Redefining Risk in Acute Coronary Syndromes Using Molecular Medicine

HLA and killer cell immunoglobulin-like receptor (KIRs) genotyping in patients with acute ischemic stroke

INTRODUCTION

In humans, a major component of natural killer (NK) and T cell target recognition depends on the surveillance of human leukocyte antigen (HLA) class I molecules by killer immunoglobulin-like receptors (KIRs).

AIMS

To implement the knowledge about the immunological genetic background of acute ischemic stroke susceptibility in relation to the frequency of the KIR genes and HLA alleles.

METHODS

Subjects with acute ischemic stroke and subjects without stroke were genotyped for the presence of KIR genes and of the three major KIR ligand groups, HLA-C1, HLA-C2, and HLA-Bw4, both HLA-B and HLA-A loci.

RESULTS

Between November 2013 and February 2016, consecutive patients with acute ischemic stroke were recruited. As healthy controls, we enrolled subjects without acute ischemic stroke. Subjects with acute ischemic stroke in comparison with controls showed a higher frequency of 2DL3, 2DL5B, 2DS2, and 2DS4 KIR genes and a lower frequency of HLA-B-Bw4I alleles. Subjects without acute ischemic stroke showed a higher frequency of interaction between KIR 2DS2 and HLAC2. We also observed a higher frequency of 2DL3 and 2 DL4 KIR genes in subjects with atherosclerotic (LAAS) subtype. Multiple logistic regression analysis showed a protective effect towards stroke of HLA-B-Bw4I and interaction between KIR 2DL2 and HLAC1 and 2DS2-HLAC2 and a detrimental effect of 2DL2-HLA-C1_A interactions.

CONCLUSION

Our findings of a higher frequency of activating KIR genes seem to be consistent with findings previously reported patients with coronary syndrome. This higher frequency of "proinflammatory" genes in subjects with ischemic stroke could also explain the immunoinflammatory activation of the acute phase of stroke.

Association of serum microRNA-21 levels with Visfatin, inflammation, and acute coronary syndromes

MicroRNAs (miRNAs) are short non-coding RNAs that regulate gene expression. It seems that microRNA-21 (miR-21) and Visfatin, a novel adipocytokine, play roles in inflammation and atherosclerosis. The aim of this study was to investigate the association of miR-21 with Visfatin, inflammation, atherosclerosis and acute coronary syndrome (ACS). Based on coronary angiography and electrocardiogram (ECG), 53 patients with ACS and 52 patients with stable CAD were enrolled in this study. We assayed serum miR-21, Visfatin, and routine chemistries using quantitative reverse transcriptase polymerase chain reaction (QRT-PCR), enzyme-linked immunosorbent assay (ELISA) and automated analyzer, respectively. We used a regression analysis to describe the relationship between the variables. Serum miR-21 level in 2^-ΔCt value was significantly higher in ACS patients (10.52 ± 1.01-fold) than the stable CAD patients (4.4 ± 0.79-fold) (F = 4.59, p < 0.001). In addition, serum Visfatin was significantly higher in ACS patients (17.5 ± 0.61 ng/ml) than the stable CAD patients (12.7 ± 0.49 ng/ml) (F = 2.62, p < 0.001). Furthermore, the serum miR-21 level correlated positively with serum Visfatin level (r = 0.26, p = 0.008), hs-CRP (r = 0.29, p = 0.003), age (r = 0.21, p = 0.034) and negatively with HDL-cholesterol (r = -0.28, p = 0.004). We concluded that the increased serum miR-21 and Visfatin may be involved in the pathogenesis of ACS through promoting inflammation or may result from inflammatory responses to ACS. Furthermore, the potential role of miR-21 and Visfatin in plaque instability and inflammation warrants further investigations.

