.7%, p<0.05) on polymorphonuclear neutrophils (PMN), and arteriovenous leukocyte counts (arterial: 103.5 +/-5.4%, venous: 91.1 +/-3.3%, p<0.05) decreased. Venous ex vivo secretions of oxygen radicals (141.4 +/-28.1%, p<0.05 vs AAG), PMN-elastase (173.7 +/-35.7%, p<0.05 vs AAG), and interleukin (IL)-8 (226.5 +/-56.4%, p<0.001; p<0.0001 vs AAG), as well as PMN-elastase (173.7 +/-35.7%, p<0.05 vs AAG) and tumor necrosis factor (TNF)-alpha plasma concentrations (124.1 +/-11.9%, p=0.06) rose. Four hours after PTA, a leukocytosis and exhausted TNF-alpha (69.8 +/-10.4%, p<0.05) and IL-8 secretions (72.4 +/-4.6%, p<0.01) occurred. PTA induced local leukocyte-endothelium activations (stronger ex vivo mediator productions) and interactions (decreased venous leukocyte counts, increased plasma concentrations, and decreased leukocytic expression of adhesion molecules) with the release of inflammatory mediators (higher plasma concentrations and exhaustions after 4 hours).

Comparison of activation process of platelets and neutrophils after coronary stent implantation versus balloon angioplasty for stable angina pectoris

The pathophysiologic features of stent-induced cellular responses of platelets and leukocytes have not been established. This study was designed to clinically investigate the activation of platelets and neutrophils after coronary stenting and to identify its effects on the long-term results of coronary stents. Forty-eight consecutive patients with left anterior descending coronary artery disease indicating coronary intervention were randomly assigned to either a balloon angioplasty group or a coronary stent group. Flow cytometric analysis demonstrated that the transcardiac gradient (the value of coronary sinus blood minus the value of peripheral blood) of platelet surface expression of CD62P (p < 0.001) and CD63 (p < 0.01) increased immediately after coronary stenting, but increased less significantly immediately after balloon angioplasty (CD62P, p < 0.01; CD63, p < 0.05). These increases were persistently observed after coronary stenting but transiently after balloon angioplasty alone during a 48-hour observation period after the procedures. The gradient for neutrophil surface expression of CD11b increased, and that of CD62 L decreased 48 hours after coronary stenting (CD11b, p < 0.001; CD62 L, p < 0.05), but these changes showed less significance 48 hours after balloon angioplasty alone (CD11b, p < 0.05; CD62 L, p = NS). The gradients 48 hours after the procedures for both CD62P (r = 0.39, p < 0.05) and CD11b (r = 0.44, p < 0.01) were independently correlated with the late loss in the stent group, whereas the correlation was seen only for CD11b (r = 0.38, p < 0.05) in the balloon angioplasty group. Both platelet and neutrophil activation was greater after coronary stenting than after balloon angioplasty. Cellular interactions between platelets and neutrophils may be related to the progression of neointimal proliferation leading to restenosis after coronary stent implantation.

Correlation of leukocyte adhesiveness, adhesion molecule expression and leukocyte-induced contraction following balloon angioplasty

1. The aim of this study was to examine the changes in leukocyte adhesion and leukocyte-induced contraction in balloon-injured rabbit subclavian artery and to correlate these changes with vessel morphology and expression of adhesion molecules on the injured arteries. 2. Rabbits were anaesthetized and their left subclavian arteries were injured by balloon inflation and withdrawal followed by sacrifice at 2, 24, 48 h or 8 days after injury. The left and right subclavian arteries were removed and leukocytes were isolated from autologous rabbit blood. Leukocyte-induced contraction was measured in 5-HT precontracted artery rings and leukocyte adhesion was measured using (51)Cr-labelled leukocytes. Immunocytochemistry using paraffin-embedded tissue was employed to detect changes in the expression of adhesion molecules on injured arteries. 3. Autologous leukocytes caused a contraction of rabbit subclavian artery rings, which was prevented by L-NAME (10(-3) M). Balloon-induced injury abolished the contractile response to leukocytes, which correlated with loss of carbachol-induced relaxation 4. Balloon injury markedly enhanced the adhesiveness of the subclavian artery for leukocytes, most notably at 24 and 48 h after injury (1.7 and 1.8 fold respectively). Increased leukocyte adhesion at these two time points correlated with an upregulation of E-selectin, P-selectin and VCAM-1 expression on the remaining endothelium of the injured artery. 5. Vessel morphology revealed that balloon inflation had induced an infiltration of inflammatory cells into the vessel wall, the greatest increase being seen at 24 h after injury. 6. It is concluded that an increase in the expression of E-selectin, P-selectin and VCAM-1 following balloon-induced injury leads to enhanced leukocyte adhesion and migration into the injured vessel.

