Threonine for alanine substitution in the eotaxin (CCL11) gene and the risk of incident myocardial infarction

Recent advances in potential targets for myocardial ischemia reperfusion injury: Role of macrophages

Myocardial ischemia-reperfusion injury (MIRI) is a complex process that occurs when blood flow is restored after myocardium infarction (MI) with exacerbated tissue damage. Macrophages, essential cell type of the immune response, play an important role in MIRI. Macrophage subpopulations, namely M1 and M2, are distinguished by distinct phenotypes and functions. In MIRI, macrophages infiltrate in infarcted area, shaping the inflammatory response and influencing tissue healing. Resident cardiac macrophages interact with monocyte-derived macrophages in MIRI, and influence injury progression. Key factors including chemokines, cytokines, and toll-like receptors modulate macrophage behavior in MIRI. This review aims to address recent findings on the classification and the roles of macrophages in the myocardium, spanning from MI to subsequent MIRI, and highlights various signaling pathways implicated in macrophage polarization underlining the complexity of MIRI. This article will shed light on developing advanced therapeutic strategies for MIRI management.

The Effects of Hypoxic Preconditioned Murine Mesenchymal Stem Cells on Post-Infarct Arrhythmias in the Mouse Model

Ventricular arrhythmias associated with myocardial infarction (MI) have a significant impact on mortality in patients following heart attack. Therefore, targeted reduction of arrhythmia represents a therapeutic approach for the prevention and treatment of severe events after infarction. Recent research transplanting mesenchymal stem cells (MSC) showed their potential in MI therapy. Our study aimed to investigate the effects of MSC injection on post-infarction arrhythmia. We used our murine double infarction model, which we previously established, to more closely mimic the clinical situation and intramyocardially injected hypoxic pre-conditioned murine MSC to the infarction border. Thereafter, various types of arrhythmias were recorded and analyzed. We observed a homogenous distribution of all types of arrhythmias after the first infarction, without any significant differences between the groups. Yet, MSC therapy after double infarction led to a highly significant reduction in simple and complex arrhythmias. Moreover, RNA-sequencing of samples from stem cell treated mice after re-infarction demonstrated a significant decline in most arrhythmias with reduced inflammatory pathways. Additionally, following stem-cell therapy we found numerous highly expressed genes to be either linked to lowering the risk of heart failure, cardiomyopathy or sudden cardiac death. Moreover, genes known to be associated with arrhythmogenesis and key mutations underlying arrhythmias were downregulated. In summary, our stem-cell therapy led to a reduction in cardiac arrhythmias after MI and showed a downregulation of already established inflammatory pathways. Furthermore, our study reveals gene regulation pathways that have a potentially direct influence on arrhythmogenesis after myocardial infarction.

Circulating virome and inflammatory proteome in patients with ST-elevation myocardial infarction and primary ventricular fibrillation

Primary ventricular fibrillation (PVF) is a life-threatening complication of ST-segment elevation myocardial infarction (STEMI). It is unclear what roles viral infection and/or systemic inflammation may play as underlying triggers of PVF, as a second hit in the context of acute ischaemia. Here we aimed to evaluate whether the circulating virome and inflammatory proteome were associated with PVF development in patients with STEMI. Blood samples were obtained from non-PVF and PVF STEMI patients at the time of primary PCI, and from non-STEMI healthy controls. The virome profile was analysed using VirCapSeq-VERT (Virome Capture Sequencing Platform for Vertebrate Viruses), a sequencing platform targeting viral taxa of 342,438 representative sequences, spanning all virus sequence records. The inflammatory proteome was explored with the Olink inflammation panel, using the Proximity Extension Assay technology. After analysing all viral taxa known to infect vertebrates, including humans, we found that non-PVF and PVF patients only significantly differed in the frequencies of viruses in the Gamma-herpesvirinae and Anelloviridae families. In particular, most showed a significantly higher relative frequency in non-PVF STEMI controls. Analysis of systemic inflammation revealed no significant differences between the inflammatory profiles of non-PVF and PVF STEMI patients. Inflammatory proteins associated with cell adhesion, chemotaxis, cellular response to cytokine stimulus, and cell activation proteins involved in immune response (IL6, IL8 CXCL-11, CCL-11, MCP3, MCP4, and ENRAGE) were significantly higher in STEMI patients than non-STEMI controls. CDCP1 and IL18-R1 were significantly higher in PVF patients compared to healthy subjects, but not compared to non-PVF patients. The circulating virome and systemic inflammation were not associated with increased risk of PVF development in acute STEMI. Accordingly, novel strategies are needed to elucidate putative triggers of PVF in the setting of acute ischaemia, in order to reduce STEMI-driven sudden death burden.