Effect of collection tube type and freeze-thaw cycles on myeloperoxidase concentrations in blood samples of acute coronary syndrome patients

Background Myeloperoxidase has shown potential as a marker for prognosis of coronary artery disease, but presently little is known about preanalytical handling of samples for quantifying myeloperoxidase. The present study was conducted to evaluate the effect of collection tube and freeze-thaw cycles on myeloperoxidase concentrations. Methods Acute coronary syndrome patients ( n = 88) were enrolled after obtaining written informed consent from coronary care unit of a tertiary care hospital (January 2012-June 2014). About 5 mL venous blood was collected from patients and divided into serum, lithium heparin, ethylenediaminetetraacetic acid and sodium citrate tubes. Except serum, all tubes were kept on ice immediately after collection. Samples were centrifuged at -4℃, separated immediately after centrifugation and stored at -40℃ until analysis. Myeloperoxidase was quantified by in-house and commercial assays and re-quantified after five freeze-thaw cycles. Results Myeloperoxidase concentrations, (serum samples) determined by commercial and in-house assays correlated well (r = 0.946) ( P < 0.001) and were higher in serum samples. Within plasma, myeloperoxidase concentrations were slightly higher in ethylenediaminetetraacetic acid (307.7 ± 52.1) and lower in lithium heparin (290.3 ± 49.2) and sodium citrate (221.4 ± 40.3) but not statistically significant. Correlation between myeloperoxidase concentrations (in-house enzyme-linked immunosorbent assay) after first cycle and fifth freeze-thaw cycle dropped to r = 0.448 ( P < 0.001). Conclusion Myeloperoxidase concentrations are comparable in three types of plasma tubes when samples are placed on ice immediately, centrifuged at low temperatures and separated immediately after centrifugation. Multiple freeze-thaw cycles have an effect on myeloperoxidase and should be avoided for quantifying myeloperoxidase.

Exercise-induced vasodilation in healthy males: A marker of reduced endothelial function

OBJECTIVES

Reduced arterial vasodilatatory capacity is a marker of coronary heart disease. The aim was to investigate if the difference between the vasodilatory response before and after exercise, as assessed by non-invasive methodology, is related to endothelial and inflammatory biomarkers.

DESIGN

Post-ischemic hyperemia after 5 min of arterial occlusion was examined before and after a bicycle test with strain-gauge plethysmography (measuring peak reactive hyperemia in the forearm) and peripheral arterial tonometry (PAT hyperemia ratio: measuring pulse waves in the index finger relative to the contra-lateral index finger) in 30 healthy males. A low PAT hyperemia ratio or a low peak reactive hyperemia reflects endothelial dysfunction. Inflammatory and endothelial biomarkers were assessed.

RESULTS

A low peak reactive hyperemia and a low PAT hyperemia ratio before the bicycle test was associated with a high percentage increase in peak reactive hyperemia after exercise (r = - 0.68, p < 0.001; r = - 0.35, p = 0.06, respectively). Asymmetric dimethylarginine and interleukin-10 were associated with the percentage increase in peak reactive hyperemia in multiple linear regression analyses (β: 165 (confidence interval [CI], 34-296), p = 0.02; β: 19 (CI, - 0.5-39), p = 0.06, respectively).

CONCLUSIONS

The difference in the vasodilatory response before and after exercise, as assessed by non-invasive methodology, is related to endothelial and inflammatory biomarkers in healthy males.

Assessment of mean platelet volume and soluble CD40 ligand levels in patients with non-dipper hypertension, dippers and normotensives

Abstract Objective: Patients with a lack of nocturnal decline in blood pressure (BP) are at an increased risk for cardiovascular events. Mean platelet volume (MPV) and soluble CD40 ligand (sCD40L) are accepted biomarkers of platelet activation and considered as a risk factor for cardiovascular disease. The aim of this study was to determine whether MPV and sCD40L levels are higher in non-dipper hypertensive (NDHT) patients than in dipper hypertensive (DHT) patients and healthy controls.

METHODS

124 consecutive patients were included to this study. Patients were divided into three groups: NDHT patient group [n = 43; mean age 51.8 ± 6.6; 31 males (72.1%)]; DHT patient group [n = 41; mean age 50.2 ± 7.3; 22 males (53.7%)]; and normotensive group [n = 40; mean age 49.9 ± 6.7; 22 males (55%)]. Physical examination, laboratory work-up and 24-h ABPM were performed for all participants.

