CRP, interleukin-6, secretory phospholipase A2 group IIA, and intercellular adhesion molecule-1 during the early phase of acute coronary syndromes and long-term follow-up

Mann T, Bastard K, F. Scott K, Church WB. Structural and Functional Aspects of Targeting the Secreted Human Group IIA Phospholipase A2

Human group IIA secretory phospholipase A₂ (hGIIA) promotes the proliferation of cancer cells, making it a compelling therapeutic target, but it is also significant in other inflammatory conditions. Consequently, suitable inhibitors of hGIIA have always been sought. The activation of phospholipases A₂ and the catalysis of glycerophospholipid substrates generally leads to the release of fatty acids such as arachidonic acid (AA) and lysophospholipid, which are then converted to mediator compounds, including prostaglandins, leukotrienes, and the platelet-activating factor. However, this ability of hGIIA to provide AA is not a complete explanation of its biological role in inflammation, as it has now been shown that it also exerts proinflammatory effects by a catalysis-independent mechanism. This mechanism is likely to be highly dependent on key specific molecular interactions, and the full mechanistic descriptions of this remain elusive. The current candidates for the protein partners that may mediate this catalysis-independent mechanism are also introduced in this review. A key discovery has been that selective inhibition of the catalysis-independent activity of hGIIA is achieved with cyclised derivatives of a pentapeptide, FLSYK, derived from the primary sequence of hGIIA. The effects of hGIIA on cell function appear to vary depending on the pathology studied, and so its mechanism of action is complex and context-dependent. This review is comprehensive and covers the most recent developments in the understanding of the many facets of hGIIA function and inhibition and the insight they provide into their clinical application for disease treatment. A cyclic analogue of FLSYK, c2, the most potent analogue known, has now been taken into clinical trials targeting advanced prostate cancer.

Predictive Value of Blood Interleukin-6 Level in Patients with Acute Coronary Syndrome: A Meta-analysis

OBJECTIVE

Conflicting results have been reported on the association between blood level of interleukin-6 and adverse outcomes in patients with acute coronary syndrome (ACS). The current meta-analysis aimed to evaluate the predictive utility of elevated blood interleukin-6 level in patients with ACS.

METHODS

A systematically literature search was performed using PubMed and Embase databases up to December 31, 2019. Observational studies or post hoc analysis of randomized controlled trials investigating the values of blood interleukin-6 level for predicting major adverse cardiovascular events (MACE including death, re-infarction, revascularization, angina, heart failure, malignant arrhythmia, or stroke), all-cause mortality or cardiovascular mortality in ACS patients were eligible. The predictive values were summarized by pooling the multivariable-adjusted risk ratio (RR) and 95% confidence intervals (CI) for the highest versus lowest category of interleukin-6 level.

RESULTS

Thirteen studies enrolling 30,289 patients with ACS were included. When comparing the highest with lowest category of interleukin-6 level, the pooled RR was 1.29 (95% CI 1.12-1.48) for MACE, 1.50 (95% CI 1.35-1.67) for all-cause mortality, and 1.55 (95% CI 1.06-2.28) for cardiovascular mortality, respectively. Moreover, the predictive values of interleukin-6 level on MACE were consistently found in different study designs, subtypes of patients, sample sizes, follow-up duration, and cutoff value of interleukin-6 elevation subgroups.

CONCLUSION

Increased blood level of interleukin-6may be independently associated with higher risk of MACE, cardiovascular and all-cause mortality in patients with ACS. Measurement of blood interleukin-6 level has potential to improve risk stratification of ACS.

An Updated Review of Pro- and Anti-Inflammatory Properties of Plasma Lysophosphatidylcholines in the Vascular System

Lysophosphatidylcholines are a group of bioactive lipids heavily investigated in the context of inflammation and atherosclerosis development. While present in plasma during physiological conditions, their concentration can drastically increase in certain inflammatory states. Lysophosphatidylcholines are widely regarded as potent pro-inflammatory and deleterious mediators, but an increasing number of more recent studies show multiple beneficial properties under various pathological conditions. Many of the discrepancies in the published studies are due to the investigation of different species or mixtures of lysophatidylcholines and the use of supra-physiological concentrations in the absence of serum or other carrier proteins. Furthermore, interpretation of the results is complicated by the rapid metabolism of lysophosphatidylcholine (LPC) in cells and tissues to pro-inflammatory lysophosphatidic acid. Interestingly, most of the recent studies, in contrast to older studies, found lower LPC plasma levels associated with unfavorable disease outcomes. Being the most abundant lysophospholipid in plasma, it is of utmost importance to understand its physiological functions and shed light on the discordant literature connected to its research. LPCs should be recognized as important homeostatic mediators involved in all stages of vascular inflammation. In this review, we want to point out potential pro- and anti-inflammatory activities of lysophospholipids in the vascular system and highlight recent discoveries about the effect of lysophosphatidylcholines on immune cells at the endothelial vascular interface. We will also look at their potential clinical application as biomarkers.

Identification of blood cell transcriptome-based biomarkers in adulthood predictive of increased risk to develop metabolic disorders using early life intervention rat models

Calorie restriction during gestation in rats has long-lasting adverse effects in the offspring. It induces metabolic syndrome-related alterations, which are partially reversed by leptin supplementation during lactation. We employed these conditions to identify transcript-based nutrient sensitive biomarkers in peripheral blood mononuclear cells (PBMCs) predictive of later adverse metabolic health. The best candidate was validated in humans. Transcriptome analysis of PBMCs from adult male Wistar rats of three experimental groups was performed: offspring of control dams (CON), and offspring of 20% calorie-restricted dams during gestation without (CR) and with leptin supplementation throughout lactation (CR-LEP). The expression of 401 genes was affected by gestational calorie restriction and reversed by leptin. The changes preceded metabolic syndrome-related phenotypic alterations. Of these genes, Npc1 mRNA levels were lower in CR vs CON, and normalized to CON in CR-LEP. In humans, NPC1 mRNA levels in peripheral blood cells (PBCs) were decreased in subjects with mildly impaired metabolic health compared to healthy subjects. Therefore, a set of potential transcript-based biomarkers indicative of a predisposition to metabolic syndrome-related alterations were identified, including NPC1, which was validated in humans. Low NPC1 transcript levels in PBCs are a candidate biomarker of increased risk for impaired metabolic health in humans.

