Chemokine expression in coronary circulation after coronary angioplasty as a prognostic factor for restenosis

Circulating intermediate monocytes CD14++CD16+ are increased after elective percutaneous coronary intervention

AIM

Inflammation plays a central role in the pathogenesis of atherosclerosis and in the sequelae of percutaneous coronary intervention (PCI). Previous work demonstrated that intermediate monocytes (CD14++CD16+) are associated with adverse cardiovascular events, yet monocyte subset response following elective PCI has not been described. This article explores the changes in monocyte subset and humoral response after elective PCI.

METHODS

This prospective study included 30 patients without inflammatory diseases being referred for elective PCI. We included patients treated with drug coated balloons or 2nd generation drug eluting stents. Patients underwent blood tests at baseline (prior to PCI), four hours, two weeks and two months later. Analyses were performed in terms of monocyte subsets (classical CD14++CD16-, intermediate CD14++CD16+ and non-classical CD14+CD16++), gene expression of CD14+ leucocytes and humoral biomarkers.

RESULTS

Intermediate monocytes decreased significantly four hours after PCI, were recovered at two weeks, and increased significantly at two months post elective, uncomplicated PCI. They remain significantly elevated in the DES group but not in the DCB group. Gene expression analysis of CD14+ leucocytes showed IL18 had decreased expression at two weeks, CXCR4 and IL1β decreased at two months, while pentraxin 3 increased at two weeks and two months. In terms of humoral biomarkers, hsTnI remains elevated up to two weeks post PCI while IL6 and TNFα remain elevated till two months post PCI.

CONCLUSION

Intermediate monocytes increase significantly two months following elective, uncomplicated PCI. They remain significantly elevated in the DES group but not in the DCB group suggesting that the PCI strategy could be one of the ways to modulate the inflammatory response post PCI.

Inflammatory Cytokine Levels After Endovascular Therapy in Patients With Peripheral Artery Disease

We evaluated the impact of endovascular therapy (EVT) on inflammatory cytokine levels and its relationship with in-stent restenosis in patients with peripheral artery disease. The study prospectively enrolled 35 patients with intermittent claudication who underwent EVT of the iliofemoral artery. Levels of interleukin 6 (IL-6), monocyte chemoattractant protein-1 (MCP-1), and tumor necrosis factor α (TNF-α) were measured using enzyme-linked immunosorbent assay before and at 2 hours, 4 hours, and 3 months after EVT. All cytokine levels increased significantly after EVT (IL-6 [pg/mL]: from 1.51 [0.84-1.93] before EVT to 6.97 [4.05-20.41] at 2 hours and 13.29 [4.57-31.88] at 4 hours; MCP-1 [pg/mL]: from 326.65 [265.60-406.55] before EVT to 411.18 [341.21-566.27] at 2 hours and 519.36 [383.58-644.85] at 4 hours; TNF-α [pg/mL]: from 1.08 [0.77-1.29] before EVT to 1.25 [0.94-1.81] at 2 hours and 1.27 [0.95-1.59] at 4 hours, all P < .001). However, cytokine levels did not differ significantly between lesions with and without in-stent restenosis. Overall, our results suggest that EVT significantly increases IL-6, MCP-1, and TNF-α levels in the ischemic leg, but this effect is not associated with a higher rate of in-stent restenosis.

Nuclear PTEN functions as an essential regulator of SRF-dependent transcription to control smooth muscle differentiation

Vascular disease progression is associated with marked changes in vascular smooth muscle cell (SMC) phenotype and function. SMC contractile gene expression and, thus differentiation, is under direct transcriptional control by the transcription factor, serum response factor (SRF); however, the mechanisms dynamically regulating SMC phenotype are not fully defined. Here we report that the lipid and protein phosphatase, PTEN, has a novel role in the nucleus by functioning as an indispensible regulator with SRF to maintain the differentiated SM phenotype. PTEN interacts with the N-terminal domain of SRF and PTEN–SRF interaction promotes SRF binding to essential promoter elements in SM-specific genes. Factors inducing phenotypic switching promote loss of nuclear PTEN through nucleo-cytoplasmic translocation resulting in reduced myogenically active SRF, but enhanced SRF activity on target genes involved in proliferation. Overall decreased expression of PTEN was observed in intimal SMCs of human atherosclerotic lesions underlying the potential clinical importance of these findings.

