Effect of activated platelets on expression of cytokines in peripheral blood mononuclear cells – potential role of prostaglandin E2

Platelets may act as inflammatory cells. To study the effects of soluble and cell-bound platelet factors on the expression of several cytokines and related mediators in leukocytes, peripheral blood mononuclear cells (PBMC) were incubated with platelet-free supernatants from SFLLRN-activated platelet-rich plasma (PRP) or SFLLRN-activated PRP in itself. Our main findings were: (i) the gene expression of several chemokines and some cytokines were markedly increased by both activated PRP and supernatants, as also confirmed at the protein level for IL-6, IL-8 and MIP-1α; (ii) the selective protein kinase A type I (PKAI) antagonist Rp-8-Br-cAMP reduced this platelet-induced expression of IL-6, IL-8 and MIP-1α in PBMC, suggesting a role of cAMP/PKAI mediated mechanisms in this interaction; (iii) PGE2 dose-dependently increased the release of IL-6, IL-8 and MIP-1α from PBMC mimicking the effect of activated platelets. Furthermore, activated platelets released comparable amounts of PGE2, suggesting that platelet-derived PGE2 could interact with PBMC in co-cultures; (iv) IL-10 inhibited the platelet-inducing effect on IL-6, IL-8 and MIP-1α in PBMC, and notably, the addition PGE2 totally abolished this IL-10 effect suggesting that the suppressive effect of IL-10 on the plateletinduced activation of PBMC might at least partly involve PGE2related mechanisms. The present study supports a view of platelets as inflammatory cells, and suggests a potential role of platelet-derived PGE2 in platelet-induced inflammatory responses.

High levels and inflammatory effects of soluble CXC ligand 16 (CXCL16) in coronary artery disease: down-regulatory effects of statins

AIMS

CXC ligand 16 (CXCL16) may be involved in inflammation and lipid metabolism, and we hypothesized a role for this chemokine in coronary artery disease (CAD).

METHODS AND RESULTS

We performed clinical studies in CAD patients as well as experimental studies in cells with relevance to atherogenesis [i.e. endothelial cells, vascular smooth muscle cells (SMC), and peripheral blood mononuclear cells (PBMC)]. We also examined the ability of HMG-CoA reductase inhibitors (statins) to modulate CXCL16 levels both in vivo and in vitro. Our main findings were: (i) patients with stable (n = 40) and unstable (n = 40) angina had elevated plasma levels of CXCL16 compared with controls (n = 20); (ii) low-dose simvastatin (20 mg qd, n = 15) and high-dose atorvastatin (80 mg qd, n = 9) down-regulated plasma levels of CXCL16 during 6 months of therapy; (iii) in vitro, atorvastatin significantly decreased the interleukin (IL)-1beta-mediated release of CXCL16 from PBMC and endothelial cells; (iv) attenuating effect of atorvastatin on the IL-1beta-mediated release of CXCL16 in PBMC seems to involve post-transcriptional modulation as well as down-regulation of CXCL16 release through inhibition of the protease a disintegrin and metalloproteinase 10 (ADAM10); (v) soluble CXCL16 increased the release of IL-8, monocyte chemoattractant peptide 1, and matrix metalloproteinases in vascular SMC and increased the release of IL-8 and monocyte chemoattractant peptide 1 in PBMC, with particularly enhancing effects in cells from CAD patients.

CONCLUSION

Our findings suggest that soluble CXCL16 could be linked to atherogenesis not only as a marker of inflammation, but also as a potential inflammatory mediator.

A potential role of the CXC chemokine GROalpha in atherosclerosis and plaque destabilization: downregulatory effects of statins

OBJECTIVE

We examined the role of the CXCR2 ligand growth-related oncogene (GRO) alpha in human atherosclerosis.