RESULTS

The sCD40L and MPV levels were significantly higher in the NDHT group than in the DHT and normotensive groups (p < 0.05). In correlation analysis, MPV, 24-h systolic blood pressure (SBP), 24-h diastolic blood pressure (DBP), night-time SBP and night-time DBP were positively correlated with sCD40L.

CONCLUSION

Our study demonstrated that MPV and sCD40L levels were significantly higher in NDHT patients compared to DHT and normotensive patients. sCD40L levels were positively correlated with MPV, 24-h SBP, 24-h DBP, night-time SBP and night-time DBP.

Preparation, characterization and in vitro thrombolytic activity of a novel streptokinase foam

Vascular thrombosis is a potentially fatal disease. Thrombolysis represents an efficient therapeutic option, although it still presents intrinsic bleeding risks. In order to minimize this problem, intra-thrombus injections, alone or associated with some kind of mechanical thrombectomy, have been used. In this work, a new approach to thrombolysis is presented, where the preparation, characterization and in vitro thrombolytic activity of a novel streptokinase foam are reported. Foams were prepared by mixing albumin solution with CO2 at different volume ratios. Foam stability and apparent viscosity were the parameters used to characterize the foams. The volume ratio between CO2 and albumin solution that yielded the samples with the best properties was used to prepare the thrombolytic foams, where streptokinase was used as the thrombolytic agent. The thrombolytic effect of this foam was assessed in vitro by delivering it intra-thrombus and the results were compared with those of the foam without streptokinase as well as those of a regular streptokinase solution. Both foam stability and viscosity increased as the ratio of CO2:albumin solution increased and the 3:1 ratio was used to incorporate streptokinase. The in vitro thrombolytic activity study revealed that the streptokinase foam caused a 46.6 % of thrombus lysis after 30 min of experiment against 21 and 31 % of those of the foam without streptokinase and the regular streptokinase liquid solution, respectively. Thus, the use of CO2:albumin foam enhanced the in vitro thrombolytic effect of streptokinase, which indicates its potential as a novel vehicle for carrying and delivering streptokinase to targeted thrombi.

[Urgent percutaneous coronary intervention leads to a decrease in serum concentrations of soluble CD40 ligand]

BACKGROUND/AIM

Inflammation as a consequence of vascular injury after percutaneous coronary intervention (PCI) is a pathological substrate of restenosis and of its complications. The aim of the study was to examine perprocedural inflammatory response expressed by soluble CD40 ligand (sCD40L) and C-reactive protein (CRP) in patients treated with PCI and dual antiplatelet therapy.

METHODS

The experimental group included 52 patients (80.8% men, age 60 +/- 9 years) with angina pectoris treated by PCI (22 urgent PCI) with stent implantation, and dual antiplatelet therapy (tienopiridins and aspirin), according to the current recommendations for the execution of the intervention. The control group consisted of 8 patients (70.5% men, age 59 +/- 7 years) with angina pectoris, who had undergone coronarography taking aspirin 3 days prior to it. In all the patients 24 hours before and after the PCI concentrations of CRP and sCD40L in the blood were determined.

RESULTS

In the experimental group, the concentration of sCD40L was lower as compared to the control (p < 0.02). In 34 (65%) patients postprocedural decrease in sCD40L was recorded, in 18 (34.6%) of them increase, while in 50 (96%) patients there was a rise in CRP. The patients with postprocedural fall in sCD40L hod greater preprocedural concentration of sCD40L (p < 0.001), and less postprocedural concentration of sCD40L (p < 0.001), compared to the group with an increase in sCD40L after the PCI, while CRP levels between these groups were not statistically different. Patients treated with emergency PCI compared to elective patients had a postprocedural decrease in sCD40L (p = 0.02). Increase in the level of CRP was higher in the group with emergency PCI in relation to elective PCI (p < 0.01).