Coronary Heart Disease in Type 2 Diabetes Mellitus: Genetic Factors and Their Mechanisms, Gene-Gene, and Gene-Environment Interactions in the Asian Populations

Asians are more susceptible to type 2 diabetes mellitus (T2D) and its coronary heart disease (CHD) complications than the Western populations, possibly due to genetic factors, higher degrees of obesity, insulin resistance, and endothelial dysfunction that could occur even in healthy individuals. The genetic factors and their mechanisms, along with gene-gene and gene-environment interactions associated with CHD in T2D Asians, are yet to be explored. Therefore, the objectives of this paper were to review the current evidence of genetic factors for CHD, summarize the proposed mechanisms of these genes and how they may associate with CHD risk, and review the gene-gene and gene-environment interactions in T2D Asians with CHD. The genetic factors can be grouped according to their involvement in the energy and lipoprotein metabolism, vascular and endothelial pathology, antioxidation, cell cycle regulation, DNA damage repair, hormonal regulation of glucose metabolism, as well as cytoskeletal function and intracellular transport. Meanwhile, interactions between single nucleotide polymorphisms (SNPs) from different genes, SNPs within a single gene, and genetic interaction with environmental factors including obesity, smoking habit, and hyperlipidemia could modify the gene's effect on the disease risk. Collectively, these factors illustrate the complexities of CHD in T2D, specifically among Asians.

PPARA Polymorphism Influences the Cardiovascular Benefit of Fenofibrate in Type 2 Diabetes: Findings From ACCORD-Lipid

The cardiovascular benefits of fibrates have been shown to be heterogeneous and to depend on the presence of atherogenic dyslipidemia. We investigated whether genetic variability in the PPARA gene, coding for the pharmacological target of fibrates (PPAR-α), could be used to improve the selection of patients with type 2 diabetes who may derive cardiovascular benefit from addition of this treatment to statins. We identified a common variant at the PPARA locus (rs6008845, C/T) displaying a study-wide significant influence on the effect of fenofibrate on major cardiovascular events (MACE) among 3,065 self-reported white subjects treated with simvastatin and randomized to fenofibrate or placebo in the ACCORD-Lipid trial. T/T homozygotes (36% of participants) experienced a 51% MACE reduction in response to fenofibrate (hazard ratio 0.49; 95% CI 0.34-0.72), whereas no benefit was observed for other genotypes (P interaction = 3.7 × 10-4). The rs6008845-by-fenofibrate interaction on MACE was replicated in African Americans from ACCORD (N = 585, P = 0.02) and in external cohorts (ACCORD-BP, ORIGIN, and TRIUMPH, total N = 3059, P = 0.005). Remarkably, rs6008845 T/T homozygotes experienced a cardiovascular benefit from fibrate even in the absence of atherogenic dyslipidemia. Among these individuals, but not among carriers of other genotypes, fenofibrate treatment was associated with lower circulating levels of CCL11-a proinflammatory and atherogenic chemokine also known as eotaxin (P for rs6008845-by-fenofibrate interaction = 0.003). The GTEx data set revealed regulatory functions of rs6008845 on PPARA expression in many tissues. In summary, we have found a common PPARA regulatory variant that influences the cardiovascular effects of fenofibrate and that could be used to identify patients with type 2 diabetes who would derive benefit from fenofibrate treatment, in addition to those with atherogenic dyslipidemia.

Role of Allergic Inflammatory Cells in Coronary Artery Disease

Inflammation is an important player both for the initiation and progression of coronary artery disease and for coronary plaque instability. Moreover, inflammation contributes to stent thrombosis and in-stent restenosis after percutaneous coronary intervention. In the past several decades, most studies evaluated the involvement of cellular effectors of classic inflammatory responses, such as monocytes/macrophages, neutrophils, and T cells. Yet, besides classic inflammation, mounting evidence derived from both experimental and clinical studies suggests an important, often unrecognized, role for effector cells of allergic inflammation in both the pathogenesis of coronary artery disease and adverse events following stent implantation. In this review, we discuss the role of effector cells of allergic inflammation in the setting of coronary artery disease progression and instability, and in the occurrence of adverse events following stent implantation, as well. Moreover, we discuss possible therapeutic approaches targeting different specific pathways of allergic inflammatory activation.