METHODS AND RESULTS

GROalpha levels were examined by enzyme immunoassay, real-time quantitative RT-PCR, and cDNA microarrays. The in vitro effect of statins on GROalpha was examined in endothelial cells and THP-1 macrophages. Our main findings were: (1) GROalpha was among the 10 most differentially expressed transcripts comparing peripheral blood mononuclear cells (PBMCs) from patients with coronary artery disease (CAD) and healthy controls. (2) Both patients with stable (n=41) and particularly those with unstable (n=47) angina had increased plasma levels of GROalpha comparing controls (n=20). (3) We found increased expression of GROalpha within symptomatic carotid plaques, located to macrophages and endothelial cells. (4) GROalpha enhanced the release of matrix metalloproteinases in vascular smooth muscle cells, and increased the binding of acetylated LDL in macrophages. (5) Atorvastatin downregulated GROalpha levels as shown both in vitro in endothelial cells and macrophages and in vivo in PBMCs from CAD patients. (6) The effect on GROalpha in endothelial cells involved increased storage and reduced secretion of GROalpha.

CONCLUSIONS

GROalpha could be involved in atherogenesis and plaque destabilization, potentially contributing to inflammation, matrix degradation, and lipid accumulation within the atherosclerotic lesion.

Potential role for immunomodulatory therapy in atherosclerotic plaque stabilisation

Our understanding of the mechanisms underlying acute coronary syndromes has evolved beyond the view that this syndrome reflects a progressive collection of lipids and cellular debris in the vascular wall. Current evidence has implicated a role for inflammation in the pathogenesis of this process. Thus, inflammatory cytokines may attenuate interstitial collagen synthesis, increase matrix degradation and promote apoptosis in several atheroma-associated cell types, and all these cellular events may enhance plaque vulnerability. Recently, a series of experimental studies have reported the plaque-stabilising effects of immunomodulatory therapy such as chemokine blockade, anti-CD40 ligand and IL-10. It is conceivable that some of these approaches will be tested clinically and, if successful, they could provide novel treatment strategies for atherosclerotic plaque stabilisation.

Enhanced Expression of the Homeostatic Chemokines CCL19 and CCL21 in Clinical and Experimental Atherosclerosis

Objective— Based on their role in T-cell homing into nonlymphoid tissue, we examined the role of the homeostatic chemokines CCL19 and CCL21 and their common receptor CCR7 in coronary artery disease (CAD).

Methods and Results— We performed studies in patients with stable (n=40) and unstable (n=40) angina and healthy controls (n=20), in vitro studies in T-cells and macrophages, and studies in apolipoprotein-E–deficient (ApoE −/− ) mice and human atherosclerotic carotid plaques. We found increased levels of CCL19 and CCL21 within the atherosclerotic lesions of the ApoE −/− mice, in human atherosclerotic carotid plaques, and in plasma of CAD patients. Whereas strong CCR7 expression was seen in T-cells from murine and human atherosclerotic plaques, circulating T-cells from angina patients showed decreased CCR7 expression. CCL19 and CCL21 promoted an inflammatory phenotype in T-cells and macrophages and increased matrix metalloproteinase (MMP) and tissue factor levels in the latter cell type. Although aggressive statin therapy increased CCR7 and decreased CCL19/CCL21 levels in peripheral blood from CAD patients, conventional therapy did not.

Conclusions— The abnormal regulation of CCL19 and CCL21 and their common receptor in atherosclerosis could contribute to disease progression by recruiting T-cells and macrophages to the atherosclerotic lesions and by promoting inflammatory responses in these cells.

Increased Levels of Neutrophil-Activating Peptide-2 in Acute Coronary Syndromes

OBJECTIVES

We sought to investigate the role of the CXC chemokine neutrophil-activating peptide-2 (NAP-2) in atherogenesis and plaque destabilization.

BACKGROUND

Chemokines are involved in atherogenesis, but the role of NAP-2 in atherosclerotic disorders is unclear. Based on its potential pro-atherogenic properties, we hypothesized a pathogenic role for NAP-2 in coronary artery disease.

METHODS

We tested this hypothesis by differential experimental approaches including studies in patients with stable (n = 40) and unstable angina (n = 40) and healthy control subjects (n = 20).