Interleukin-6 and adhesion molecules VCAM-1 and ICAM-1 as biomarkers of post-acute myocardial infarction heart failure

Acute coronary syndromes are associated with a high prevalence of complications including heart failure (HF). The aim of this study was to investigate the association of novel biomarkers with the occurrence of post-acute myocardial infarction (AMI) HF. A prospective study was conducted with patients admitted to the emergency department with ST-segment elevation myocardial infarction (STEMI). Blood and urine samples were collected for analysis of traditional and novel biomarkers, including interleukin-6, vascular cell adhesion molecule 1 (VCAM-1), and intercellular adhesion molecule-1 (ICAM-1). We compared the levels of these biomarkers between patients with and without post-STEMI HF. A total of 48 patients were assessed, with a prevalence of males. Fifteen patients (31.2%) had post-STEMI HF. Patients with HF had higher mean values of IL-6, VCAM-1, and ICAM-1 compared to those who did not develop HF (57.06 vs 14.03 pg/mL, P=0.001; 1719.58 vs 1304.34 ng/mL, P=0.001; and 1594.20 vs 1158.74 ng/mL, P<0.001, respectively). The three biomarkers were shown to be good predictors of post-STEMI HF (IL-6: AUC 0.786, P=0.002; VCAM-1: AUC 0.797, P=0.001; and ICAM-1: AUC 0.825, P<0.0001), with the respective cutoff points being calculated based on the best sensitivity and specificity indexes (IL-6: 8.67 pg/mL; VCAM-1: 1501.42 ng/mL; and ICAM-1: 1262.38 ng/mL). Of the three biomarkers, only VCAM-1 and ICAM-1 had a direct linear association between them (r=0.470, P<0.0001). IL-6, VCAM-1, and ICAM-1 were associated with the development of new post-AMI HF symptoms, but only VCAM-1 and ICAM-1 correlated with each other, possibly because they have the same pathophysiological mechanism of action.

Associations between IL-6 and Echo-Parameters in Patients with Early Onset Coronary Artery Disease

BACKGROUND

Over the last two decades, many studies have investigated the association between interleukin 6 (IL-6) and pathogenesis and progression of coronary artery disease (CAD). Patients with CAD manifested at a young age are a particularly interesting group. They differ from older patients, not only in terms of the severity of coronary artery atherosclerosis, but also risk factor profiles, short- and long-term prognosis after myocardial infarction (MI). The role of IL-6 in younger patients with CAD is less well-known. Therefore, our study aimed to analyze the relationship between IL-6 level and other inflammations, atherosclerosis, and cardiac function parameters in early onset CAD patients.

METHODS

The study covered 100 patients with early onset CAD and a group of 50 healthy participants. Plasma levels of IL-6 and basic biochemical parameters, anthropometric, echocardiographic, and arteries Doppler ultrasound measurements were performed.

RESULTS

We did not observe a significant difference in IL-6 concentration in plasma between patients with early onset CAD and a control group, but IL-6 level was negatively correlated with echocardiographic measurements of ascending aorta diameter, left ventricular shortening fraction, and right ventricular end-diastolic diameter in our patients.

CONCLUSIONS

In patients with early onset CAD, plasma IL-6 level is associated with other inflammation parameters and with cardiac function, potentially contributing to right ventricular remodeling and left ventricular systolic dysfunction. This suggests possible prognostic benefits of long-time observation of IL-6 level after the acute coronary syndrome.

Mendelian Randomization Studies Promise to Shorten the Journey to FDA Approval

There has been a dearth of new drugs approved for cardiovascular disorders. The cost is prohibitive, averaging to $2.5 billion, and requiring 12.5 years. This is in large part due to the high failure rate, with only 5% approval by the Food and Drug Administration. Despite preclinical studies showing potential safety and efficacy, most fail when they go to clinical trials phase I to III. One cause for failure is the drug target, often discovered to be a biomarker rather than causative for the disease. Mendelian randomization (MR) studies would determine whether the drug target is causative and could save millions of dollars and time, and prevent unnecessary exposure to adverse drug effects. This was demonstrated in 3 clinical trials that were negative with 2 drugs, veraspladib and darapladib. MR studies during the trials showed the targets of secretory and lipoprotein-associated phospholipids A2 are not causative for coronary artery disease and predicted negative results. The requirement for MR studies is a genetic risk variant with altered function, randomized at conception that remains fixed throughout one’s lifetime. It is not confounded by dietary, lifestyle, or socioeconomic factors. It is more sensitive than randomized controlled trials because exposure to the risk factor is fixed for a lifetime. MR studies showed plasma high-density lipoprotein cholesterol is not a causative target of coronary artery disease, and neither is uric acid, C-reactive protein, and others. MR studies are highly sensitive in determining whether drug targets are causative, and are relatively easy, inexpensive, and not time consuming. It is recommended that drug targets undergo MR studies before proceeding to randomized controlled trials.

Molecular dynamics simulations reveal structural insights into inhibitor binding modes and functionality in human Group IIA phospholipase A2

Human Group IIA phospholipase A₂ (hGIIA) promotes inflammation in immune-mediated pathologies by regulating the arachidonic acid pathway through both catalysis-dependent and -independent mechanisms. The hGIIA crystal structure, both alone and inhibitor-bound, together with structures of closely related snake-venom-derived secreted phospholipase enzymes has been well described. However, differentiation of biological and nonbiological contacts and the relevance of structures determined from snake venom enzymes to human enzymes are not clear. We employed molecular dynamics (MD) and docking approaches to understand the binding of inhibitors that selectively or nonselectively block the catalysis-independent mechanism of hGIIA. Our results indicate that hGIIA behaves as a monomer in the solution environment rather than a dimer arrangement that is in the asymmetric unit of some crystal structures. The binding mode of a nonselective inhibitor, KH064, was validated by a combination of the experimental electron density and MD simulations. The binding mode of the selective pentapeptide inhibitor FLSYK to hGIIA was stipulated to be different to that of the snake venom phospholipases A₂ of Daboia russelli pulchella (svPLA₂ ). Our data suggest that the application of MD approaches to crystal structure data is beneficial in evaluating the robustness of conclusions drawn based on crystal structure data alone. Proteins 2017; 85:827-842. © 2016 Wiley Periodicals, Inc.