Enhanced inflammatory response in patients with preinfarction unstable angina

OBJECTIVES

We assessed the extent and the time course of the acute phase response following myocardial cell necrosis and its relationship with the presence of preinfarction unstable angina (UA).

BACKGROUND

Elevated levels of acute phase proteins have been reported in patients with UA and in patients with acute myocardial infarction (MI).

METHODS

C-Reactive Protein (CRP), serum amyloid A protein (SAA) and interleukin-6 (IL-6) were measured in 36 patients with MI admitted within 3 h from symptoms onset. All patients had normal levels of creatine kinase and of troponin T on admission, rising above diagnostic levels within 6 to 12 h. Blood samples for CRP, SAA and IL-6 measurements were taken on admission, at 6, 24, 48, 72 h and at discharge.

RESULTS

Twenty of the 36 patients studied presented an unheralded MI (Group 1); the remaining 16 patients had symptoms of unstable angina in the preceding 7 days (Group 2). Group 2 patients have much higher levels of CRP and SAA on admission (median values 8.8 vs. 3 mg/L and 28 vs. 3.4 mg/L, respectively, all p<0.001). Following the necrotic insult, despite similar infarct size and clinical signs of reperfusion, Group 2 patients had strikingly higher peaks of IL-6 (median values 85.2 vs. 19 pg/ml, p<0.05), CRP (50 vs. 31.4 mg/L, p<0.05) and SAA (228 vs. 45 mg/L, p<0.001).

CONCLUSIONS

Our data demonstrated that the acute phase response is greatly enhanced in patients with preinfarction UA compared with those presenting with an unheralded MI. The significant differences in acute phase response observed in these two clinical presentations of MI indicate a major difference in their underlying pathogenetic components.

Peripheral blood mononuclear cell production of interleukin-8 and IL-8-dependent neutrophil function in hypercholesterolemic patients

Interleukin-8 is a cytokine produced by mononuclear cells that is involved in polymorphonuclear neutrophil leukocyte (PMN) recruitment and activation. Several studies have previously demonstrated a leukocyte activation during hypercholesterolemia and 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors have been found to play a role in the prevention of atherothrombotic disease. The purpose of this study was to determine interleukin-8 (IL-8) mRNA expression and ex vivo production from peripheral blood mononuclear cells (PBMCs) and IL-8-dependent PMN activation of hypercholesterolemic (HC) patients with respect to normocholesterolemic (NC) subjects. Using Northern blot analysis, we found a four- and threefold increase in the amount of IL-8 transcript in PBMC from HC patients, in unstimulated and LPS stimulated cultures, respectively. A specific immunoassay showed a correspondingly significant increase of IL-8 immunoactivity in the conditioned medium of PBMC from HC subjects as compared with controls (unstimulated PBMC: 15 +/- 4 vs. 4.2 +/- 3 ng/ml; P < 0.0001; LPS stimulated PBMC: 65.3 +/- 8 vs. 36.6 +/- 9 ng/ml; P < 0.0001). PMN of HC patients stimulated with IL-8 showed a reduced elastase release with respect to NC subjects before physiological granule release after f-Met-Leu-Phe (fMLP) treatment. These results indicate an upregulation of the IL-8 system in dyslipidemic patients and provide evidence for ongoing in vivo IL-8-dependent PMN activation during hypercholesterolemia.

Priming of superoxide anion in polymorphonuclear neutrophils by brain natriuretic peptide

In acute coronary syndromes such as unstable angina and myocardial infarction, serum concentration of brain natriuretic peptide, a cardiac hormone with potent vasodilatatory, natriuretic and diuretic activities, is elevated. Little is known about the effect of elevated BNP plasma concentration on free radical-mediated tissue damage in these states. We investigated the influence of human BNP 32 and its fragment BNP 7-32 on the production of superoxide anion by PMN, a major cause for myocardial damage. Although BNP showed itself no stimulatory potential on superoxide anion release in PMN, it enhanced significantly the stimulatory potential of cell stimuli such as fMLP or phorbol 12-myristate 13-acetate (PMA) in PMN. Thus our data show that the cardiac-derived hormone BNP influences an important function of PMN. This 'priming' effect of BNP on PMN may contribute to the tissue damage occuring during acute coronary syndromes.