RESULTS

The following results were discovered: 1) patients with stable, and particularly those with unstable, angina had markedly raised plasma levels of NAP-2 compared with control subjects, accompanied by increased expression of CXC receptor 2 in monocytes; 2) platelets, but also peripheral blood mononuclear cells (PBMCs), released large amounts of NAP-2 upon stimulation, with a particularly prominent PBMC response in unstable angina; 3) NAP-2 protein was detected in macrophages and smooth muscle cells of atherosclerotic plaques and in monocytes and platelets of coronary thrombi; 4) in vitro, recombinant and platelet-derived NAP-2 increased the expression of adhesion molecules and chemokines in endothelial cells; and 5) whereas aspirin reduced plasma levels of NAP-2, statin therapy increased NAP-2 with stimulating effects both on platelets and leukocytes.

CONCLUSIONS

Our findings suggest that NAP-2 has the potential to induce inflammatory responses within the atherosclerotic plaque. By its ability to promote leukocyte and endothelial cell activation, such a NAP-2-driven inflammation could promote plaque rupture and acute coronary syndromes.

Clopidogrel increases expression of chemokines in peripheral blood mononuclear cells in patients with coronary artery disease: results of a double-blind placebo-controlled study

BACKGROUND

Chemokines and platelet activation are both important in atherogenesis. Platelet inhibitors are widely used in coronary artery disease (CAD), and we hypothesized that the platelet inhibitor clopidogrel could modify chemokines in CAD patients.

OBJECTIVES

We sought to investigate the effect of clopidogrel on the expression of chemokines and chemokine receptors in peripheral blood mononuclear cells (PBMC) in CAD patients.

PATIENTS/METHODS

Thirty-seven patients with stable angina were randomized to clopidogrel (n = 18) or placebo (n = 19). PBMC, blood platelets and plasma were collected at baseline and after 7-10 days in the patients, and in 10 healthy controls. mRNA levels of chemokines and chemokine receptors in PBMC were analyzed by ribonuclease protection assays and real-time reverse transcriptase polymerase chain reaction. Platelet activation was studied by flow cytometry.

RESULTS

(i) At baseline, the gene expression of the regulated on activation normally T-cell expressed and secreted (RANTES) chemokines and macrophage inflammatory peptide (MIP)-1beta in PBMC, the expression of CD62P and CD63 on platelets and the levels of platelet-derived microparticles (PMP) were elevated in angina patients comparing healthy controls; (ii) markers of platelet activation were either reduced (CD63) or unchanged (CD62P, PMP, beta-thromboglobulin) during clopidogrel therapy; (iii) in contrast, clopidogrel significantly up-regulated the gene expression of RANTES and MIP-1beta in PBMC, while no changes were found in the placebo group; (iv) a stable adenosine 5'-diphosphate metabolite attenuated the release of MIP-1beta, but not of RANTES, from activated PBMC in vitro.

CONCLUSIONS

Even if we do not argue against a beneficial role for clopidogrel in CAD, our findings may suggest potential inflammatory effects of clopidogrel in CAD.

Inflammation in coronary artery disease: potential role for immunomodulatory therapy

Understanding of the mechanisms underlying atherosclerotic disorders has evolved beyond the view of a progressive collection of lipids and cellular debris in the vascular wall. Current evidence has implicated inflammatory pathways as an important pathogenic mechanism in atherogenesis and plaque destabilization. Although not necessarily the primary event, inflammation and cytokine activation during plaque formation and destabilization may represent a common final pathway to various stimuli. Thus, it seems that not only 'new' risk factors, such as infections with various microorganisms, but also classic risk factors for cardiovascular disease, such as hyperlipidemia, hypertension and diabetes, may promote their atherogenic effects through inflammatory responses. Indeed, recent reports have suggested that traditional cardiovascular medications may attenuate atherogenesis and enhance plaque stability, at least partly through anti-inflammatory mechanisms. However, uncovering the inflammatory pathways in atherosclerosis has raised the possibility that newer treatment modalities should be more directly targeted against inflammatory mediators. Recently, a series of experimental studies have reported reduction of atherosclerosis by immunomodulatory therapy, such as chemokine blockade, interleukin-10 and immunization/vaccination against oxidized low-density lipoprotein and heat-shock protein. It is conceivable that some of these approaches will be tested clinically and, if successful, they could provide novel treatment strategies in coronary artery disease in humans.