The "Aging Factor" Eotaxin-1 (CCL11) Is Detectable in Transfusion Blood Products and Increases with the Donor's Age

Background: High blood levels of the chemokine eotaxin-1 (CCL11) have recently been associated with aging and dementia, as well as impaired memory and learning in humans. Importantly, eotaxin-1 was shown to pass the blood-brain-barrier (BBB) and has been identified as crucial mediator of decreased neurogenesis and cognitive impairment in young mice after being surgically connected to the vessel system of old animals in a parabiosis model. It thus has to be assumed that differences in eotaxin-1 levels between blood donors and recipients might influence cognitive functions also in humans. However, it is unknown if eotaxin-1 is stable during processing and storage of transfusion blood components. This study assesses eotaxin-1 concentrations in fresh-frozen plasma (FFP), erythrocyte concentrate (EC), and platelet concentrate (PC) in dependence of storage time as well as the donor’s age and gender.

Methods: Eotaxin-1 was measured in FFP (n = 168), EC (n = 160) and PC (n = 8) ready-to-use for transfusion employing a Q-Plex immunoassay for eotaxin-1. Absolute quantification of eotaxin-1 was performed with Q-view software.

Results: Eotaxin-1 was consistently detected at a physiological level in FFP and EC but not PC. Eotaxin-1 levels were comparable in male and female donors but increased significantly with rising age of donors in both, FFP and EC. Furthermore, eotaxin-1 was not influenced by storage time of either blood component. Finally, eotaxin-1 is subject to only minor fluctuations within one donor over a longer period of time.

Conclusion: Eotaxin-1 is detectable and stable in FFP and EC and increases with donor’s age. Considering the presumed involvement in aging and cognitive malfunction, differences in donor- and recipient eotaxin-1 levels might affect mental factors after blood transfusion.

Impact of Tag Single Nucleotide Polymorphisms (SNPs) in CCL11 Gene on Risk of Subtypes of Ischemic Stroke in Xinjiang Han Populations

BACKGROUND CCL11 is an important inflammatory cytokine associated with inflammation-related diseases such as atherosclerosis and stroke. The aim of this study was to investigate the relationship between CCL11 gene polymorphism with subtypes of ischemic stroke in Xinjiang Han populations. MATERIAL AND METHODS The improved multiple ligase detection reaction (iMLDR) method was used to analyze the genotypes of 6 tag SNPs in the CCL11 gene (rs1129844, rs17809012, rs1860183, rs1860184, rs4795898, and rs4795895) in a case-control study of 406 lacunar stroke patients, 214 large-artery atherosclerotic (LAA) stroke patients, and 425 controls. RESULTS We found the GG genotype of rs4795895 was significantly associated with increased risk of lacunar stroke (adjusted OR=1.676, 95%CI=1.117-2.515), and the GA genotype of rs17809012 was associated with a significant increase in risk of LAA stroke (adjusted OR=1.337, 95%CI=1.127-1.585). Hypertension stratification analyses showed that the GA genotype of rs17809012 was significantly associated with LAA stroke in the hypertensive group (adjusted OR=1.274, 95%CI=1.015-1.601). In the non-hypertensive group, the GA genotype of rs17809012 was significantly associated with LAA stroke (adjusted OR=1.361, 95%CI=1.041-1.780). The GG genotype of rs4795895 (adjusted OR=1.147, 95%CI=1.115-4.134) and the TT genotype of rs1860184 were significantly associated with lacunar stroke (adjusted OR=2.440, 95%CI=1.550-3.840). CONCLUSIONS This study demonstrates that the CCL11 gene could play an important role in the pathogenesis of lacunar stroke and LAA stroke in the Han population of China.

Oxidized LDL activated eosinophil polarize macrophage phenotype from M2 to M1 through activation of CD36 scavenger receptor

BACKGROUND AND AIMS

Inflammation, particularly innate immunity, plays an important role in cardiovascular diseases. The aim of this study was to investigate whether atherogenic determinants such as oxidized LDL modulate the phenotype of eosinophils.