Pentoxifylline decreases neutrophil respiratory bursts in patients with stable angina

We estimated the effect of pentoxifylline (PTX) on the respiratory burst (examined by chemiluminescence method) of unprimed and primed neutrophils with tumor necrosis factor-alpha (TNF-alpha) in patients with stable angina pectoris. Chemiluminescence of non-stimulated as well as formyl-methionyl-leucyl-phenylalanine (fMLP) and phorbol myristate acetate (PMA) stimulated neutrophils was measured. We studied 45 patients with stable angina subjected to percutaneous transluminal coronary angioplasty (PTCA) procedure, who were randomly divided into two groups. The study group consisted of 24 patients who were administered pentoxifylline orally, and the control group consisted of 21 patients without pentoxifylline administration. Blood samples for examination were collected from the coronary sinus and peripheral vein just before the PTCA procedure. Pentoxifylline decreased the respiratory burst of non-stimulated and fMLP-stimulated neutrophils without affecting the chemiluminescence of PMA stimulated neutrophils. Moreover, pentoxifylline diminished the chemiluminescence non-stimulated and stimulated by fMLP but not by PMA of TNF-alpha primed neutrophils. We presume that administration of PTX in stable angina patients may have a beneficial effect.

Chimeric 7E3 Fab (ReoPro) decreases detectable CD11b on neutrophils from patients undergoing coronary angioplasty

OBJECTIVES

The purpose of this study was to monitor the effects of chimeric 7E3 Fab (ReoPro) on leukocyte and platelet activation and interaction during coronary angioplasty.

BACKGROUND

Increased expression of CD11b on monocytes and neutrophils promotes their adhesion to endothelial cells, extracellular matrix and smooth muscle cells. Thrombin-activated platelets adhere via P-selectin to monocytes and neutrophils. These cell interactions may affect the outcome of coronary angioplasty.

METHODS

During coronary angioplasty, venous blood was obtained for flow cytometric detection of leukocyte CD11b; platelet CD41a, CD61a and CD62P; the percentage of leukocytes with adherent platelets and the intensity of bound platelet fluorescence.

RESULTS

Leukocyte CD11b expression increased after angioplasty in control patients (neutrophils 171+/-25 to 255+/-31 mean fluorescence intensity [MFI, mean+/-SEM], n=25, p < 0.0001; monocytes 200+/-40 to 248+/-36 MFI, n=17, p < 0.05) and decreased in the patients selected to receive chimeric 7E3 Fab (neutrophils 146+/-30 to 82+/-22 MFI, n=25, p < 0.0001; monocytes 256+/- 53 to 160+/-38 MFI, n= 17, p < 0.05). Neutrophil CD11b decreased after in vitro incubation of whole blood with chimeric 7E3 Fab (n=5, p=0.01), but fMLP-induced increases in CD11b were not prevented. The CD11b expression was unchanged and increased with fMLP stimulation after in vitro incubation of isolated neutrophils with chimeric 7E3 Fab. Direct-labeled chimeric 7E3 Fab was not detected bound to neutrophils in whole blood or isolated cells using flow cytometric techniques. Adhesion of isolated neutrophils to protein-coated glass was not prevented by in vitro incubation with chimeric 7E3 Fab. Platelet activation increased after angioplasty in control patients (CD62P 8.9+/-0.8 to 12.3+/-1.2 MFI, n=25, p < 0.05; CD41a 382+/-25 to 454+/-26 MFI, n=25, p < 0.05, CD61a 436+/-52 to 529+/-58 MFI, n=11, p < 0.05); it did not increase in the patients selected to receive chimeric 7E3 Fab (CD62P 13.2+/-1.0 to 9.0+/-0.9 MFI, n=25, p < 0.05; CD61a 398+/-32 to 410+/-38 MFI, n=7, p=NS). Leukocytes with adherent platelets tended to increase in the control group of patients and decrease after the procedure in patients selected to receive chimeric 7E3 Fab; individual and procedure-related variability were marked.

CONCLUSIONS

Despite standard aspirin and heparin therapy, leukocyte and platelet activation with platelet adherence to leukocytes occurs after coronary angioplasty. Although chimeric 7E3 Fab does not bind to leukocytes directly, it influences CD11b expression in whole blood. Modulation of platelet and leukocyte activation and interaction by chimeric 7E3 Fab may contribute to an improved outcome after coronary angioplasty.