Chemokines in Children With Heterozygous Familiar Hypercholesterolemia

OBJECTIVE

Increasing data support the involvement of chemokines in atherogenesis. However, although several studies have shown increased chemokine levels in adult patients, the literature is virtually devoid of data on chemokines in children with hypercholesterolemia.

METHODS AND RESULTS

We examined the gene expression of chemokines in peripheral blood mononuclear cells (PBMCs) from clinically healthy children with and without heterozygous familial hypercholesterolemia (FH). Our main findings were: (1) compared with healthy controls, PBMCs from FH children showed significantly higher mRNA levels of RANTES, but not of the other examined chemokines; (2) an opposite pattern was seen in adult FH subjects, with markedly enhanced expression of macrophage inflammatory peptide-1alpha, but not of RANTES; (3) this increased gene expression of RANTES in PBMCs from FH children seemed to reflect enhanced RANTES expression in monocytes but not in T cells; (4) FH children also had raised serum levels of neopterin, additionally suggesting monocyte/macrophage activation in these children; and (5) PBMCs from both FH children and controls showed enhanced release of interleukin 8 on RANTES stimulation in vitro.

CONCLUSIONS

Our findings support a role of inflammation also in the early stages of atherogenesis possibly involving monocyte-derived RANTES as an important mediator.

Expression of Fractalkine (CX3CL1) and its Receptor, CX3CR1, Is Elevated in Coronary Artery Disease and Is Reduced During Statin Therapy

OBJECTIVE

Recent data derived primarily from studies in animal models suggest that fractalkine (CX3CL1) and its cognate receptor, CX3CR1, play a role in atherogenesis. We, therefore, hypothesized that enhanced CX3CL1/CX3CR1 expression may promote atherogenesis in patients with coronary artery disease (CAD).

METHODS AND RESULTS

We examined the plasma levels of CX3CL1 and CX3CR1 expression in peripheral blood mononuclear cells (PBMC) in various CAD populations (30 patients with previous myocardial infarction, 40 patients with stable angina, 40 patients with unstable angina, and a total of 35 controls) and used various experimental approaches to characterize CX3CL1-mediated leukocyte responses. We found that the plasma levels of CX3CL1 are greatly increased in CAD, particularly in unstable disease. The parallel increase of CX3CR1 expression in PBMC was predominantly attributable to an expansion of the (CX3CR1+)(CD3+)(CD8+) T cell subset and was associated with enhanced chemotactic, adhesive, and inflammatory responses to CX3CL1. Statin therapy for 6 months reduced the expression of CX3CL1 and CX3CR1, reaching statistical significance for both parameters only during aggressive (atorvastatin, 80 mg qd) but not conventional (simvastatin, 20 mg qd) therapy. Consequently, the functional responses of the PBMC to CX3CL1 including migration, adhesion, and secretion of interleukin-8 were attenuated by the treatments.

CONCLUSIONS

Our results suggest that the CX3CL1/CX3CR1 dyad may contribute to atherogenesis and plaque destabilization in human CAD.

Interleukin-10 enhances the oxidized LDL-induced foam cell formation of macrophages by antiapoptotic mechanisms