METHODS

Cultured eosinophils were treated with oxidized LDL and the expression of selective inflammatory and anti-inflammatory cytokines was determined. In addition, the eosinophil receptor and signaling that mediate these events were identified.

RESULTS

Treatment of cultured eosinophils with oxidized LDL (Ox-LDL) specifically induced the expression of IFNα and IFNβ without affecting expression of other proinflammatory cytokines, such as TNFα, IL-1β, and IL-6. In macrophages, Ox-LDL downregulated expression of both IFNα and IFNβ, suggesting that the effect of Ox-LDL on the expression of type I interferons is specific to eosinophils. Furthermore, we noted that eosinophils constitutively expressed IL-4 and IL-13, and Ox-LDL markedly downregulated their expression. Analysis of Ox-LDL signaling revealed that eosinophils constitutively expressed SRB2, CD36, and CD68 scavenger receptors, and Ox-LDL markedly induced the expression of CD36. Further analysis of CD36 signaling by siRNA and neutralizing antibodies showed that the induction of type I IFN by Ox-LDL is mediated by CD36 signaling whereas downregulation of IL-4 is independent of CD36 activation. We further showed that peritoneal macrophages treated with condition medium collected from Ox-LDL treated eosinophils markedly induced the expression of M1 markers such as iNOS, IL6, SOSC3 and TNFα whereas the condition medium from non-treated eosinophils significantly induced expression of M2 markers like ARG1 and CCL24.

CONCLUSIONS

Our data suggest that an atherogenic condition could activate eosinophils and modulate the phenotype of macrophages (from M2 to M1 phenotype), in part, through the CD36 receptor signaling.

Anti-Inflammatory Effects of Metformin Irrespective of Diabetes Status

Supplemental Digital Content is available in the text.

Rationale:

The diabetes mellitus drug metformin is under investigation in cardiovascular disease, but the molecular mechanisms underlying possible benefits are poorly understood.

Objective:

Here, we have studied anti-inflammatory effects of the drug and their relationship to antihyperglycemic properties.

Methods and Results:

In primary hepatocytes from healthy animals, metformin and the IKKβ (inhibitor of kappa B kinase) inhibitor BI605906 both inhibited tumor necrosis factor-α–dependent IκB degradation and expression of proinflammatory mediators interleukin-6, interleukin-1β, and CXCL1/2 (C-X-C motif ligand 1/2). Metformin suppressed IKKα/β activation, an effect that could be separated from some metabolic actions, in that BI605906 did not mimic effects of metformin on lipogenic gene expression, glucose production, and AMP-activated protein kinase activation. Equally AMP-activated protein kinase was not required either for mitochondrial suppression of IκB degradation. Consistent with discrete anti-inflammatory actions, in macrophages, metformin specifically blunted secretion of proinflammatory cytokines, without inhibiting M1/M2 differentiation or activation. In a large treatment naive diabetes mellitus population cohort, we observed differences in the systemic inflammation marker, neutrophil to lymphocyte ratio, after incident treatment with either metformin or sulfonylurea monotherapy. Compared with sulfonylurea exposure, metformin reduced the mean log-transformed neutrophil to lymphocyte ratio after 8 to 16 months by 0.09 U (95% confidence interval, 0.02–0.17; P=0.013) and increased the likelihood that neutrophil to lymphocyte ratio would be lower than baseline after 8 to 16 months (odds ratio, 1.83; 95% confidence interval, 1.22–2.75; P=0.00364). Following up these findings in a double-blind placebo controlled trial in nondiabetic heart failure (trial registration: NCT00473876), metformin suppressed plasma cytokines including the aging-associated cytokine CCL11 (C-C motif chemokine ligand 11).

Conclusion:

We conclude that anti-inflammatory properties of metformin are exerted irrespective of diabetes mellitus status. This may accelerate investigation of drug utility in nondiabetic cardiovascular disease groups.

Clinical Trial Registration:

Name of the trial registry: TAYSIDE trial (Metformin in Insulin Resistant Left Ventricular [LV] Dysfunction). URL: https://www.clinicaltrials.gov. Unique identifier: NCT00473876.