CONCLUSION

Emergency PCI procedures in the treatment of patients with unstable angina pectoris lead to a postprocedural fall in the serum concentration of sCD40L. Dual antiplate therapy with tienopiridins and aspirin inhibits the release of sCD40L. Regardless a clinical presentation of coronary disease PCI leads to an postprocedural increase in concentrations of CRP in the serum.

Increased expression and secretion of resistin in epicardial adipose tissue of patients with acute coronary syndrome

The purpose of this study was to test the hypothesis that specific epicardial adipose tissue (EAT) proinflammatory adipokines might be implicated in acute coronary syndrome (ACS). We compared expression and protein secretion of several EAT adipokines of male ACS with those of matched stable coronary artery disease (CAD) patients and controls with angiographically normal coronary arteries. The effect of supernatant of cultured EAT on endothelial cell permeability in vitro was also evaluated in the three study groups. EAT of ACS patients showed significantly higher gene expression and protein secretion of resistin than patients with stable CAD. Interleukin-6, plasminogen activator inhibitor-1, and monocyte chemoattractant protein-1 genes were also significantly overexpressed in ACS compared with the control group but not when compared with stable CAD. Immunofluorescence of EAT sections revealed a significantly greater number of CD68(+) cells in ACS patients than stable CAD and control groups. The permeability of endothelial cells in vitro was significantly increased after exposure to supernatant of cultured EAT from ACS, but not control or stable CAD groups, and this effect was normalized by anti-resistin antiserum. We found that EAT of patients with ACS is characterized by increased expression and secretion of resistin and associated with increased in vitro endothelial cell permeability.

Soluble CD40 ligand levels in essential hypertensive men: evidence of a possible role of insulin resistance

BACKGROUND

Elevated levels of the proinflammatory cytokine soluble CD40 ligand (sCD40L) were reported in subjects with diabetes, impaired glucose tolerance, metabolic syndrome (MS), obesity, and insulin resistance. Metabolic abnormalities might also account for increased sCD40L in subjects with essential hypertension.

METHODS

Several metabolic and vascular correlates of sCD40L levels have been investigated in 90 nondiabetic never-treated essential hypertensive men.

RESULTS

Median sCD40L level was 8.7 ng/ml (interquartile range: 4.9-11.7). On the basis of sCD40L, subjects were divided by tertiles (thresholds at 6.6 and 11.0 ng/ml). The three groups did not differ for age, body mass index (BMI), smokers, blood pressure (BP), prevalence of nondippers, lipids and lipoproteins, renal function, and albuminuria. Carotid intima-media thickness (IMT: 0.79 +/- 0.22, 0.83 +/- 0.29, and 0.85 +/- 0.30 mm) and percentage of subjects with wall thickening (IMT >0.9 to <1.3 mm: 23, 27, and 27%, respectively) were superimposable in the three groups. No differences were observed in high-sensitivity C-reactive protein (hs-CRP) and no correlation emerged between sCD40L and hs-CRP. An increase through sCD40L tertiles emerged for basal insulin (11.2 +/- 5.6, 14.7 +/- 7.7, and 16.8 +/- 13.5 microU/ml, P = 0.10) and fasting glucose (95 +/- 11, 103 +/- 16, and 105 +/- 14 mg/dl, P = 0.028). Consistently, along with the increase in sCD40L, a worsening in insulin sensitivity was observed, which was expressed as homeostasis model assessment for insulin sensitivity (HOMA%S: 99 +/- 52, 77 +/- 43, and 72 +/- 35, P < 0.05), composite insulin sensitivity index (ISIcomp; Matsuda index: 5.11 +/- 2.65, 3.61 +/- 1.98, and 3.28 +/- 1.87, P = 0.025), or oral glucose insulin sensitivity (OGIS) index (OGIS: 421 +/- 67, 386 +/- 90, and 362 +/- 72, P = 0.004).