Acute coronary syndrome-associated depression: the salience of a sickness response analogy?

Depression emerging in conjunction with acute coronary syndrome (ACS) is thought to constitute a distinct high-risk phenotype with inflammatory determinants. This review critically examines the notion put forward in the literature that ACS-associated depression constitutes a meaningful subtype that is qualitatively different from depressive syndromes observed in psychiatric patients; and evaluates the salience of an analogy to the acute sickness response to infection or injury as an explanatory model. Specific features differentiating ACS-associated depression from other phenotypes are discussed, including differences in depression symptom profiles, timing of the depressive episode in relation to ACS, severity of the cardiac event, and associated immune activation. While an acute sickness response analogy offers a plausible conceptual framework, concrete evidence is lacking for inflammatory activity as the triggering mechanism. It is likely that ACS-associated depression encompasses several causative scenarios.

Deciphering the Causal Role of sPLA2s and Lp-PLA2 in Coronary Heart Disease

Over the last 10 to 15 years, animal and human observational studies have identified elevated levels of both proinflammatory secretory phospholipase A2-IIA and lipoprotein-associated phospholipase A2 as potential risk factors for coronary heart disease. However, Mendelian randomization, a genetic tool to test causality of a biomarker, and phase III randomized controlled trials of inhibitors of theses enzymes (varespladib and darapladib) converged to indicate that elevated levels are unlikely to be themselves causal of coronary heart disease and that inhibition had little or no clinical utility. The concordance of findings from Mendelian randomization and clinical trials suggests that for these 2 drugs, and for other novel biomarkers in future, validation of potential therapeutic targets by genetic studies (such as Mendelian randomization) before embarking on costly phase III randomized controlled trials could increase efficiency and offset the high risk of drug development, thereby facilitating discovery of new therapeutics and mitigating against the exuberant costs of drug development.

Inflammatory markers in ST-elevation acute myocardial infarction

After acute myocardial infarction, ventricular remodeling is characterized by changes at the molecular, structural, geometrical and functional level that determine progression to heart failure. Inflammation plays a key role in wound healing and scar formation, affecting ventricular remodeling. Several, rather different, components of the inflammatory response were studied as biomarkers in ST-elevation acute myocardial infarction. Widely available and inexpensive tests, such as leukocyte count at admission, as well as more sophisticated immunoassays provide powerful predictors of adverse outcome in patients with ST-elevation acute myocardial infarction. We review the value of inflammatory markers in ST-elevation acute myocardial infarction and their association with ventricular remodeling, heart failure and sudden death. In conclusion, the use of these biomarkers may identify subjects at greater risk of adverse events and perhaps provide an insight into the mechanisms of disease progression.

Early inflammatory cytokine response: a direct comparison between spontaneous coronary plaque destabilization vs angioplasty induced

AIM

To compare inflammatory response accompanying acute coronary syndrome (ACS) with that following coronary plaque rupture caused by coronary angioplasty (PCI).

METHODS

Twenty-seven consecutive subjects with either ACS or treated with PCI in the subacute phase of ACS underwent serial evaluation of circulating interleukin (IL)-2, IL-8, IL-10, interferon (IFN)-γ and tumor-necrosis-factor (TNF)-α levels. Blood samples were drawn immediately before angioplasty (T0) in the PCI group or at admission in the ACS group, 12 h (T1) and 24 h later (T2).

RESULTS

Differences between cytokine levels were substantially not statistically significant when comparing PCI, non-ST-elevation-ACS, and ST-elevation-ACS groups, especially 24 h after plaque rupture (T2, Type-II error 85-94%).

CONCLUSIONS

Inflammatory activation during the first 24 h of ACS or after PCI is comparable, regardless of myocardial damage in terms of troponin levels. Coronary plaque rupture may be presumed as being the main responsible for increased circulating cytokine levels in this early phase.

Risk assessment of post-infarction heart failure. Systematic review on the role of emerging biomarkers

The prognostic significance of cardiospecific troponins and natriuretic peptides in patients with myocardial ischemia is well established, and their measurement is now endorsed by the most important guidelines and recommendations for diagnosis and management of heart failure (HF). Additional biomarkers have also been investigated to support clinical judgment and diagnostic imaging in the stratification of risk of cardiac dysfunction in patients with myocardial infarction (MI). We have performed a systematic analysis of the current scientific literature regarding the most important biomarkers of HF, selecting all prospective studies with adequate sample size (i.e. >100 patients) that have assessed, during the early phase of myocardial ischemia, the prognostic value of emergent biomarkers for new-onset HF or deterioration of cardiac function in patients with MI. This analysis has provided some good evidence suggesting that, in most cases, the use of diagnostic biomarkers of cardiac dysfunction does not translate into efficient risk prediction of HF. However, some notable exceptions were found, including biomarkers of cardiac fibrosis (especially galectin-3), growth differentiation factor-15 (GDF-15), osteoprotegerin, C-reactive protein (CRP), and red blood cell distribution width (RDW). Nevertheless, future studies with well-defined characteristics including the use of larger sample sizes, standardized end points, and replication populations, along with benchmark analyses against other consolidated biomarkers (i.e. cardiospecific troponins and natriuretic peptides), should be planned. Such evaluations will help to establish whether an integrated approach including biomarkers of different pathogenetic pathways - for example, apoptosis, stress of cardiomyocytes, cardiac fibrosis, inflammation, and extra-cardiac involvement - may be cost effective for identifying patients at increased risk of developing HF, and who, therefore, may benefit from a tailored therapeutic strategy.

IL-6 signalling in patients with acute ST-elevation myocardial infarction

Cytokines of the IL-6 family have been related to infarct size and prognosis in patients with myocardial infarction. The aims of the present study were to elucidate possible associations between myocardial necrosis and left ventricular impairment and members of the IL-6 transsignalling system including soluble (s) IL-6R and (s) glycoprotein 130 (sgp130) in patients with ST-elevation myocardial infarction (STEMI) treated with primary PCI. In blood samples from 1028 STEMI patients, collected in-hosptial, we found significant correlations between peak TnT and IL-6 and CRP (p < 0.001, all) and between IL-6 and CRP and LV ejection fraction and NT-proBNP (p < 0.001, all). On the contrary, no significant associations were found between peak TnT and sgp130 or sIL-6R. Furthermore sgp130 was significantly elevated in diabetic patients and also associated with the glucometabolic state. In conclusion, circulating levels of IL-6 and CRP, but not the soluble forms of the receptor (sIL-6R) or the receptor signalling subunit (sgp130) were associated with the extent of myocardial necrosis. The biological importance of the IL-6/gp130-mediated signalling pathways in patients with acute myocardial infarction and dysglycemia should be further elucidated.