The Relation between eNOS -786 C/T, 4 a/b, MMP-13 rs640198 G/T, Eotaxin 426 C/T, -384 A/G, and 67 G/A Polymorphisms and Long-Term Outcome in Patients with Coronary Artery Disease

Aim. The purpose of this study is to determine the association between eotaxin 426 C/T, −384 A/G, 67 G/A, eNOS −786 T/C, 4 a/b, and MMP-13 rs640198 G/T and prognosis of patients with known CAD. Methods. From total of 1161 patients referred to coronary angiography, 532 patients with angiographically confirmed CAD were selected. Their long-term outcome was followed up using hospital database. Subsequent events were assessed in this study: death or combined endpoint-myocardial infarction, unstable angina pectoris, revascularization, heart failure hospitalization, and cardioverter-defibrillator implantation. Results. The multivariate Cox regression model identified age, smoking, and 3-vessel disease as significant predictors of all-cause death. Further analysis showed that eotaxin 67 G/A (GA + AA versus GG) and eotaxin −384 A/G (GG versus GA + AA) were significant independent prognostic factors when added into the model: HR (95% CI) 2.81 (1.35–5.85), p = 0.006; HR (95% CI) 2.63 (1.19–5.83), p = 0.017; eotaxin −384 A/G was significantly associated with the event-free survival, but it did not provide the prognostic information above the effect of two- or three-vessel disease. Conclusion. The A allele in eotaxin 67 G/A polymorphism is associated with worse survival in CAD patients.

Meta-analyses of four eosinophil related gene variants in coronary heart disease

The goal of our study is to assess the contribution of four eosinophil related gene variants (rs12619285, rs1420101, rs3184504 and rs4143832) to the risk of coronary heart disease (CHD). We conducted four meta-analyses of studies examining the association between four eosinophil related gene variants and the risk of CHD. A systematic search was conducted using MEDLINE, EMBASE, Web of Science and China National Knowledge Infrastructure (CNKI), Wanfang Chinese Periodical. A case-control study was conducted between 162 CHD cases and 119 non-CHD controls to explore their contribution to CHD. For rs3184504 of SH2B3 gene, the meta-analysis was performed among 19 study stages among 94,555 participants. Significant association between rs3184504 and CHD risk was observed in European and South Asian populations (OR = 1.13, 95% CI = 1.10-1.16, p < 0.0001, fixed-effect method). For the other SNPs (rs12619285, rs1420101, and rs4143832), we combined our case-control data with the previous studies and found no association of them with the risk of CHD. No significant contribution of the four genetic variants to CHD was observed in Han Chinese (p > 0.05). In conclusion, our results supported a significant association between rs3184504 of SH2B3 gene and the risk of CHD in Europeans and South Asians, although we were unable to observe association between the four variants and the risk of CHD in Han Chinese.

Resveratrol and its metabolites modulate cytokine-mediated induction of eotaxin-1 in human pulmonary artery endothelial cells

Coronary heart disease (CHD) is a leading cause of death in many developed countries. Evidence has long implicated endothelial injury and inflammation as apical events in the pathogenesis of atherosclerosis, the primary cause of CHD. Numerous risk factors contribute to a damaged, inflamed endothelium. Conversely, cardioprotective agents targeting the dysfunctional endothelium have also been identified, notably from dietary sources. We have used cultured human pulmonary artery endothelial cells (HPAECs) to test the diet-mediated cardioprotective hypothesis. In this review, we summarize our recent findings on control of transcription and expression of inflammation biomarker eotaxin-1 in HPAECs exposed to single or combined proinflammatory cytokines interleukin-13 (IL-13) and tumor necrosis factor-α (TNF-α), and attenuation of the observed eotaxin-1 responses by prior or simultaneous treatment with resveratrol and its metabolites. Control of eotaxin-1 gene regulation may be considered an in vitro model to evaluate agents linking cardioprotection with endothelial cell damage and inflammation.

Touch of chemokines

Chemoattractant cytokines or chemokines constitute a family of structurally related proteins found in vertebrates, bacteria, or viruses. So far, 48 chemokine genes have been identified in humans, which bind to around 20 chemokine receptors. These receptors belong to the seven transmembrane G-protein-coupled receptor family. Chemokines and their receptors were originally studied for their role in cellular trafficking of leukocytes during inflammation and immune surveillance. It is now known that they exert different functions under physiological conditions such as homeostasis, development, tissue repair, and angiogenesis but also under pathological disorders including tumorigenesis, cancer metastasis, inflammatory, and autoimmune diseases. Physicochemical properties of chemokines and chemokine receptors confer the ability to homo- and hetero-oligomerize. Many efforts are currently performed in establishing new therapeutically compounds able to target the chemokine/chemokine receptor system. In this review, we are interested in the role of chemokines in inflammatory disease and leukocyte trafficking with a focus on vascular inflammatory diseases, the operating synergism, and the emerging therapeutic approaches of chemokines.