Interleukin (IL)-10 may have a therapeutic potential in atherosclerosis, but its mechanisms of action have not been clarified. Foam cell formation is a key event in atherogenesis, and apoptosis of these lipid-laden cells may promote plaque destabilization. We sought to explore whether IL-10 could have plaque-stabilizing properties in acute coronary syndromes (ACS). We studied the effect of IL-10 on oxidized low density lipoprotein (oxLDL)-stimulated THP-1 cells and monocyte-derived macrophages from ACS patients and healthy controls using different experimental approaches. Our main findings were: i) IL-10 enhances lipid accumulation in oxLDL-stimulated THP-1 macrophages, at least partly by counteracting oxLDL-induced apoptosis; ii) This antiapoptotic effect of IL-10 involves increased expression of the antiapoptotic genes Bfl-1 and Mcl-1, accompanied by protective effects on mitochondria function; iii) By silencing Bfl-1 and Mcl-1 genes using siRNAs, we were able to abolish this IL-10-mediated effect on lipid accumulation; iv) IL-10 also induced lipid accumulation in oxLDL-stimulated macrophages from patients with ACS, but not in macrophages from healthy controls; v) In ACS patients, this enhancing effect of IL-10 on lipid accumulation was accompanied by enhanced Mcl-1 expression. No such antiapoptotic effect was seen in macrophages from healthy controls. These findings suggest a new mechanism for the effect of IL-10 in atherosclerosis, possibly contributing to plaque stabilization.

Potential anti-inflammatory role of activin A in acute coronary syndromes

OBJECTIVES

We sought to investigate whether activin A could be involved in the immunopathogenesis of acute coronary syndromes.

BACKGROUND

Inflammatory mechanisms seem to play a pathogenic role in atherosclerosis and acute coronary syndromes, but the actual mediators have not been fully identified. Activin A, a pleiotropic member of the transforming growth factor-beta cytokine family, has recently been suggested to play a role in inflammation.

METHODS

We examined the role of activin A and its endogenous inhibitor follistatin in patients with stable (n = 26) and unstable angina (n = 20) and healthy control subjects (n = 20) by different experimental approaches.

RESULTS

1) Patients with stable angina had raised activin A concentrations, as assessed by protein levels in serum and messenger ribonucleic acid levels in peripheral blood mononuclear cells (PBMCs). 2) Although several activin A-related mediators were upregulated in PBMCs from patients with stable angina compared with controls (i.e., activin A and Smad3), no changes or even downregulation (i.e., Smad2) were seen in unstable disease. 3) The activin type II receptors, representing the primary ligand-binding proteins, were downregulated in unstable compared with stable angina. 4) Percutaneous coronary intervention induced a decrease in the activin A/follistatin ratio, suggesting downregulatory effects on activin A activity. 5) Although activin A dose-dependently suppressed the release of inflammatory cytokines from PBMCs in angina patients, an opposite effect was found in healthy controls.

CONCLUSIONS

Our findings suggest an anti-inflammatory potential of activin A in angina patients, and such effects may be of particular relevance in unstable angina in which several of the activin parameters were downregulated.

Increased Expression of Interleukin-1 in Coronary Artery Disease With Downregulatory Effects of HMG-CoA Reductase Inhibitors

Background— Inflammation is important in atherogenesis. Interleukin (IL)-1 is the prototypic inflammatory cytokine. We hypothesized a dysbalance between inflammatory and anti-inflammatory mediators in the IL-1 family in coronary artery disease (CAD) and a possible modulation of these mediators by HMG-CoA inhibitors (statins).

Methods and Results— In a microarray screening experiment examining peripheral blood mononuclear cells (PBMCs) from 6 CAD patients and 4 healthy control subjects, IL-1β was identified as 1 of 25 genes whose expression were upregulated in CAD and downregulated by statins. In the following, we studied the role of IL-1β and related mediators in CAD. Our major findings were as follows. (1) Although mRNA levels of IL-1α and IL-1β were markedly reduced in PBMCs from CAD patients after 6 months of simvastatin (20 mg/d, n=15) and atorvastatin (80 mg/d, n=15) therapy, the reduction in IL-1 receptor antagonist (IL-1Ra) was more modest. Statins also reduced the spontaneous release of IL-1β and IL-1Ra from PBMCs in CAD patients. (2) mRNA levels of IL-1α, IL-1β, and IL-1Ra were increased in PBMCs from patients with stable (n=20) and unstable (n=20) angina compared with healthy control subjects (n=15). Although the unstable patients had particularly high levels of IL-1β and IL-1α, IL-1Ra was not correspondingly increased. (3) IL-1β induced release of proatherogenic cytokines from PBMCs, whereas atorvastatin partly abolished this effect.