Effects of Wenxiao Decoction on the expression of interleukin-6, intercellular adhesion molecular-1 and monocyte chemoattractant protein-1 in experimental atherosclerotic rabbits

OBJECTIVE

To observe the effects of different doses of Wenxiao Decoction on the expression of interleukin-6 (IL-6), intercellular adhesion molecule-1 (ICAM-1), and monocyte chemoattractant protein-1 (MCP-1) in experimental atherosclerotic rabbits and to explore the mechanism by which it alleviates atherosclerosis.

METHODS

Sixty New Zealand rabbits were randomly divided into six groups: a blank group, a model group, a Simvastatin group, and high-, medium-, and low-dosage Wenxiao Decoction groups. Except for those in the blank group, all rabbits were fed with a high-cholesterol diet. Carotid atherosclerosis was established by balloon-induced carotid artery endothelium injury in conjunction with the high-cholesterol diet. After 8 weeks, all animals were euthanized to evaluate levels of IL-6 and ICAM-1 expressions (by enzyme linked immunosorbent assay) and of MCP-1 (by immunohistochemistry staining).

RESULTS

The expressions of IL-6, ICAM-1, and MCP-1 were significantly increased in all groups except the blank group (P<0.05). However, the rabbits in the Wenxiao Decoction groups and the Simvastatin group showed significantly lower levels of IL-6, ICAM-1, and MCP-1 expression than those in the model group (P<0.05). The expressions of IL-6, ICAM-1, and MCP-1 in the highdosage Wenxiao Decoction group and the Simvastatin group were lower than those in the low-dosage Wenxiao Decoction group (P<0.05). The expression of MCP-1 in medium-dosage Wenxiao Decoction group was lower than that in the low-dosage group (P<0.05).

CONCLUSIONS

High, medium, and low doses of Wenxiao Decoction can inhibit the expressions of IL-6, ICAM-1, and MCP-1, which may prevent and stabilize atherosclerotic plaques. There may be a direct relationship between dosage and therapeutic efficacy of Wenxiao Decoction.

Effects of Wenxiao II decoction on the expression of MCP-1 and VCAM-1 in atherosclerotic rabbits

OBJECTIVE

To observe the effects of different doses of wenxiao II decoction on the expression of monocyte chemoattractant protein-1 (MCP-1) and vascular cell adhesion molecule-1 (VCAM-1) in an experimental model of atherosclerosis in rabbits and to explore the mechanism by which it alleviates atherosclerosis.

METHODS

Sixty 3-4 month-old New Zealand rabbits of both sexes were randomly divided into six groups: simvastain; model; blank; and high-dose, mid-dose, and low-dose wenxiao II decoction groups. Except for those in the blank group, all rabbits were fed a high-cholesterol diet. Carotid atherosclerosis was established by balloon-induced injury to the endothelium of the carotid artery in conjunction with consumption of a high-cholesterol diet. After 8 weeks, all rabbits were killed to evaluate the expression of MCP-1 and VCAM-1 by immunohistochemical staining.

RESULTS

Expressions of MCP-1 and VCAM-1 were significantly decreased in all groups except the blank group compared with the model group (P < 0.05). When compared with the simvastain group only variation of MCP-1 expression in low-dose group was not appreciable, and the differences were indistinct (P < 0.05). When comparing among wenxiao II decoction groups, MCP-1 expression in the mid- and high-dose groups was significantly lower than that seen in the low-dose group (P< 0.01), but there were no differences among three dosage groups with respect to VCAM-1 expression (P > 0.05).

CONCLUSION

These data suggested that high, mid, and low doses of Wenxiao II Decoction can inhibit the expression of MCP-1 and VCAM-1, which may prevent the formation of or stabilize atherosclerotic plaques. There may be a direct relationship between the dosage of wenxiao II decoction and its therapeutic efficacy.

IgM-phosphorylcholine autoantibodies and outcome in acute coronary syndromes

BACKGROUND

Antibodies against proinflammatory phosphorylcholine (anti-PC) seem to be protective and reduce morbidity. We sought to determine whether low levels of immunoglobulin-M (IgM) autoantibodies against PC add prognostic information in acute coronary syndromes (ACS).

METHODS

IgM anti-PC titers were measured in serum obtained within 24h of admission from 1185 ACS patients (median age 66 years, 30% women). We evaluated major acute cardiovascular events (MACE) and all-cause mortality short--(6 months), intermediate--(18 months) and long--(72 months) terms.

RESULTS

Low anti-PC titers were associated with MACE and all-cause mortality at all follow-up times. After adjusting for clinical variables, plasma troponin-I, proBNP and CRP levels, associations remained at all times with MACE, short and intermediate terms also with all-cause mortality. With anti-PC titers below median, adjusted hazard ratios at 18months were for MACE 1.79 (95% confidence interval [CI]: 1.31 to 2.44; p=0.0002) and for all-cause mortality 2.28 (95% CI: 1.32 to 3.92; p=0.003). Anti-PC and plasma CRP were unrelated and added to risk prediction.

CONCLUSIONS

Serum IgM anti-PC titers provide prognostic information above traditional risk factors in ACS. The ease of measurement and potential therapeutic perspective indicate that it may be a valuable novel biomarker in ACS.

Established and novel biomarkers in ST-elevation myocardial infarction

Cardiac biomarkers assist in the diagnosis of and risk stratification in acute coronary syndromes. In ST-elevation myocardial infarction (STEMI), rapid diagnosis and initiation of reperfusion via primary percutaneous coronary intervention or fibrinolysis is often based on the clinical history and presenting ECG, but measurement of biomarkers in the early and/or late phases of STEMI may allow the selection of patients who are at increased or decreased risk of subsequent complications. Although the measurement of only three biomarkers (troponin, natriuretic peptides and C-reactive protein) are currently included in practice guidelines, more than 20 other novel cardiac biomarkers have been proposed to provide improved risk stratification after a STEMI.