CONCLUSIONS

In newly diagnosed hypertensive men, sCD40L levels are inversely related to insulin sensitivity, with no correlation with BP, other cardiovascular risk factors, or the degree of subclinical atherosclerosis.

Evaluation of platelet activation in patients supported by the Jarvik 2000* high-rotational speed impeller ventricular assist device

OBJECTIVE

The Jarvik 2000 (Jarvik Heart, Inc, New York, NY) is a thumb-sized high-speed impeller pump that is used as a ventricular assist device in patients with terminal heart failure. Because the Jarvik 2000 is designed for long-term use, it is a central question whether the mechanical forces inside the pump affect blood components. This study evaluated the potential association of the high rotational speed of the Jarvik 2000 with platelet activation, which may result in thromboembolic events.

METHODS

The study group comprised patients with terminal heart failure who were supported with the Jarvik 2000. All were men and received 100 mg aspirin daily. In 8 patients, soluble platelet activation markers (P-selectin and sCD40L), platelet counts, and hemolysis markers (haptoglobin and lactate dehydrogenase levels) were determined. In 5 patients, P-selectin expression and platelet receptor glycoprotein IIb/IIIa activation were determined with flow cytometry and compared with a control group of 5 healthy men. Platelet activation was measured at various rotational device speeds.

RESULTS

After Jarvik 2000 implantation, increased hemolysis was observed, but platelet activation markers and platelet counts were not affected. Increased rotational speed (8000 to 12,000 rpm) of the device also did not result in increased platelet activation.

CONCLUSION

The Jarvik 2000 was not associated with detectable platelet activation, despite high rotational impeller speeds.

Comparative performance of three metabolic syndrome definitions in the prediction of acute coronary syndrome

OBJECTIVE

The value of the recently introduced definitions of metabolic syndrome (MetS) in the identification of high cardiovascular risk subjects remains questionable. We examined the association among different definitions of MetS, and the occurrence of a first-ever acute coronary syndrome (ACS).

METHODS

We studied 211 patients with a first-ever ACS and 210 control subjects. We recorded cardiovascular risk factors and the presence of MetS using 3 different definitions, according to the National Cholesterol Education Program Adult Treatment Panel (NCEP-ATP) III, National Heart, Lung and Blood Institute/American Heart Association (NHLBI/AHA), and International Diabetes Federation (IDF), respectively. The association of MetS with ACS was assessed using univariate and multivariate logistic regression models after adjusting for potential confounding factors, such as gender, age, body mass index, hypertension, diabetes mellitus, and lipids.

RESULTS

ACS cases had a prevalence of metabolic syndrome according to NCEP-ATP III, NHLBI/AHA, and IDF criteria of 72.5%, 81.2%, and 79.1%, respectively. The unadjusted odds ratio (OR) for a first-ever ACS were 2.32 (95% CI: 1.53-3.52, p=0.001), 2.82 (95% CI: 1.79-4.43, p=0.001), and 3.26 (95% CI: 2.12-5.00, p=0.001) for NCEP-ATP III, NHLBI/AHA, and IDF MetS definitions, respectively. Multivariate analyses revealed that only IDF-defined MetS was significantly associated with ACS (OR: 2.23 95% CI: 1.30-3.82, p=0.003), while of the MetS components only waist circumference remained independently associated with ACS (O.R: 1.045 95% CI: 1.014-1.078, p=0.005).

CONCLUSION

The definition of MetS according to the IDF criteria appears to be a better predictor of ACS than NCEP-ATP III and NHLBI/AHA.

C-reactive protein: the harbinger of cardiovascular diseases

Coronary heart disease remains the major cause of mortality and morbidity in the United States and other western countries despite major advances in its treatment. During the last decades, many markers of coronary artery disease have been found which help predict future risk of cardiovascular events. High-sensitivity C-reactive protein has been studied extensively and was seen to be associated with a higher risk of cardiovascular events in patients with acute coronary syndromes and/or peripheral artery disease. Discussed in this review is the latest literature about this marker and its association with cardiovascular disease, as well as the latest therapeutic options available.