Conclusions— Our findings suggest that cytokines in the IL-1 family may represent therapeutic targets in CAD. The ability of statins to modulate these cytokines in an anti-inflammatory direction underscores their immunomodulatory potential.

8-isoprostane increases expression of interleukin-8 in human macrophages through activation of mitogen-activated protein kinases

BACKGROUND AND OBJECTIVES

8-isoprostane is a marker of oxidative stress in vivo and increased plasma and urine levels are found in patients with vascular disease and in atherosclerotic plaques. Inflammatory chemokines such as interleukin (IL)-8 seem to play an important pathogenic role in atherogenesis. We therefore investigated the effects of 8-isoprostane on the expression of inflammatory chemokines with consciousness on IL-8 (mRNA and protein) in human macrophages. In addition, we studied the involvement of mitogen-activated protein kinases (ERK 1/2 and p38 MAPK) and nuclear factor-kappaB (NF-kappaB) in this process.

METHODS AND RESULTS

8-isoprostane (10 microM) induced IL-8 expression (mRNA and protein), measured by real-time quantitative RT-PCR and enzyme immunoassay, respectively, in both THP-1 macrophages and human monocyte-derived macrophages. Moreover, 8-isoprostane increased mRNA expression of macrophage inflammatory protein-1alpha as determined by RNase protection assay. In this process, 8-isoprostane induced the activation of two major MAP-kinases; ERK 1/2 and p38 MAPK. Furthermore, the ERK 1/2 inhibitor, PD98059, and the p38 MAPK inhibitor, SB203580, markedly reduced 8-isoprostane-induced IL-8 expression (mRNA and protein), while inhibition of NF-kappaB activation and translocation had no significant effect on IL-8 expression.

CONCLUSIONS

We show that 8-isoprostane increases IL-8 expression in human macrophages involving both ERK 1/2 and p38 MAPK, but not NF-kappaB signaling pathway. These findings further support a link between oxidative stress/lipid peroxidation and inflammation in human macrophages and suggest a role for 8-isoprostane in this process. This 8-isoprostane-induced chemokine expression might be involved in the pathogenesis of atherosclerosis as well as other inflammatory disorders.

Interleukin-7-mediated inflammation in unstable angina: possible role of chemokines and platelets

BACKGROUND

Atherogenesis and plaque destabilization involve immune-mediated mechanisms, but the actual mediators have not been fully clarified. Interleukin (IL)-7 is a regulator of T-cell homeostasis but also may be involved in inflammation. We hypothesized that IL-7 could be involved in the inflammatory processes observed in atherosclerosis and acute coronary syndromes.

METHODS AND RESULTS

To study the role of IL-7 in coronary artery disease, we analyzed IL-7 levels and the effect of this cytokine on inflammatory mediators in patients with stable and unstable angina and in healthy control subjects. Our major findings were (1) Plasma levels of IL-7 were significantly increased in patients with stable (n=30) and unstable angina (n=30) comparing healthy control subjects (n=20), particularly in those with unstable disease. (2) Increased release from activated platelets appeared to be a major contributor to the raised IL-7 levels in patients with angina. (3) IL-7 enhanced the expression of several inflammatory chemokines in peripheral blood mononuclear cells from both healthy control subjects and patients with angina, particularly in those with unstable disease. Similar effects were seen in monocytes but not in T cells. (4) MIP-1alpha further increased the release of IL-7 from platelets in a dose-dependent manner. (5) Aspirin reduced both the spontaneous and the SFLLRN-stimulated release of IL-7 from platelets, and when administered to healthy control subjects for 7 days (160 mg qd), it reduced plasma levels of IL-7.

CONCLUSIONS

Our findings suggest a role for IL-7-driven inflammation in atherogenesis and the promotion of clinical instability in coronary artery disease involving interactions between platelets, monocytes, and chemokines.