The transcription factor, serum response factor, SRF regulates critical smooth muscle (SM) contractile gene expression but what else controls SM differentiation is unclear. Here, Horita et al. demonstrate that nuclear PTEN acts with SRF at the transcriptional level to maintain the differentiated SM phenotype.

Risk evaluation for coronary artery disease in patients with impaired glucose tolerance after a successful coronary intervention

PURPOSE

Patients with coronary artery disease (CAD) often have risk factors that may influence endothelial function. The purpose of this study was to evaluate the endothelial function and its association with coronary risk factors after percutaneous coronary intervention (PCI).

MATERIALS AND METHODS

A total of 14 patients with impaired glucose tolerance and CAD underwent positron emission tomography with N-13 ammonia to measure myocardial blood flow (MBF) at rest and during a cold pressor test (CPT), to estimate endothelial function as a percent increase (%increase) of MBF. The results were compared among normal segments (normal), reperfused segments with PCI (PCI), and nonculprit CAD segments without PCI (non-PCI). Correlations between the %increase and major risk factors were also investigated.

RESULTS

CPT induced significant increase in MBF in all groups. The %increase of normal, non-PCI, and PCI groups were 33% ± 22%, 21% ± 23%, and 26% ± 23%, respectively. Comparison with risk factors demonstrated significant correlations only in the non-PCI group. Specifically, there were negative correlations between %increase and fasting blood sugar (r = -0.64, P < 0.05), hemoglobin A1c (r = -0.74, P < 0.05), total cholesterol (r = -0.87, P < 0.05), triglyceride (r = -0.71, P < 0.05), and low-density lipoprotein cholesterol (r = -0.92, P < 0.005), respectively.

CONCLUSIONS

Although impaired glucose tolerance patients with a PCI-treated coronary stenosis showed preserved response to CPT, the %increase negatively correlated with risk factors in the non-PCI segments. Therefore, coronary risk factors may affect CAD lesions in PCI-treated patients.

Pleiotropic role for monocyte C-fms protein in response to vascular injury: potential therapeutic target

OBJECTIVES

We examined the role of C-fms+ cells in response to vascular injury with a focus on the temporal and spatial platelet interactions, monocyte survival and proliferation within the evolving neointimal lesion and monocyte proliferation within the circulation and specified monocyte reservoir sites. Finally, we investigated the therapeutic effect of C-fms kinase inhibition (CFKI) on neointimal hyperplasia post vessel injury.

METHODS AND RESULTS

We utilized murine carotid-wire injury, a transgenic C-fms reporting mouse model, confocal microscopy, shear-flow studies, specific C-fms signalling inhibition to determine the activation, mobilization and recruitment of C-fms+ monocytes in the context of early and late vessel remodelling. C-fms+ cells were recruited as early as 4h and accumulated over time in the neointima following injury. Monocyte interaction with platelet thrombus under flow and in vivo, in addition to monocyte mobilisation into the circulation post-injury was impaired by CFKI administration. Sustained inhibition of C-fms over 1-2 weeks abrogated the neointimal response but preserved re-endothelialisation post-injury.

CONCLUSION

These data establish C-fms as a key regulator of the vascular response to injury and a potentially attractive therapeutic target in disease states where neointimal hyperplasia, monocyte activation and pathologic remodelling are prominent and endothelial homeostasis is desirable.

Vitamin D receptor: a new risk marker for clinical restenosis after percutaneous coronary intervention

OBJECTIVE

Restenosis is the main drawback of percutaneous coronary intervention (PCI). Inherited factors may explain part of the risk of restenosis. Recently, the vitamin D receptor (VDR) has been shown to be involved not only in bone metabolism but also in modulating immune responses and cell proliferation. Since the inflammatory response is implicated in restenosis, VDR-gene variants could therefore contribute to the risk of restenosis.

METHODS/RESULTS

Systematic genotyping for 15 haplotype tagging single-nucleotide polymorphisms (SNPs) of the VDR gene was performed with the high throughput TaqMan allelic discrimination assays in the Genetic Determinants of Restenosis (GENDER) population. A haplotype-based survival analysis revealed an association of haplotypes in blocks 2, 3 and 4 of the VDR-gene with the risk of clinical restenosis (p-values 0.01, 0.04 and 0.02 respectively). After adjustment for clinical risk factors for restenosis, the individual effect of the block 2 AA haplotype (p = 0.011) persisted.