Microcirculation and oxidative stress

The microcirculation is a complex and integrated system, transporting oxygen and nutrients to the cells. The key component of this system is the endothelium, contributing to the local balance between pro and anti-inflammatory mediators, hemostatic balance, as well as vascular permeability and cell proliferation. A constant shear stress maintains vascular endothelium homeostasis while perturbed shear stress leads to changes in secretion of vasodilator and vasoconstrictor agents. Increased oxidative stress is a major pathogenetic mechanism of endothelial dysfunction by decreasing NO bioavailability, promoting inflammation and participating in activation of intracellular signals cascade, so influencing ion channels activation, signal transduction pathways, cytoskeleton remodelling, intercellular communication and ultimately gene expression. Targeting the microvascular inflammation and oxidative stress is a fascinating approach for novel therapies in order to decrease morbidity and mortality of chronic and acute diseases.

Circulating Markers Reflect Both Anti- and Pro-Atherogenic Drug Effects in ApoE-Deficient Mice

Background

Current drug therapy of atherosclerosis is focused on treatment of major risk factors, e.g. hypercholesterolemia while in the future direct disease modification might provide additional benefits. However, development of medicines targeting vascular wall disease is complicated by the lack of reliable biomarkers. In this study, we took a novel approach to identify circulating biomarkers indicative of drug efficacy by reducing the complexity of the in vivo system to the level where neither disease progression nor drug treatment was associated with the changes in plasma cholesterol.

Results

ApoE−/− mice were treated with an ACE inhibitor ramipril and HMG-CoA reductase inhibitor simvastatin. Ramipril significantly reduced the size of atherosclerotic plaques in brachiocephalic arteries, however simvastatin paradoxically stimulated atherogenesis. Both effects occurred without changes in plasma cholesterol. Blood and vascular samples were obtained from the same animals. In the whole blood RNA samples, expression of MMP9, CD14 and IL-1RN reflected pro-and anti-atherogenic drug effects. In the plasma, several proteins, e.g. IL-1β, IL-18 and MMP9 followed similar trends while protein readout was less sensitive than RNA analysis.

Conclusion

In this study, we have identified inflammation-related whole blood RNA and plasma protein markers reflecting anti-atherogenic effects of ramipril and pro-atherogenic effects of simwastatin in a mouse model of atherosclerosis. This opens an opportunity for early, non-invasive detection of direct drug effects on atherosclerotic plaques in complex in vivo systems.

Predicting mortality in patients with systemic inflammatory response syndrome: an evaluation of two prognostic models, two soluble receptors, and a macrophage migration inhibitory factor

Better outcomes in patients suspected of community-acquired infections requires the optimal and timely assessment of disease severity at the point of first contact with the health care system, which is typically in the emergency department. This study was conducted using a previously described, prospectively collected cohort of patients with systemic inflammatory response syndrome (SIRS) that were admitted to an emergency department and a department of infectious diseases at a university hospital. Plasma samples were collected and disease severity scores calculated upon admission. A multiplex immunoassay and a newly developed enzyme-linked immunosorbent assay (ELISA)-based assay were used to measure the soluble urokinase-type plasminogen activator receptor, soluble triggering receptor expressed on myeloid cells-1, and macrophage migration inhibitory factor. The area under the receiver operating characteristic (ROC) curve for the prediction of 30- and 180-day mortality was used to compare the performance of the markers and the models. A total of 151 patients were eligible for analysis. Of these, nine died before day 30 and 19 died before day 180 post-admission. Admission-soluble urokinase-type plasminogen activator receptor levels were significantly higher in both day 30 and day 180 non-survivors. There was a non-significant trend towards higher macrophage migration inhibitory factor concentrations in day 30 non-survivors. Soluble triggering receptor expressed on myeloid cells-1 levels were significantly lower in non-survivors at both time points. The simplified acute physiology score II (SAPS II) and sequential organ failure assessment (SOFA) scores were significantly higher in non-survivors at both time points, indicating that these models intended for use in intensive care units might also be useful in an emergency department setting.