Predictive value of C-reactive protein after successful coronary-artery stenting in patients with stable angina

Plasma levels of C-reactive protein were measured 72 hours after successful coronary artery stenting in 76 patients with stable angina pectoris. At 12-month follow-up, the cumulative event rate was higher in patients with abnormal levels of C-reactive protein than that observed in patients with normal C-reactive protein who were event free.

Acute myocardial infarction and increased soluble intercellular adhesion molecule-1: a marker of vascular inflammation and a risk of early restenosis?

BACKGROUND

Plasma levels of soluble intercellular adhesion molecule-1 (sICAM-1) have been shown to predict activities of inflammatory disorders and malignancies. However, it is unknown whether the plasma level of sICAM-1 is increased in patients with acute myocardial infarction (AMI) with coronary intervention and whether the levels have any diagnostic or predictive values for vascular disease activity in patients with AMI.

METHODS

We prospectively observed the time course of the plasma sICAM-1 levels in 20 patients with AMI whose infarct-related coronary artery was successfully recanalized by emergency balloon angioplasty. sICAM-1 was measured by enzyme-linked immunoassay.

RESULTS

At admission, 48 hours, 1 week, and 2 weeks after angioplasty, sICAM-1 levels were significantly elevated in patients who had early (3 weeks) restenosis develop compared with those who did not (p < 0.05). At the other time points examined, there was a tendency of higher sICAM-1 levels in patients with than without restenosis (0.06 < p < 0.09). The relation of sICAM-1 levels and total white blood cell counts, neutrophil counts, or numbers of diseased major coronary artery branches was not statistically significant.

CONCLUSIONS

A persistent increase in plasma sICAM-1 levels may indirectly implicate vascular inflammation, which could predict the risk of early coronary restenosis after emergency angioplasty in patients with AMI. Hence, measurements of sICAM-1 in patients with AMI would serve as a potentially useful predictor of the risk of early postangioplasty restenosis.

Interactive role of infection, inflammation and traditional risk factors in atherosclerosis and coronary artery disease

Although first suggested at the turn of the 20th century, there is a renewed interest in the infectious theory of atherosclerosis. Studies done in many laboratories around the world over the past several years have shown an association between markers of inflammation and coronary atherosclerosis with an exacerbation of the inflammatory process during acute myocardial ischemia, particularly in the early stages of reperfusion. It is also being recognized that the traditional risk factors, such as smoking, dyslipidemia, hypertension and diabetes mellitus, do not explain the presence of coronary atherosclerosis in a large proportion of patients. We believe that in certain genetically susceptible people, infection with very common organisms, such as Chlamydia pneumoniae or cytomegalovirus, may lead to a localized infection and a chronic inflammatory reaction. Persistence of infection may relate to the degree of inflammation and severity of atherosclerosis. Early trials with appropriate antibiotic agents in some patients with a recent history of acute myocardial infarction have led to very salutary results. If patients with an infectious basis of atherosclerosis can be identified, a therapy directed at eradication of the offending organism may be appropriate.

Platelets, neutrophils, and vasoconstriction after arterial injury by angioplasty in pigs: effects of MK-886, a leukotriene biosynthesis inhibitor