Raised serum levels of interleukin-18 is associated with disease progression and may contribute to virological treatment failure in HIV-1-infected patients

To gain further insight into the possible role of interleukin (IL)-18 in HIV-1 infection we examined serum levels of IL-18 in various clinical and immunological stages of HIV-1 infection during cross-sectional (n = 41) and longitudinal testing (n = 20) and during HAART (n = 21, 24 months follow-up). Our main findings were that HIV-1-infected patients had significantly raised IL-18 levels comparing healthy controls, particularly in those with advanced disease, that while HAART induced a marked decline in IL-18, virological treatment failure was associated with persistently raised IL-18 levels during such therapy and that our in vitro experiments showed an IL-18-mediated up-regulation of the HIV-1 coreceptor CXCR4 and the pro-apoptotic mediator TRAIL in PBMC from HIV-1-infected patients receiving HAART. HIV-1 infection appears to be characterized by persistently raised IL-18 levels and during HAART, such a pattern was associated with virological treatment failure, possibly contributing to immunodeficiency and HIV-1 replication in these patients.

Hydroxymethylglutaryl coenzyme a reductase inhibitors down-regulate chemokines and chemokine receptors in patients with coronary artery disease

OBJECTIVES

We sought to investigate whether the activation of the chemokine network observed in patients with coronary artery disease (CAD) could be modified by treatment with 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins).

BACKGROUND

Chemokines and chemokine receptors are important mediators in atherogenesis, and we hypothesized that the statins could affect the chemokine network in CAD.

METHODS

Thirty CAD patients without previous statin therapy were randomized to receive atorvastatin (80 mg/day, n = 15) or simvastatin (20 mg/day, n = 15). Peripheral blood mononuclear cells (PBMCs) and plasma were obtained at baseline and after six months of statin therapy. Messenger ribonucleic acid (mRNA) expression of chemokines and chemokine receptors in PBMCs was analyzed by ribonuclease protection assay and real-time reverse-transcription polymerase chain reaction. Chemokines were also examined in the supernatants from unstimulated and lipopolysaccharide-stimulated PBMCs (and in plasma).

RESULTS

Our main findings were: 1) gene expression of several chemokines (i.e., macrophage inflammatory protein [MIP]-1alpha, MIP-1beta, and interleukin [IL]-8) and chemokine receptors (i.e., CC chemokine receptor [CCR]1, CCR2, CCR4, and CCR5) was markedly increased among CAD patients compared with healthy control subjects; 2) treatment with atorvastatin and simvastatin markedly reduced the mRNA levels of some of these chemokines (i.e., MIP-1alpha, MIP-1beta, IL-8) and receptors (i.e., CCR1 and CCR2), with the most pronounced effect in the atorvastatin group; and 3) statin therapy reduced the spontaneous release of IL-8 and MIP-1alpha from PBMCs in CAD patients.

CONCLUSIONS

This study demonstrates a down-regulatory effect of statins on the chemokine network in CAD patients, possibly contributing to the beneficial effects of statins in this disorder.

Raised serum levels of soluble CD40 ligand in patients with familial hypercholesterolemia: downregulatory effect of statin therapy

OBJECTIVES

In the present study, we investigated the effects of statins on serum levels of soluble CD40 ligand (sCD40L) in patients with familial hypercholesterolemia (FH).

BACKGROUND

Atherosclerotic disease seems to involve inflammatory and immunologic mechanisms, and sCD40L has recently been identified as one of the key players in the atherosclerotic process. HMG-Co A reductase inhibitors, statins, have been recognized as immunomodulators and reduce cardiovascular events and mortality, but the effects of statins on sCD40L has not been clarified.

METHODS

In a randomized, double-blind, clinical trial, as part of the Atorvastatin versus Simvastatin on Atherosclerosis Progression (ASAP) trial, 110 patients with FH were given atorvastatin 80 mg/daily (n = 57) or simvastatin 40 mg/daily (n = 53) for two years.