Association between three single nucleotide polymorphisms in eotaxin (CCL 11) gene, hexanucleotide repetition upstream, severity and course of coronary atherosclerosis

The impact of three single-nucleotide polymorphisms in eotaxin (SCYA11) gene promoter (-426C>T and -384A>G) and first exon (67G>A) and recently described hexanucleotide (GAAGGA)(n) 10.9 kb upstream on coronary atherosclerosis was investigated. Elective coronary angiography of 1050 consecutive subjects was performed. All patients were genotyped for the three SNPs. In a subset of the first 472 samples, the number of (GAAGGA)(n) repetitions was determined. For further evaluation, short and long variants were distinguished; the borderline corresponded with the median value of all alleles: ≤8 repetitions were considered as short sequence, ≥9 repetitions as long. Patients with bronchial asthma or insignificant atherosclerosis were excluded; the remaining group of 933 subjects was further investigated. Patients were grouped according to the form of CAD (ACS vs. stable angina) and the number of diseased vessels. The GG variant of 67 G>A polymorphism was associated with acute form of CAD compared to stable angina (p=0.0011, p(corr.)=0.013). The number of (GAAGGA)(n) repetitions in our set of patients ranged from 3 to 12. There were no subjects with 4 or 5 repetitions. The frequency of short repetition alleles increased with the number of affected vessels (1 vs. 3 diseased vessels: p=0.0043, p(corr)=0.034). In our study, the (GAAGGA)(n) hexanucleotide was associated with the severity of CAD. The 67 GG was associated with acute form of CAD. None of the two SNPs in eotaxin promoter had any relation to CAD. The number of (GAAGGA)(n) repetitions can thus be a novel genetic marker of the extent of CAD.

Independent predictive roles of eotaxin Ala23Thr, paraoxonase 2 Ser311Cys and beta-adrenergic receptor Trp64Arg polymorphisms on cardiac disease in Type 2 Diabetes--an 8-year prospective cohort analysis of 1297 patients

AIMS

To examine the independent and joint effects of multiple genetic variants on a cardiac end-point in an 8-year prospective study of a Chinese diabetic cohort.

METHODS

Seventy-seven single nucleotide polymorphisms (SNPs) of 53 candidate genes for inflammation, thrombosis, vascular tone regulation and lipid metabolism were genotyped in 1297 Chinese patients with no prior history of coronary heart disease (CHD) or heart failure at baseline. Cardiac end-point was defined by the occurrence of CHD and/or heart failure.

RESULTS

In Cox regression model, after adjustment for baseline confounding variables including age, sex, smoking status, duration of diabetes, glycaemic control, lipid levels, waist circumference, blood pressure, albuminuria and estimated glomerular filtration rate, genetic variants, including Ala/Ala of SCYA11 (eotaxin) Ala23Thr, Cys/Cys or Cys/Ser of PON2 (paraoxonase 2) Ser311Cys and Arg/Arg of ADRB3 (beta3-adrenergic receptor) Trp64Arg, were independently associated with incident cardiac end-point, with respective hazard ratios (95% confidence interval) of 1.70 (1.10-2.61, P=0.037), 1.42 (1.08-1.88, P=0.013) and 3.84 (1.18-12.50, P=0.025). Analysis of the joint effect of the risk alleles showed significant increased risk of the cardiac end-point with increasing number of risk alleles (P<0.001). The adjusted risk for the cardiac end-point was 4.11 (P=0.002) for patients carrying four risk alleles compared with those carrying one or no risk allele.

CONCLUSIONS

The independent risk conferred by genetic variants encoding pathways such as inflammation and lipid metabolism, not adequately reflected by conventional biomarkers, may identify high-risk individuals for intensified control of modifiable risk factors.

Eotaxin increases monolayer permeability of human coronary artery endothelial cells

OBJECTIVE

The objective of this study was to determine the effects and molecular mechanisms of eotaxin, a newly discovered chemokine (CCL11), on endothelial permeability in the human coronary artery endothelial cells (HCAECs).