CONCLUSIONS

The present study indicates that VDR plays a role in restenosis after PCI. Therefore, VDR genotype may be used as risk marker for restenosis and may contribute to individual patient screening prior to PCI in clinical practice.

Systemic inflammatory response to renal artery percutaneous angioplasty with stent placement and the risk for restenosis: a pilot study

PURPOSE

Time changes in plasma concentrations of six different cytokines were investigated to evaluate the inflammatory response to renal artery stent placement.

MATERIALS AND METHODS

A total of 22 patients (17 men; mean age, 66 years +/- 13) with ostial renal artery stenosis and poorly controlled hypertension treated with stent placement were studied. Blood samples were collected at baseline and at 24 hours and 6 months after the intervention. Plasma concentrations of (i) tumor necrosis factor-alpha, (ii) interleukin-6 (IL-6), (iii) monocyte chemoattractant protein-1, (iv) intercellular adhesion molecule-1, (v) vascular cell adhesion molecule-1, and (vi) regulated upon activatin normal T-cell expressed presumed secreted were measured. Restenosis diagnosed with imaging follow-up at 6 months was recorded. Plasma concentrations of the aforementioned cytokines were compared between patients with and without restenosis.

RESULTS

IL-6 concentration increased significantly 24 hours after stent placement (8.3 pg/mL +/- 1.24 vs. 2.76 pg/mL +/- 1.27 at baseline) and returned to baseline levels (2.6 pg/mL +/- 1.77) at 6-month follow-up (P < .0001). No significant changes occurred in the concentrations of any other cytokines at the three time points. Baseline and 6-month concentrations of IL-6 were significantly higher in patients with restenosis than in those without restenosis (8.13 pg/mL +/- 4 vs 0.75 pg/mL +/- 0.47 [P < .005] and 9.55 pg/mL +/- 6.5 vs 0.42 pg/mL +/- 0.35 [P < .02], respectively).

CONCLUSIONS

Renal artery angioplasty with stent placement induces an inflammatory response, as evidenced by increased IL-6 production. Additionally, IL-6 seems to identify patients prone to develop restenosis; therefore, it might be used as an early predictor of restenosis after renal angioplasty with stent placement. However, larger studies are required to confirm IL-6 as a potential predictor of restenosis.

M-CSF accelerates neointimal formation in the early phase after vascular injury in mice: the critical role of the SDF-1-CXCR4 system

OBJECTIVE

Since the macrophage colony-stimulating factor (M-CSF) has been shown to stimulate differentiation and proliferation of monocyte/macrophage lineage and to be involved in the process of neointimal formation after vascular injury, we tested the effects of M-CSF on the recruitment of bone marrow-derived progenitor cells in neointimal formation after vascular injury in mice.

METHODS AND RESULTS

Wire-mediated vascular injury was produced in the femoral artery of C57BL/6 mice. Recombinant human M-CSF [500 microg/(kg x day)] or saline (control) was administered for 10 consecutive days, starting 4 days before the injury. Treatment with M-CSF accelerated neointimal formation in the early phase after injury, and this neointimal lesion mainly consisted of bone marrow-derived cells. M-CSF treatment had no effect on the mobilization of endothelial progenitor cells (EPCs: CD34+/Flk-1+) and reendothelialization after injury. The stromal cell-derived factor-1 (SDF-1) was markedly expressed in the neointima and media after injury, whereas CXCR4+ cells were observed in the neointima. Further, a novel CXCR4 antagonist, AMD3100, significantly attenuated the M-CSF-induced neointimal formation.

CONCLUSIONS

These findings suggest that M-CSF accelerated neointimal formation after vascular injury via the SDF-1-CXCR4 system, and the inhibition of this system has therapeutic potential for the treatment of cardiovascular diseases.

Genetic inflammatory factors predict restenosis after percutaneous coronary interventions

BACKGROUND

Restenosis is a negative effect of percutaneous coronary intervention (PCI). No clinical factors are available that allow good risk stratification. However, evidence exists that genetic factors are important in the restenotic process as well as in the process of inflammation, a pivotal factor in restenosis. Association studies have identified genes that may predispose to restenosis, but confirmation by large prospective studies is lacking. Our aim was to identify polymorphisms and haplotypes in genes involved in inflammatory pathways that predispose to restenosis.