1 Leukotrienes constitute a class of potent bioactive mediators known to play a pivotal role in inflammation. Since their biosynthesis has been shown to be enhanced by platelet-neutrophil interactions, leukotrienes may be involved in these interactions and the arterial response to injury. Therefore, we investigated the effects of the selective leukotriene biosynthesis inhibitor 3-[1-(4-chlorobenzyl)-3-t-butyl-thio-5-isopropylindol-2-yl]-2,2- dimethylpropanoic acid (MK-886) on the acute thrombotic and vasomotor responses after arterial injury by angioplasty. 2 Carotid arterial injury was produced by balloon dilatation in control (molecusol vehicle; n=10) and treated (MK-886, 10 mg kg(-1), i.v.; n=9) pigs. The acute thrombotic reaction following deep arterial wall injury was quantified with 51Cr labelled platelets and 111In labelled neutrophils, and the vasomotor response was determined angiographically. 3 Platelet deposition at the site of deep arterial wall injury averaged 56.4+/-11.0x10(6) platelets cm(-2) in the control group, and was significantly reduced to 18.2+/-3.8x10(6) platelets cm(-2) (P<0.005) by treatment with MK-886. Neutrophil deposition was also decreased by MK-886, from 242.8+/-36.8 to 120.9+/-20.3x10(3) neutrophils cm(-2) (P<0.01). MK-886-treated animals had a significant decrease in the postangioplasty vasoconstrictive response at the site of endothelial injury distally, from 37.5+/-3.1% in the control group to 13.5+/-2.5% (P<0.001). 4 The effects of MK-886 were associated with a profound inhibition of ex vivo leukotriene B4 (LTB4) synthesis in blood stimulated by the calcium ionophore A23187 and a significant reduction of neutrophil aggregation in whole blood (P<0.01), whereas neutrophil superoxide anion production, serum thromboxane B2 and platelet aggregation in whole blood were not influenced. 5 The relevant effects of MK-886 are primarily related to inhibition of neutrophil function and suggest an important modulatory role for leukotrienes in the pathophysiological response associated with platelet and neutrophil interactions following arterial injury in vivo.

Neutrophil-derived oxidative stress after myocardial ischemia induced by incremental atrial pacing

We studied the effect of atrial pacing-induced myocardial ischemia on the generation of oxygen free radicals (OFR) in 8 patients with verified coronary artery disease (CAD) and in a control group of 4 patients without coronary atherosclerosis. Myocardial ischemia was measured metabolically by simultaneous lactate sampling from coronary sinus (CS) and arterial blood. Generation of OFR from purified viable polymorphonuclear neutrophils (PMN) was assessed by means of the chemiluminescence (CL) method. At peak pacing, 7 of 8 patients with CAD exhibited transient myocardial ischemia (mean lactate extraction ratio at rest: 23.6 +/- 7.7 vs 5.21 +/- 5.1% at peak pacing, p = 0.012). In these patients, unstimulated PMN harvested from the CS depicted a significant increase of luminol-enhanced CL (from 1.06 +/- 0.54 to 2.15 +/- 1.28 cpm x 10(5), p = 0.012) after atrial pacing. There was no additional effect from further ex vivo stimulation with phorbol myristate acetate. This finding underscores the role of myocardial ischemia as a potent endogenous activator of PMN function and may have implications in the pathogenesis and progression of atherosclerosis.

Host tissue damage by phagocytes

Evidence continues to accumulate on the importance of neutrophils (PMNs) and phagocytes in the causation of tissue and endothelial injury that frequently accompanies the inflammatory response. Increased production of superoxide anions in combination with decreased endothelial antioxidant activity may contribute to the development of vascular disease including atherosclerosis, vasospasm, diabetic vascular complications, tissue damage in ischemia-reperfusion, and hypotension. Free radicals generated in the vascular wall may act directly on smooth muscle or interact with each other thus producing biologically active endogenous mediators. Derangement of macrophage function may occur in conditions characterized by protein malnutrition, thus leading to failure to develop a specific immunoresponse and to an increase in the production of oxygen intermediate radicals, which may cause tissue damage. A local inflammatory response followed by endothelial cell activation could also facilitate migration of immunocompetent cells into the parenchyma of grafted organs and stimulate dendritic cells in the graft. There is now convincing evidence that excessive and prolonged production of NO contributes to tissue damage in septicemia, ischemia/reperfusion injury, and other inflammatory conditions. There is also increasing evidence that the complement system plays an important role in tissue damage in association with phagocytes, e.g., in ischemia/reperfusion injury, carcinogenesis, and aging. It can therefore be surmised that phagocytic cells may act both as "friends" and as "foes" and that they are important mediators of tissue damage in a variety of conditions.

Effects of coronary angioplasty on monocyte tissue factor response in patients with stable or unstable angina

Balloon coronary angioplasty is a revascularization procedure which increases the luminal diameter at a site of arterial stenosis, leading to mechanical disruption of the atherosclerotic plaque and to stretching of the vascular wall (1). This procedure can be complicated by thrombosis or restenosis, which occur in 5% and 30% of the cases respectively (2). These complications probably result from exposure of blood to components of atherosclerotic plaque, subendothelium and components of vascular wall, leading to activation of coagulation (thrombin generation) and platelets (3,4). Recent data point to simultaneous increase of leukocyte adhesive receptors, indicating an additional process of leukocyte activation, which could play a key role in the vascular healing process after angioplasty (5). These elements could also play a role in the thrombotic and stenotic complications.