Anti-inflammatory therapeutics for the treatment of atherosclerosis

Atherosclerosis is the primary cause of heart disease and stroke and is thus the underlying pathology of the leading causes of death in the western world. Although risk can be reduced by lowering lipid levels, the equally important contribution of inflammation to the development of cardiovascular disease is not adequately addressed by existing therapies. Here, we summarize the evidence supporting a role for inflammation in the pathogenesis of atherosclerosis, discuss agents that are currently in the clinic and provide a perspective on the challenges faced in the development of drugs that target vascular inflammation.

Adhesion molecules and C-reactive protein are associated to adverse events in angina pectoris

OBJECTIVES

To examine the prognostic value of soluble cellular adhesion molecules (CAMs) and highly sensitive C reactive protein (hsCRP) on long-term outcome for patients with stable angina pectoris (SAP).

DESIGN

In a prospective study, 291 patients referred for coronary angiography due to clinically suspected SAP had serum level of soluble intercellular adhesion molecule-1 (sICAM-1), vascular adhesion molecule-1 (sVCAM-1), sP-selectin and hsCRP determined at baseline. The primary outcome was predefined as death from any cause, myocardial infarction or stroke during a mean follow-up of 7.1 years.

RESULTS

Thirty four patients experienced the primary outcome. Hazard ratios and 95% confidence intervals for the primary outcome were: sVCAM-1: 2.4 [1.1-4.9], sICAM-1: 3.3 [1.5-7.2], sP-selectin: 1.2 [0.6-2.6] and hs-CRP: 3.1 [1.5-6.3], when comparing patients in the 4th quartile with those in lower quartiles in a multivariable model. Higher risk of adverse outcome was observed in patients having levels of both hsCRP and sICAM-1 (HR 4.7 [1.7-9.9]) or hsCRP and sVCAM-1 (HR 4.2 [1.7-9.9]) in the 4th quartile.

CONCLUSIONS

sVCAM-1, sICAM-1 and hsCRP were significantly associated with long term outcomes of patients with SAP beyond the risk associated with traditional risk factors. Risk predictions were improved when combining information about sCAMs and hsCRP.

Changes in inflammatory biomarkers in patients treated with ticagrelor or clopidogrel

BACKGROUND

Inflammation is a key factor in the development of atherosclerotic disease and acute coronary syndromes (ACS). The P2Y(12) receptor antagonists ticagrelor (AZD6140) and clopidogrel may have anti-inflammatory effects. The objective of this analysis from the Dose Confirmation Study Assessing Anti-Platelet Effects of AZD6140 vs Clopidogrel in NSTEMI 2 (DISPERSE 2) trial was to compare ticagrelor and clopidogrel for effects on the inflammatory biomarkers C-reactive protein (CRP), interleukin 6 (IL-6), myeloperoxidase (MPO), and soluble CD40 ligand (sCD40L).

HYPOTHESIS

Ticagrelor inhibits the P2Y(12) receptor and inflammation to a greater extent than clopidogrel in nonST-segment elevation ACS (NSTE-ACS) patients.

METHODS

In a double-blind, double-dummy, multicenter trial, 990 patients who had been hospitalized within the previous 48 hours with NSTE-ACS were randomized to receive ticagrelor 90 mg twice daily, ticagrelor 180 mg twice daily, or clopidogrel 300 mg initially and then 75 mg once daily. Within the ticagrelor groups, patients were also randomized to receive or not receive a loading dose of ticagrelor 270 mg initially. All patients received standard treatment for ACS, which included 325 mg aspirin initially and 75 to 100 mg aspirin each day subsequently. Inflammatory biomarkers were measured at baseline, upon hospital discharge, and after 4 weeks.

RESULTS

Inflammatory biomarker measurements were not significantly different among treatment groups at baseline, discharge, and 4 weeks.

CONCLUSIONS

Ticagrelor and clopidogrel appeared not to differ in this study with respect to the inflammatory biomarkers CRP, IL-6, MPO, and sCD40L in patients with NSTE-ACS.

Metabolism and atherogenic disease association of lysophosphatidylcholine

Lysophosphatidylcholine (LPC) is a major plasma lipid that has been recognized as an important cell signalling molecule produced under physiological conditions by the action of phospholipase A(2) on phosphatidylcholine. LPC transports glycerophospholipid components such as fatty acids, phosphatidylglycerol and choline between tissues. LPC is a ligand for specific G protein-coupled signalling receptors and activates several second messengers. LPC is also a major phospholipid component of oxidized low-density lipoproteins (Ox-LDL) and is implicated as a critical factor in the atherogenic activity of Ox-LDL. Hence, LPC plays an important role in atherosclerosis and acute and chronic inflammation. In this review we focus in some detail on LPC function, biochemical pathways, sources and signal-transduction system. Moreover, we outline the detection of LPC by mass spectrometry which is currently the best method for accurate and simultaneous analysis of each individual LPC species and reveal the pathophysiological implication of LPC which makes it an interesting target for biomarker and drug development regarding atherosclerosis and cardiovascular disorders.

Serum level of soluble intercellular adhesion molecule-1 correlates with pulmonary arterial pressure in children with congenital heart disease

BACKGROUND

Endothelial activation and vascular inflammation are thought to be the mechanisms of pulmonary hypertension. Increased expression of the intercellular adhesion molecule (ICAM-1) and raised serum level of its soluble form (sICAM-1) are found in various conditions associated with endothelial activation.

METHODS

Serum samples from 31 children (14 boys and 17 girls; age, 4.9 +/- 4.6 years) with congenital heart disease (CHD) collected at the time of cardiac catheterization were analyzed for sICAM-1 level. Uni- and multivariable stepwise linear regression analyses were performed for the following variables against the sICAM-1 level: age, hemoglobin, serum creatinine, systemic arterial pressure (SAP), pulmonary arterial pressure (PAP), pulmonary blood flow (Qp) and resistance (Rp), systemic blood flow (Qs) and resistance (Rs), Qp/Qs, Rp/Rs, and pulmonary and systemic oxygen saturation.