RESULTS

Our main findings were: 1) at baseline patients with FH had significantly higher (approximately 27-fold) serum levels of sCD40L than healthy controls; 2) statin therapy markedly decreased serum levels of sCD40L (approximately 40% reduction); 3) this decrease in sCD40L was found during both "aggressive" (i.e., atorvastatin) and "conventional" (i.e., simvastatin) statin therapy and was not correlated with the degree of reduction in cholesterol levels.

CONCLUSIONS

Our findings may suggest enhanced CD40L-CD40 interaction in FH and that this inflammatory response may be downregulated by statins.

Inflammatory imbalance between IL-10 and TNFalpha in unstable angina potential plaque stabilizing effects of IL-10

BACKGROUND

The pathogenesis of atherosclerosis and acute coronary syndromes involves inflammation and immunological mechanisms. We hypothesized that patients with unstable angina may have an imbalance between inflammatory and anti-inflammatory cytokines.

DESIGN

Plasma levels of tumour necrosis factor (TNF)alpha and interleukin (IL)-10 were analyzed in 44 patients with stable angina, 29 patients with unstable angina and 20 controls. mRNA levels of these cytokines were analyzed in peripheral blood mononuclear cells (PBMC). We also studied the in vitro effects of IL-10 in PBMC from unstable angina patients.

RESULTS

Our main findings were: (1) the angina patients and particularly those with unstable disease had significantly raised TNFalpha in comparison with the controls, both at the protein and mRNA level; (2) in contrast, the levels of IL-10 were not different in the angina patients in comparison with the healthy controls, resulting in a markedly enhanced TNFalpha:IL-10 ratio, particularly in the unstable angina patients; (3) while exogenously added IL-10 markedly inhibited the release of TNFalpha, IL-8 and tissue factor as well as impairing the gelatinolytic activity and mRNA production of matrix metalloproteinase-9, it enhanced the tissue inhibitor of this metalloproteinase (i.e. TIMP-1) in PBMC from the unstable angina patients.

CONCLUSION

Patients with unstable angina appear to have an imbalance between TNFalpha and IL-10, possibly favouring inflammatory net effects. IL-10 may have beneficial effects on mechanisms that are important in plaque rupture and thrombus formation.

Stromal cell-derived factor-1alpha in unstable angina: potential antiinflammatory and matrix-stabilizing effects

BACKGROUND

Chemokines play a pathogenic role in atherogenesis and plaque destabilization by activating and directing leukocytes into the atherosclerotic plaque. However, stromal cell-derived factor (SDF)-1 was recently found to have antiinflammatory effects, and we hypothesized that this chemokine could play a beneficial role in coronary artery disease.

METHODS AND RESULTS

Plasma levels of SDF-1alpha were significantly decreased in patients with stable (n=30) and unstable angina (n=30) compared with healthy control subjects (n=20), particularly in those with unstable disease. By flow cytometry and RNase protection assay, we found decreased surface expression but increased gene expression of the SDF-1alpha receptor CXCR-4 in peripheral blood mononuclear cells (PBMC) from patients with stable angina and patients with unstable angina. In vitro, SDF-1alpha (500 ng/mL) reduced both unstimulated and endotoxin/mitogen-stimulated mRNA and protein levels of monocyte chemoattractant protein-1, interleukin-8, matrix metalloproteinase-9, and tissue factor while increasing tissue inhibitor of metalloproteinases-1 in PBMC from patients with unstable angina. The SDF-1alpha-mediated suppression of monocyte chemoattractant protein-1 and interleukin-8 appears to involve cAMP/protein kinase A type I-dependent pathways. Finally, although SDF-1alpha suppressed the spontaneous release of these inflammatory mediators in unstable angina, enhancing effects were seen in unstimulated PBMC from healthy control subjects, possibly reflecting that PBMC in unstable angina are preactivated in vivo.

CONCLUSIONS

In contrast to several other chemokines, our findings suggest that SDF-1alpha, at least in high concentrations, may mediate antiinflammatory and matrix-stabilizing effects in unstable angina. These effects may promote plaque stabilization, and therapeutic intervention that enhances SDF-1alpha activity could potentially be beneficial in acute coronary syndromes.