Priming of neutrophils after elective percutaneous transluminal coronary angioplasty is unrelated to accompanying brief myocardial ischemia

OBJECTIVE

The purpose of this study was to investigate the effect of brief myocardial ischemia and vascular trauma induced by elective percutaneous transluminal coronary angioplasty on in vivo 'priming' and activation of neutrophils.

PATIENTS AND METHODS

We studied 16 patients undergoing elective coronary angioplasty for symptomatic coronary artery disease and a control group of seven patients undergoing diagnostic cardiac catheterization. Free radical production from purified neutrophils (Ficoll-Hypaque density gradient method) was measured indirectly by the chemiluminescence method. Myocardial ischemia during balloon inflation was assessed by serial lactate determinations from coronary sinus and arterial blood. The degree of transient angioplasty-related myocardial ischemia was related to the oxidative response of activated neutrophils.

RESULTS

Mean (+/-S.E.M.) oxidative response, i.e. the lucigenin- and luminol-enhanced-chemiluminescence (counts per minute) of neutrophils sampled from the coronary sinus increased significantly after percutaneous transluminal coronary angioplasty (Lucigenin-chemiluminescence: pre-angioplasty 3.69+/-0.64x10(5) vs. post-angioplasty 7.08+/-1.2x10(5), P<0.01; Luminol-chemiluminescence: pre-angioplasty 2.81+/-0.67x10(6) vs. post-angioplasty 5.2+/-0.92x10(6), P<0.01). Twelve of 16 patients developed transient cardiac lactate production (mean coronary sinus lactate excess: +0.12 mmol/l) and three disclosed a lactate extraction ratio <10%, both suggestive of myocardial ischemia. However, there was no correlation between the cardiac lactate production and the increased oxidative response after coronary angioplasty (r2 (Lucigenin-chemiluminescence)=0.02, n.s.; r2 (Luminol-chemiluminescence)=0.06, n.s.).

CONCLUSION

'Priming' of neutrophils, as reflected by increased oxidative response, is likely to occur after coronary angioplasty, but not after the angiographic procedure itself. However, 'priming' seems to be unrelated to the transient brief period of myocardial ischemia and rather depends on an alternative mechanism.

Membrane phosphorylation protects the cardiac sarcoplasmic reticulum Ca(2+)-ATPase against chlorinated oxidants in vitro

OBJECTIVE

The calcium (Ca) pump of cardiac sarcoplasmic reticulum (SR) membranes is vulnerable to oxidation and hence likely to be damaged by chlorinated compounds, specifically hypochlorite (NaOCl) and monochloramine (NH2Cl), the most potent oxidants produced upon neutrophil activation. This could occur during prolonged ischemia or myocardial infarction when tissue levels of catecholamines are high. Phospholamban (PLN), the phosphorylatable regulator of the Ca pump, plays a central role in the effects of beta-adrenergic agonists on the heart. The purpose of this study was to investigate a possible role of PLN in determining the pump's sensitivity to NaOCl and NH2Cl.

METHODS

Ca-uptake and Ca(2+)-ATPase activities in purified phosphorylated and control canine cardiac microsomes, incubated at increasing concentrations of NaOCl or NH2Cl, were related to the extent of PLN phosphorylation by protein kinase A, which was quantitated by PhosphorImager analysis.

RESULTS AND CONCLUSIONS

Our data indicate that microsomal phosphorylation protects the Ca pump fully against 10 microM NaOCl or NH2Cl, which inhibit Ca-uptake by 21-41% when assayed at 25 or 37 degrees C and saturating Ca2+ in unphosphorylated microsomes, and protects partially at higher oxidant concentrations. The protective effect of protein kinase A on Ca-uptake is proportional to the amount of phosphorylated PLN. No comparable protection against similar oxidative damage of the Ca pump is observed when light fast skeletal muscle microsomes, which lack PLN, are incubated under conditions favorable for phosphorylation nor when PLN's inhibition of the cardiac Ca pump is relieved by proteolytic cleavage of its cytoplasmic domain. Our findings contribute toward an understanding of possible endogenous protective mechanisms that may promote calcium homeostasis in myocardial cells in inflammatory states associated with neutrophil activation and may suggest an approach toward development of protective strategies against oxidative damage in the heart.