METHODS AND RESULTS

The GENetic DEterminants of Restenosis (GENDER) project is a multicenter prospective study, including 3104 consecutive patients after successful PCI. Forty-eight polymorphisms in 34 genes in pathways possibly involved in the inflammatory process were analyzed. The 16Gly variant of the beta2-adrenergic receptor gave an increased risk of target vessel revascularization (TVR). The rare alleles of the CD14 gene (-260T/T), colony-stimulating factor 2 gene (117Thr/Thr), and eotaxin gene (-1328A/A) were associated with decreased risk of TVR. However, through the use of multiple testing corrections with permutation analysis, the probability of finding 4 significant markers by chance was 12%.

CONCLUSIONS

Polymorphisms in 4 genes considered involved in the inflammatory reaction showed an association with TVR after PCI. Our results may contribute to the unraveling of the restenotic process. Given the explorative nature of this analysis, our results need to be replicated in other studies.

Tumor necrosis factor-alpha plays an important role in restenosis development

Genetic factors appear to be important in the restenotic process after percutaneous coronary intervention (PCI), as well as in inflammation, a pivotal factor in restenosis. TNFalpha, a key regulator of inflammatory responses, may exert critical influence on the development of restenosis after PCI. The GENetic DEterminants of Restenosis (GENDER) project included 3104 patients who underwent a successful PCI. Systematic genotyping for six polymorphisms in the TNFalpha gene was performed. The role of TNFalpha in restenosis was also assessed in ApoE*3-Leiden mice, TNFalpha knockout mice, and by local delivery of a TNFalpha biosynthesis inhibitor, thalidomide. The -238G-1031T haplotype of the TNFalpha gene increased clinical and angiographic risk of restenosis (P=0.02 and P=0.002, respectively). In a mouse model of reactive stenosis, arterial TNFalpha mRNA was significantly time-dependently up-regulated. Mice lacking TNFalpha or treated locally with thalidomide showed a reduction in reactive stenosis (P=0.01 and P=0.005, respectively). Clinical and preclinical data indicate that TNFalpha plays an important role in restenosis. Therefore, TNFalpha genotype may be used as a risk marker for restenosis and may contribute to individual patient screening prior to PCI in clinical practice. Inhibition of TNFalpha may be an anti-restenotic target strategy.

Lipoprotein lipase gene polymorphisms and the risk of target vessel revascularization after percutaneous coronary intervention

OBJECTIVES

We sought to identify polymorphisms in genes that predispose to restenosis.

BACKGROUND

Variations in the lipoprotein lipase (LPL) gene have been implicated in a number of pathophysiologic conditions associated with coronary heart disease. The present study examines the impact of polymorphisms in the LPL gene on restenosis (defined by target vessel revascularization [TVR]) in a large patient population undergoing percutaneous coronary intervention (PCI). A mouse model for restenosis was used to further investigate LPL's role in restenosis.

METHODS

The GENetic DEterminants of Restenosis (GENDER) project is a multicenter, prospective study design that enrolled 3,104 consecutive patients after successful PCI. These patients were genotyped for four different LPL gene polymorphisms. In apolipoprotein E (ApoE)*3-Leiden transgenic mice, arterial messenger ribonucleic acid (mRNA) was used to assess LPL expression during a cuff-induced restenotic process.

RESULTS

Using multivariable analysis, carriers of the 447Ter allele of the LPL enzyme showed a lower risk of TVR compared with 447Ser homozygotes (p = 0.005). In the mouse model, LPL mRNA levels were increased 40-fold compared with control arteries at 6 h after cuff placement.

CONCLUSIONS

The LPL C/G polymorphism (Ser447Ter), resulting in a truncation of the two C-terminal amino acids of the mature LPL protein, appears to be an important protective factor for TVR in humans. The role of LPL in this process was further established in a mouse model, where LPL expression was very strongly up-regulated in the target arterial wall, suggesting a contribution of this lipolytic enzyme to restenosis. Possibly, LPL Ser447Ter genotyping may lead to better risk stratification and tailored therapy in the prevention of restenosis after PCI.