RESULTS

The sICAM-1 levels in children who had CHD with and without pulmonary hypertension were 411 +/- 110 and 344 +/- 81 ng/ml, respectively (p = 0.11). In the univariable models, age, serum creatinine, systolic PAP, mean PAP, diastolic PAP, Rp, and Rp/Rs were significantly correlated with sICAM-1 level. In the multiple stepwise regression model, only mean PAP remained as an independent predictor of sICAM-1 level (r = 0.55; p = 0.002).

CONCLUSION

Children with CHD and pulmonary hypertension had a trend toward elevated sICAM-1 compared with CHD children who had no pulmonary hypertension. A linear correlation was found between mean pulmonary arterial pressure and sICAM-1 level.

Porphyromonas gingivalis fimbriae-dependent interleukin-6 autocrine regulation by increase of gp130 in endothelial cells

BACKGROUND AND OBJECTIVE

Local persistent infection by Porphyromonas gingivalis leads to inflammatory systemic diseases, such as atherosclerosis. We have reported previously that avirulent P. gingivalis fimbriae-dependent invasion into endothelial cells might be involved in progression of atherosclerosis. Although interleukin-6 (IL-6) regulates progression of atherosclerosis, little is known about the relationship of P. gingivalis fimbriae-dependent invasion to IL-6 regulation in endothelial cells.

MATERIAL AND METHODS

We examined the secretion of IL-6 and the expression of the IL-6 signal transducer gp130 in human umbilical vein endothelial cells (HUVEC) infected with the wild-type FDC381 strain of P. gingivalisand a fimbriae-deficient mutant (fimA) by enzyme-linked immunosorbent assay, quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) and flow cytometry (fluorescence-activated cell sorting, FACS) analysis.

RESULTS

Coculture of HUVEC with P. gingivalis resulted in increase of IL-6 secretion at 24 h postinfection. Interestingly, the increase was inhibited significantly in HUVEC infected with the P. gingivalis fimA mutant. In addition, the increase of IL-6 secretion induced by P. gingivalis infection was significantly impaired by the meiosis specific kinase 1 inhibitor, PD98059, or the nuclear factor kappaB inhibitor, Bay11-7082. Furthermore, we demonstrated that gp130 expression increased with P. gingivalis infection. Importantly, gp130 expression was significantly impaired by P gingivalis fimA mutant infection compared with wild-type P. gingivalis infection, as assessed by both quantitative RT-PCR and FACS analysis.

CONCLUSION

Our findings indicate that P. gingivalis fimbriae are important factors in the autocrine regulation of IL-6, by increasing gp130 in endothelial cells.

The value of biochemical markers for risk stratification prior to hospital admission in acute chest pain

We describe the use of biochemical markers in the pre-hospital setting with regard to diagnostic accuracy for the detection of an acute myocardial infarction (AMI) and for prognosis in connection with acute chest pain. The sensitivity has been reported to be limited; blood sampling occurs very early and often prior to the release of biochemical markers into the circulation. The specificity was in some studies also limited, but this is more difficult to explain. New biochemical markers like human heart fatty acid binding protein (H-FACB) have shown improved diagnostic accuracy, in the pre-hospital setting, in one small pilot study compared with traditional biochemical markers like troponins, creatine kinase (CK-MB) and myoglobin. However, in a recent small study, the sensitivity for troponin I (when a low decision limit for myocardial damage was used), when analysed prior to hospital admission, was reported to be very high. The latter data need to be confirmed in larger studies and various biochemical markers reflecting various pathophysiological aspects of the disease need to be tested before the analysis of any marker can be recommended for use in the pre-hospital setting of a suspected AMI.

Role of secretory phospholipases in atherogenesis

Elevated circulating levels of secretory phospholipase A(2) (sPLA(2)) are associated with atherosclerotic cardiovascular disease. sPLA(2) can contribute to atherogenesis by hydrolyzing phospholipids of circulating lipoproteins and lipoproteins entrapped in the arterial wall and/or in cells that reside in the intima and that participate in the inflammatory response to lipoprotein deposition. This article reviews differences and similarities between sPLA(2)-IIA, sPLA(2)-V, and sPLA(2)-X, all of which are members of this family of enzymes with reported potential proatherogenic features. Published data suggest that each of the enzymes has a distinct profile characterized by differences in tissue expression and localization, capacity to act on phospholipids of cell membranes and lipoproteins, and their interaction with arterial proteoglycans. In addition, the article discusses results from the authors' laboratory showing that diet-induced or gene-induced hyperlipidemia in mice enhances the expression of sPLA(2)-V in different tissues, but not sPLA(2)-IIA. Such differences indicate that these enzymes may have different roles in atherosclerotic cardiovascular disease through their distinct profiles.

Increased lipolysis by secretory phospholipase A(2) group V of lipoproteins in diabetic dyslipidaemia

BACKGROUND

Lipolysis of lipoproteins by secretory phospholipase A(2) group V (sPLA(2)-V) promotes inflammation, lipoprotein aggregation and foam cell formation--all considered as atherogenic mechanisms.

OBJECTIVE

In this study, we compared the susceptibility to sPLA(2)-V lipolysis of VLDL and LDL from individuals with type 2 diabetes and the metabolic syndrome (T2D-MetS) and from healthy controls. Design. VLDL and LDL were isolated from 38 T2D-MetS subjects and 38 controls, treated pair-wise. Extent of sPLA(2)-V lipolysis was measured as release of nonesterified free fatty acids (NEFA). In a subset of the subjects, lipoprotein composition was determined as a relationship between lipid and apolipoprotein components.

RESULTS

Mean paired increase in sPLA(2)-V lipolysis after 1 h for T2D-MetS versus control was 2.0 micromol NEFA l(-1) for VLDL (P = 0.004) and 0.75 micromol NEFA l(-1) for LDL (P = 0.001). There were also substantial differences in lipoprotein composition between the groups. T2D-MetS VLDL had higher triglyceride and cholesterol contents than control VLDL. T2D-MetS LDL was smaller and contained more triglycerides and less cholesterol than control LDL. Both VLDL and LDL from T2D-MetS subjects also contained more apolipoprotein CIII per particle.

CONCLUSION

VLDL and LDL from T2D-MetS individuals were more susceptible to sPLA(2)-V lipolysis than those from control individuals. This may result in elevated levels of NEFA and lysophosphatidylcholine, both in circulation and in LDL, possibly contributing to the elevated inflammatory state and increased risk of cardiovascular diseases seen in these individuals.