Coronary angioplasty results in leukocyte and platelet activation with adhesion molecule expression. Evidence of inflammatory responses in coronary angioplasty

OBJECTIVES

This study sought to characterize leukocyte and platelet activation and adhesion molecule expression after coronary angioplasty.

BACKGROUND

Coronary angioplasty can be regarded as a clinical model of postischemic inflammation because this intervention leads to the release of inflammatory mediators as a result of plaque rupture and endothelial injury.

METHODS

In 13 patients with stable angina (mean [ +/- SEM] age 56.0 +/- 2.4 years, range 44 to 79), blood samples were drawn from the aorta and coronary sinus immediately before and immediately and 15 min after coronary angioplasty. Subsequently, leukocyte and platelet functions were determined. Eleven control patients (57.5 +/- 2.3 years, range 52 to 78) underwent coronary arteriography.

RESULTS

Coronary arteriography and angioplasty showed no difference in number of leukocytes between the coronary sinus and the aorta. However, 15 min after coronary angioplasty, there was an increase in neutrophil CD18 and CD11b, monocyte CD14 and platelet glycoprotein IIb/IIIa expression and a decrease in neutrophil L-selectin expression (189 +/- 25%, 163 +/- 27%, 158 +/- 35%, 141 +/- 22% and 31 +/- 10%, respectively, p < 0.01). In the control subjects, no change in adhesion molecule expression occurred. Superoxide production and aggregation in ex vivo-stimulated neutrophils collected from the coronary sinus 15 min after coronary angioplasty was significantly decreased compared with that after coronary arteriography (54 +/- 12% vs. 106 +/- 30% and 58 +/- 11% vs. 102 +/- 29%, respectively, p < 0.01). The reduced responses to phorbol ester stimulation may be explained by previous in vivo activation of neutrophils during coronary angioplasty.

CONCLUSIONS

Coronary angioplasty increases neutrophil, monocyte and platelet adhesion molecule expression and induces a significant decrease in ex vivo-stimulated neutrophil superoxide generation and aggregation. These findings suggest that coronary angioplasty triggers cellular activation with an inflammatory response that could contribute to restenosis.

Expression of polymorphonuclear leukocyte adhesion molecules and its clinical significance in patients treated with percutaneous transluminal coronary angioplasty

OBJECTIVES

This study evaluated the role of neutrophil adhesion molecules LFA-1 (CD11a/CD18), Mac-1 (CD11b/CD18) and p150,95 (CD11c/CD18) in patients undergoing percutaneous transluminal coronary angioplasty (PTCA).

BACKGROUND

Several recent studies have suggested that cell adhesion molecules on both neutrophils and vascular endothelial cells play an important role in the process of tissue inflammation.

METHODS

Thirty-eight patients (30 men, 8 women; mean [+/-SE] age 56 +/- 5 years, range 38 to 76) with single-vessel coronary artery disease of the left anterior descending artery underwent coronary angioplasty. Peripheral blood was sampled at baseline before, immediately after and 12, 24, 48 and 144 h after PTCA. The expression of CD18, CD11a, CD11b and CD11c on the surface of polymorphonuclear leukocytes was examined by flow cytometry with monoclonal antibodies.

RESULTS

In patients without subsequent restenosis, there was no change in mean channel fluorescence intensity (MFI) of CD18 at each sampling time. However, in the patients with restenosis, the MFI of CD18 significantly increased at 48 h after PTCA (from 57 +/- 6 to 73 +/- 8, p = 0.0008). The MFI of CD11b increased slightly at 48 h after PTCA in patients without restenosis (from 584 +/- 121 to 735 +/- 114, p = 0.037). In patients with restenosis, the MFI of CD11b was slightly increased at 24 h after PTCA (from 586 +/- 122 to 768 +/- 214, p = 0.018) and significantly increased at 48 h after PTCA (to 1,534 +/- 268, p = 0.0006). The expression of CD11a and CD11c did not change at any sampling points after PTCA in either of the two patient groups. Percent change in the expression of CD18 at 48 h after PTCA (from baseline) and that of CD11b were correlated (r = 0.73, p = 0.0008) in patients with restenosis.

CONCLUSIONS

Inflammatory stimuli within the coronary vessels associated with coronary angioplasty may upregulate Mac-1 expression on the surface of polymorphonuclear leukocytes. This process may be more marked in patients who experience later restenosis. Thus, activation of neutrophil adhesion molecule Mac-1 at 48 h after PTCA may have value as a predictor of subsequent restenosis.