Peroxisome proliferator-activated receptor-gamma agonist rosiglitazone reduces clinical inflammatory responses in type 2 diabetes with coronary artery disease after coronary angioplasty

Rosiglitazone, an agonist of peroxisome proliferator-activated receptor-gamma (PPAR gamma ), is an insulin-sensitizing antidiabetic agent and inhibits restenosis in animal blood vessels. However, its benefit for patients with type 2 diabetes and coronary artery disease (CAD) after percutaneous coronary intervention is unknown. Patients with diabetes and CAD who had undergone percutaneous coronary intervention were randomized to either receive or not receive rosiglitazone (4 mg/d) for 6 months. After 6 months of rosiglitazone treatment, the plasma levels of fasting glucose and insulin and those of hemoglobin A1C and homeostasis model assessment of insulin resistance were significantly decreased in the rosiglitazone group as compared with baseline levels and those in the control group. After 2 and 6 months of rosiglitazone treatment, the plasma level of high-density lipoprotein was significantly increased in the rosiglitazone group. In addition, plasma levels of monocyte chemoattractant protein-1 and C-reactive protein and hyperresponsiveness of low-dose lipopolysaccharide-induced monocyte chemoattractant protein-1 secretion from monocytes were reduced. Furthermore, the occurrence of coronary events was significantly decreased in the rosiglitazone group at 6-month follow-up. Our data indicate that rosiglitazone may protect the vascular wall through not only improving the features of metabolic disorders but also reducing proinflammatory responses and the occurrence of coronary events in patients with diabetes and CAD after percutaneous coronary intervention.

Vascular brachytherapy in renal artery restenosis

PURPOSE OF REVIEW

As renal artery stenting becomes more commonly performed, the prevalence of renal artery in-stent restenosis will increase. Intracoronary brachytherapy is the only adjuvant therapy that has been shown to reduce the incidence of recurrent restenosis. This review addresses the mechanisms that make brachytherapy an effective tool for restenosis and its application to renal arteries.

RECENT FINDINGS

To date, the literature on renal artery brachytherapy for restenosis consists of several singular case reports and two case series. The first series of 13 patients had a 20% restenosis rate 1 year after brachytherapy, when Doppler ultrasound was used for follow-up monitoring. A report of a series of 5 patients, published this year, used surrogate markers for assessing efficacy as endpoints and found a similar restenosis rate.

SUMMARY

These series and case reports demonstrate that renal brachytherapy is feasible and safe. Comments on efficacy must await a randomized trial or accumulation of more anecdotal data.

Serum concentrations of vascular endothelial growth factor and monocyte-colony stimulating factor in peripheral arterial disease

Vascular endothelial growth factor (VEGF) strongly promotes angiogenesis, and monocyte-colony stimulating factor (M-CSF) regulates the differentiation, proliferation, and survival of monocytes. Both VEGF and M-CSF are expressed in atherosclerotic lesions. The present study was performed to clarify the role of VEGF and M-CSF in the development of peripheral artery disease (PAD). The serum VEGF and M-CSF concentrations were determined in patients with arteriosclerosis obliterans (ASO) and thromboangitis obliterans (TAO). In both patient groups the serum VEGF concentrations were significantly higher than those in the control subjects. In contrast, the serum M-CSF concentrations in the ASO patients were significantly higher than those in both the TAO patients and control subjects, but there were no differences in the M-CSF concentrations between the TAO patients and control subjects. There was no correlation between the serum concentrations of VEGF and M-CSF. In conclusion, the serum VEGF concentration was increased in ASO and TAO patients, but increased concentration of M-CSF was seen only in ASO patients. These results may reflect a difference between ASO and TAO in disease pathogenesis.

Inhibition of the renin-angiotensin system: no effect on circulating macrophage colony-stimulating factor levels in acute myocardial infarction

Macrophage colony-stimulating factor, which induces proliferation and differentiation, and activation of monocytes and macrophages, plays an important role in the vulnerability of atheromatous plaques as well as the formation of atherosclerotic lesions. We measured serum concentrations of macrophage colony-stimulating factor in patients with acute myocardial infarction and also investigated the effects of early administration of angiotensin-converting enzyme inhibitor and angiotensin receptor blocker on circulating macrophage colony-stimulating factor levels in these patients. The patients were divided randomly into 3 therapeutic groups; perindopril, candesartan, and control (without perindopril and candesartan) groups, and the drugs were administered within 24 to 36 hours after the onset of acute myocardial infarction. Serum macrophage colony-stimulating factor concentrations in acute myocardial infarction patients at the time of admission were significantly higher than those in healthy control subjects. The macrophage colony-stimulating factor levels in the patients decreased gradually after admission, but remained significantly higher than those in control subjects for 14 days. There were no significant differences in serum macrophage colony-stimulating factor levels among the 3 therapeutic groups during this study period. In conclusion, circulating macrophage colony-stimulating factor levels are elevated during the course of acute myocardial infarction, and inhibition of the renin-angiotensin system by angiotensin-converting enzyme inhibitor or angiotensin receptor blocker does not affect these levels.