Release of protein as well as activity of MMP-9 from unstable atherosclerotic plaques during percutaneous coronary intervention

OBJECTIVES

Few studies have investigated the composition of unstable coronary plaques in vivo in humans. The aims of this study were to investigate if substances released from plaques during percutaneous coronary intervention (PCI) under distal protection could give information about plaque composition and also indicate possible biomarkers in plasma that may be used to identify patients at risk.

METHODS AND RESULTS

Twenty patients with acute coronary syndromes undergoing PCI with distal protection were included. Plasma samples were taken before, during, and after the PCI in the aortic root, locally in the culprit vessel and intravenously. Plasma was analysed for possible markers of plaque instability. During PCI, local increases were observed for matrix metalloproteinase 9 (MMP-9), protein (P < 0.001) as well as activity (P < 0.001), interleukin 6 (IL-6; P < 0.01) and oxidized low-density lipoprotein (oxLDL; P = 0.01) in the culprit coronary artery. A systemic inflammatory response was also seen with increased levels of IL-10, MMP-3, serum amyloid A and C-reactive protein, but with no increase in MMP-9.

CONCLUSIONS

Our study shows that local sampling of blood under distal protection may be used to analyse coronary plaques and to identify biomarkers for unstable plaques. Our results suggest that MMP-9 is a potential biomarker, and that IL-6, MMP9 and possibly oxLDL are released from plaques.

Inflammation and endothelial activation is evident at birth in offspring of mothers with type 1 diabetes

OBJECTIVE

Offspring of mothers with diabetes are at risk of obesity and glucose intolerance in later life. In adults, markers of subclinical inflammation (C-reactive protein [CRP] and interleukin [IL]-6) and endothelial activation (intracellular adhesion molecule [ICAM]-1) are associated with obesity and higher risk for incident type 2 diabetes. We examined whether these biomarkers were elevated at birth in offspring of type 1 diabetic mothers (OT1DM).

RESEARCH DESIGN AND METHODS

Umbilical cord plasma CRP, IL-6, and ICAM-1 were measured in 139 OT1DM and 48 control offspring, with analysis relative to fetal lipids and hormonal axes.

RESULTS

OT1DM had higher median (interquartile range) CRP (OT1DM 0.17 mg/l [0.13-0.22] vs. control subjects 0.14 mg/l [0.12-0.17], P < 0.001) and ICAM-1 (OT1DM 180 ng/ml [151-202] vs. control subjects 166 ng/ml [145-187], P = 0.047). IL-6 was not different after necessary adjustment for mode of delivery. Birth weight was unrelated to inflammatory indexes; however, leptin was correlated with CRP (control subjects r = 0.33, P = 0.02; OT1DM r = 0.41, P < 0.001) and with IL-6 (r = 0.23, P < 0.01) and ICAM-1 (r = 0.29, P < 0.001) in OT1DM. In OT1DM, CRP correlated with maternal glycemic control (A1C at 35-40 weeks; r = 0.28, P = 0.01). In multivariate analysis, leptin was a determinant of CRP (P < 0.001), ICAM-1 (P = 0.003), and IL-6 (P = 0.02) in OT1DM. Inflammatory measures demonstrated positive relationships with triglycerides in OT1DM (CRP, IL-6, and ICAM-1 P < 0.05) and control subjects (ICAM-1 P = 0.001).

CONCLUSIONS

Inflammatory markers are increased in OT1DM and are related to measures of fetal adiposity, particularly leptin, and maternal glycemia. Subclinical inflammation is a novel component of the diabetic intrauterine environment and should be considered a potential etiological mechanism for in utero programming of disease.

C-reactive protein, interleukin-6, secretory phospholipase A2 group IIA and intercellular adhesion molecule-1 in the prediction of late outcome events after acute coronary syndromes

OBJECTIVE

We investigated whether levels of C-reactive protein (CRP), interleukin-6 (IL-6), secretory phospholipase A(2) group IIA (sPLA(2)-IIA) and intercellular adhesion molecule-1 (ICAM-I) predict late outcomes in patients with acute coronary syndromes (ACS).

DESIGN

Prospective longitudinal study. CRP (mg L(-1)), IL-6 (pg mL(-1)), sPLA(2)-IIA (ng mL(-1)) and ICAM-1 (ng mL(-1)) were measured at days 1 (n = 757) and 4 (n = 533) after hospital admission for ACS. Their relations to mortality and rehospitalization for myocardial infarction (MI) and congestive heart failure (CHF) were determined.

SETTING

Coronary Care Unit at Sahlgrenska University Hospital, Gothenburg, Sweden.

SUBJECTS

Patients with ACS alive at day 30; median follow-up 75 months.

RESULTS

Survival was related to day 1 levels of all markers. After adjustment for confounders, CRP, IL-6 and ICAM-1, but not sPLA(2)-IIA, independently predicted mortality and rehospitalization for CHF. For CRP, the hazard ratio (HR) was 1.3 for mortality (95% confidence interval (CI): 1.1-1.5, P = 0.003) and 1.4 for CHF (95% CI: 1.1-1.9, P = 0.006). For IL-6, HR was 1.3 for mortality (95% CI: 1.1-1.6, P < 0.001) and 1.4 for CHF (95% CI: 1.1-1.8, P = 0.02). For ICAM-1, HR was 1.2 for mortality (95% CI: 1.0-1.4, P = 0.04) and 1.3 for CHF (95% CI: 1.0-1.7, P = 0.03). No marker predicted MI. Marker levels on day 4 provided no additional predictive value.

CONCLUSIONS

In patients with ACS, CRP, IL-6, sPLA(2)-IIA and ICAM-1 are associated with long-term mortality and CHF, but not reinfarction. CRP, IL-6 and ICAM-1 provide prognostic information beyond that obtained by clinical variables.

Inflammation, endothelial dysfunction and angiogenesis markers in chronic heart failure patients

This study was conducted to assess the relationship among circulating markers of inflammation, endothelial dysfunction and angiogenesis in 59 chronic heart failure (CHF) patients. Increased concentrations of C-reactive protein (CRP), tumour necrosis factor-alpha (TNF-alpha), von Willebrand factor (VWF) and fibrinogen are strongly implicated in the development of CHF. Increased vascular endothelium grow factor (VEGF) and decreased thrombospondin-1 (TSP-1) concentrations suggest a role of angiogenesis in the maintenance and repair of luminal endothelium in CHF. A relationship among markers of endothelial dysfunction (VWF) and inflammation (fibrinogen, CRP) and angiogenesis (VEGF, TSP-1) was found in CHF patients.