METHODS AND RESULTS

Cells were treated with eotaxin, and the monolayer permeability was studied by using a costar transwell system with a Texas Red-labeled dextran tracer. Eotaxin significantly increased monolayer permeability in a concentration-dependent manner. In addition, eotaxin treatment significantly decreased the mRNA and protein levels of endothelial junction molecules including zonula occludens-1 (ZO-1), occludin, and claudin-1 in a concentration-dependent manner as determined by real-time RT-PCR and Western blot analysis, respectively. Increased oxidative stress was observed in eotaxin-treated HCAECs by analysis of cellular glutathione levels. Furthermore, eotaxin treatment substantially activated the phosphorylation of MAPK p38. HCAECs expressed CCR3. Consequently, antioxidants (ginkgolide B and MnTBAP), specific p38 inhibitor SB203580, and anti-CCR3 antibody effectively blocked the eotaxin-induced permeability increase in HCAECs. Eotaxin also increased the phosphorylation of Stat3 and nuclear translocation of NF-kappaB in HCAECs.

CONCLUSIONS

Eotaxin increases vascular permeability through CCR3, the downregulation of tight junction proteins, increase of oxidative stress, and activation of MAPK p38, Stat3, and NF-kB pathways in HCAECs.

ACE (I/D) polymorphism and response to treatment in coronary artery disease: a comprehensive database and meta-analysis involving study quality evaluation

BACKGROUND

The role of angiotensin-converting enzyme (ACE) gene insertion/deletion (I/D) polymorphism in modifying the response to treatment modalities in coronary artery disease is controversial.

METHODS

PubMed was searched and a database of 58 studies with detailed information regarding ACE I/D polymorphism and response to treatment in coronary artery disease was created. Eligible studies were synthesized using meta-analysis methods, including cumulative meta-analysis. Heterogeneity and study quality issues were explored.

RESULTS

Forty studies involved invasive treatments (coronary angioplasty or coronary artery by-pass grafting) and 18 used conservative treatment options (including anti-hypertensive drugs, lipid lowering therapy and cardiac rehabilitation procedures). Clinical outcomes were investigated by 11 studies, while 47 studies focused on surrogate endpoints. The most studied outcome was the restenosis following coronary angioplasty (34 studies). Heterogeneity among studies (p < 0.01) was revealed and the risk of restenosis following balloon angioplasty was significant under an additive model: the random effects odds ratio was 1.42 (95% confidence interval:1.07-1.91). Cumulative meta-analysis showed a trend of association as information accumulates. The results were affected by population origin and study quality criteria. The meta-analyses for the risk of restenosis following stent angioplasty or after angioplasty and treatment with angiotensin-converting enzyme inhibitors produced non-significant results. The allele contrast random effects odds ratios with the 95% confidence intervals were 1.04(0.92-1.16) and 1.10(0.81-1.48), respectively. Regarding the effect of ACE I/D polymorphism on the response to treatment for the rest outcomes (coronary events, endothelial dysfunction, left ventricular remodeling, progression/regression of atherosclerosis), individual studies showed significance; however, results were discrepant and inconsistent.

CONCLUSION

In view of available evidence, genetic testing of ACE I/D polymorphism prior to clinical decision making is not currently justified. The relation between ACE genetic variation and response to treatment in CAD remains an unresolved issue. The results of long-term and properly designed prospective studies hold the promise for pharmacogenetically tailored therapy in CAD.

Molecular genetics of myocardial infarction

Myocardial infarction (MI) is an important clinical problem because of its large contribution to mortality. The main causal and treatable risk factors for MI include hypertension, hypercholesterolemia or dyslipidemia, diabetes mellitus, and smoking. In addition to these risk factors, recent studies have shown the importance of genetic factors and interactions between multiple genes and environmental factors. Disease prevention is an important strategy for reducing the overall burden of MI, with the identification of markers for disease risk being key both for risk prediction and for potential intervention to lower the chance of future events. Although genetic linkage analyses of families and sib-pairs as well as candidate gene and genome-wide association studies have implicated several loci and candidate genes in predisposition to coronary heart disease (CHD) or MI, the genes that contribute to genetic susceptibility to these conditions remain to be identified definitively. In this review, we summarize both candidate loci for CHD or MI identified by linkage analyses and candidate genes examined by association studies. We also review in more detail studies that have revealed the association with MI or CHD of polymorphisms in MTHFR, LPL, and APOE by the candidate gene approach and those in LTA and at chromosomal region 9p21.3 by genome-wide scans. Such studies may provide insight into the function of implicated genes as well as into the role of genetic factors in the development of CHD and MI.