Activated platelets trigger an inflammatory response and enhance migration of aortic smooth muscle cells

OBJECTIVE

Exposure of the subendothelium to flowing blood following rupture of atherosclerotic lesions or during balloon angioplasty initiates platelet adhesion to the vascular wall. Because activated platelets release proinflammatory mediators (e.g., interleukin (IL)-1beta) and secrete growth factors, platelet adhesion to the subendothelial matrix might contribute to the recruitment of inflammatory cells and promote migration and proliferation of vascular smooth muscle cells (SMCs).

METHODS AND RESULTS

Here, we demonstrate that incubation of cultured monolayers of aortic SMCs with alpha-thrombin-activated platelets significantly enhances the secretion of monocyte chemoattractant protein-1 (MCP-1) (P<0.05) and promotes SMC migration (P<0.05). Platelet-induced secretion of MCP-1 was abolished by anti-IL-1alpha and beta monoclonal antibodies or the IL-1 receptor antagonist (IL-1RA). In contrast, platelet-mediated SMC migration was attenuated only by anti-platelet-derived growth factor (PDGF)-mAb but not by IL-1RA. Correspondingly, recombinant human interleukin-1 (rhIL-1) beta increased MCP release by SMCs but had no effect on SMC migration. Platelet-mediated MCP secretion by SMCs involved the activation and nuclear translocation of the transcription factor nuclear factor-kappaB (NF-kappaB).

CONCLUSION

Therefore, platelet adhesion to the subendothelium increases the chemotactic and migratory properties of SMC and is likely to contribute substantially to the process of atherosclerosis and vessel (re-)stenosis.

Peripheral vascular brachytherapy

Ongoing advances in peripheral endovascular technology have been met with disappointing results because of restenosis within the treated vessel. In particular, stent balloon angioplasty of peripheral vessels has yet to achieve patency rates that approximate conventional treatment in the long term. Recent advances in stent, balloon, and wire construction include the incorporation of radioactive substances in an attempt to ameliorate the inflammatory response provoked by typical endovascular manipulation, a technique termed vascular brachytherapy. gamma- and beta-isotopes and external beam radiation target the very cell population whose activity results in the development of neointimal hyperplasia. Although most clinical research examining the efficacy of vascular brachytherapy has emerged from the coronary artery literature, the use of vascular brachytherapy also has been examined in the peripheral arterial tree and has shown promising results. Current data indicate that vascular brachytherapy is a safe and accessible adjunctive endovascular maneuver that may improve the short-term patency rate of peripheral endovascular applications. The effects on long-term patency rates remain indeterminate compared to conventional therapy.

Increased levels of monocyte-related cytokines in patients with unstable angina

Inflammatory cytokines play important roles in coronary artery disease. We investigated the clinical significance of monocyte-related cytokine expression in patients with angina pectoris. We studied 26 patients with stable effort angina and 20 patients with unstable angina in whom stenotic lesions of the coronary arteries were confirmed by selective coronary angiography. Plasma levels of interleukin-6 (IL-6), macrophage colony stimulating factor (MCSF), and monocyte chemoattractant protein-1 (MCP-1) were measured. Plasma levels of IL-6, MCSF, and MCP-1 in patients with unstable angina were significantly higher than those in patients with stable angina or control subjects. Patients with unstable angina were further divided into sub-groups according to their clinical classification; Levels of IL-6, MCSF, and MCP-1 in patients, who had anginal attacks at rest within the 48 h prior to admission (Braunwald class IIIB) were significantly higher than those in patients, who did not have attacks at rest (class IB). Five unstable patients, who were refractory to medical therapy and were referred for emergency coronary revascularization showed marked elevation of plasma MCSF and MCP-1 levels. In conclusion, plasma levels of monocyte-related cytokines were elevated in unstable angina. These increases were marked in patients with unstable angina with recent ischemic attack at rest, suggesting that activation of monocytes is involved in vulnerability of underlying atheromatous plaque.