Prognostic significance of interleukin-6 measurement in the diagnosis of acute myocardial infarction in emergency department

BACKGROUND

Markers of inflammation may predict both coronary artery disease (CAD) and adverse outcomes in patients with known CAD. Here, we investigated the role of interleukin-6 (IL-6) in the "triage" and risk assessment of patients admitted to emergency department (ED).

METHODS

Serum IL-6 and high sensitivity C-reactive protein (hs-CRP) levels were prospectively evaluated in 88 patients with a history of precordial chest pain or shortness of breath of recent onset (<6 h).

RESULTS

Of the 88 patients, 21% were discharged from the ED with diagnosis of non-ischemic chest pain (NICP), 39% had a final diagnosis of unstable angina (UA) and 40% experienced an acute myocardial infarction (AMI). Median IL-6 (p<0.001) and hs-CRP (p<0.01) levels on admission were significantly increased in patients with AMI compared with patients with NICP or UA. IL-6 levels correlated with hs-CRP (p<0.01). Multivariate analyses including known risk factors showed that elevated creatine kinase-MB (p<0.05) and IL-6 levels (p<0.01) were independently associated with a final diagnosis of AMI. Elevated IL-6 levels significantly predicted the risk of AMI (OR=2.47, p=0.006) in chest pain-enzyme negative patients.

CONCLUSIONS

IL-6 may behave as an adjunctive diagnostic tool to assist in the risk assessment of enzyme-negative patients with precordial chest pain of recent onset.

Circulating secretory phospholipase A2 activity and risk of incident coronary events in healthy men and women: the EPIC-Norfolk study

OBJECTIVE

To assess the association between secretory phospholipase A2 (sPLA2) activity, which encompasses several types of sPLA2, and cardiovascular disease (CAD) in healthy individuals.

METHODS AND RESULTS

We investigated this association in a nested case-control study among the 25,663 participants in EPIC-Norfolk cohort. Cases (n=991) were subjects in whom CAD developed during the 6 years of mean follow-up. Controls (n=1806) matched by age, sex, and enrollment time remained free of any CAD during follow-up. The risk of incident CAD was associated with increasing quartiles of sPLA2 activity (P<0.001). After adjustment for risk factors, C-reactive protein and sPLA2 type IIA concentration, the odds ratios of incident CAD in the second, third, and fourth quartiles of sPLA2 activity were 1.41, 1.33, and 1.56 (P=0.003), compared with the lowest quartile. sPLA2 activity and CRP were poorly correlated (r=0.15), and their combined values were more informative for incident risk of CAD than either biomarker alone. Subjects in the highest quartiles of sPLA2 activity and CRP had an adjusted odds ratio of 2.89 (95% confidence interval, 1.78 to 4.68; P<0.001) for CAD compared with those with the lowest quartiles of both markers.

CONCLUSIONS

Measurement of serum sPLA2 activity provides additive prognostic value to traditional risk factors and CRP levels, and identifies a subgroup of individuals at high risk for incident CAD. Measurement of sPLA2 type II concentration had little added prognostic utility.

Secretory phospholipase A2 activity and release kinetics of vascular tissue remodelling biomarkers after coronary artery bypass grafting with and without cardiopulmonary bypass

BACKGROUND

Cardiopulmonary bypass (CPB) has long been recognised as a main cause of a postoperative complex systemic inflammatory response after coronary artery bypass grafting (CABG).

METHODS

We determined the kinetics of peripheral blood release of the novel inflammatory biomarkers secretory phospholipase A(2) (sPLA(2)), matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) during the first 6 days following surgery in 16 patients undergoing CABG with (on-pump, n=9) or without (off-pump, n=7) CPB. Kinetic curves for these markers were compared to those of the well-known inflammatory parameters C-reactive protein (CRP) and fibrinogen.

RESULTS

sPLA(2) activity exhibited a maximum value on day 2, then decreased until day 6 for both groups and in a similar manner as CRP levels. On the other hand, elevation of plasma levels of both MMP-9 and TIMP-1 occurred as early as on day 1 and remained at this level until day 6. No significant difference in kinetic characteristics (peak value, area under the curve, initial slope) between CABG with and without CPB was observed.

CONCLUSIONS

These data show that the off- and on-pump groups did not show significantly different kinetics for the releases of all biomarkers studied, including sPLA(2) and biomarkers of the MMP-TIMP network. The off-pump procedure may therefore lead to global surgical trauma as important as CPB in terms of the systemic inflammatory process and matrix proteolysis pathway activation.

Augmented levels of CD44 in macrophages from atherosclerotic subjects: a possible IL-6-CD44 feedback loop?

The cell-adhesion molecule CD44 likely participates in atherosclerosis development. We have shown previously that pro-inflammatory cytokines affect CD44 expression. Therefore, this work examined the role of elevated CD44 levels in human macrophages. Macrophages from human atherosclerotic subjects (n=15) showed elevated levels of CD44 transcript and protein (1.5-fold) compared to matched controls (n=15) (P=0.050 and 0.044, respectively). To test whether genetic factors influence CD44 expression, two single nucleotide polymorphisms in the CD44 gene were analyzed but these were not associated with coronary artery disease. We also examined the potential connection between plasma cytokine levels and CD44 expression. In atherosclerotic subjects, elevated CD44 expression correlates (P=0.012) with enhanced macrophage IL-6 secretion (3.13+/-2.5 pg/mL versus 0.32+/-0.16 pg/mL in controls, P=0.021). Additionally, CD44-deficient mice exhibit less circulating IL-6 than wild-type controls (9.8+/-0.7 pg/mL versus 14.3+/-0.7 pg/mL; P=0.032). Furthermore, IL-6 augments CD44 expression in primary human macrophages after 24 h (P=0.038) and 48 h (P=0.015). Taken together, our data show an IL-6-CD44 feedback loop in macrophages. Such a positive feedback loop may aggravate atherosclerosis development.