The chemokine network. II. On how polymorphisms and alternative splicing increase the number of molecular species and configure intricate patterns of disease susceptibility

In this second review on chemokines, we focus on the polymorphisms and alternative splicings and on their consequences in disease. Because chemokines are key mediators in the pathogenesis of inflammatory, autoimmune, vascular and neoplastic disorders, a large number of studies attempting to relate particular polymorphisms of chemokines to given diseases have already been conducted, sometimes with contradictory results. Reviewing the published data, it becomes evident that some chemokine genes that are polymorphic have alleles that are found repeatedly, associated with disease of different aetiologies but sharing some aspects of pathogenesis. Among CXC chemokines, single nucleotide polymorphisms (SNPs) in the CXCL8 and CXCL12 genes stand out, as they have alleles associated with many diseases such as asthma and human immunodeficiency virus (HIV), respectively. Of CC chemokines, the stronger associations occur among alleles from SNPs in CCL2 and CCL5 genes and a number of inflammatory conditions. To understand how chemokines contribute to disease it is also necessary to take into account all the isoforms resulting from differential splicing. The first part of this review deals with polymorphisms and the second with the diversity of molecular species derived from each chemokine gene due to alternative splicing phenomena. The number of molecular species and the level of expression of each of them for every chemokine and for each functionally related group of chemokines reaches a complexity that requires new modelling algorithms akin to those proposed in systems biology approaches.

Association of plasma eotaxin levels with the presence and extent of angiographic coronary artery disease

Eotaxin (CCL11) is an eosinophil-specific chemoattractant which has been found to be highly expressed at sites of vascular pathology. In the present study, we aimed to evaluate the association of plasma eotaxin levels with the presence and extent of angiographic coronary artery disease (CAD). Three hundred and fifty six consecutive patients attending for elective coronary angiography were investigated. Compared with 111 patients without CAD, 245 with CAD showed higher eotaxin concentrations [median (interquartile range): 76.0 (56.3-103.0)pg/ml versus 116.0 (80.5-162.0)pg/ml, respectively; P<0.001]. Importantly, a significant Spearman correlation was found between eotaxin levels and the extent score of coronary artery stenosis (r=0.449, P<0.001). A stepwise increase in plasma levels of eotaxin was also found depending on the number of >50% coronary stenosis: median value 76.0 pg/ml in CAD(-) subjects, 96.0 pg/ml in 1-vessel disease, 128.0 pg/ml in 2-vessel disease, and 129.0 pg/ml in 3-vessel disease (P<0.001 for trend). After confounding variables were controlled for, multiple stepwise regression analysis demonstrated that plasma eotaxin was an independent predictor of angiographic extent of CAD (beta=0.426, P<0.001). Our data suggest that increased eotaxin levels are associated with the presence of CAD and that circulating levels of this chemokine may reflect the extent of coronary atherosclerosis.

Elevated serum monocyte chemoattractant protein-4 and chronic inflammation in overweight subjects

OBJECTIVE

Chronic inflammation observed in obesity has been reported to be implicated in the development of atherosclerosis. We screened candidate chemokines that link chronic inflammation and obesity.

RESEARCH METHODS AND PROCEDURES

Japanese overweight (n = 39, BMI 28.7 +/- 0.65 kg/m(2)) and normal-weight (n = 24, BMI 22.3 +/- 0.45 kg/m(2)) subjects were enrolled. Using antibody-based protein microarray, spot intensities of monocyte chemoattractant protein (MCP)-4, eotaxin, and eotaxin-2 correlated with anthropometric parameters. We further measured serum concentration of these chemokines and mRNA levels in adipose tissues obtained from volunteers.

RESULTS

Serum MCP-4 levels showed positive correlation with BMI (r = 0.318, p = 0.014), waist (r = 0.316, p = 0.018), and waist-to-hip ratio (WHR) (r = 0.264, p = 0.049). Furthermore, MCP-4 correlated with homeostasis model assessment of insulin resistance (r = 0.392, p = 0.002), high-sensitivity C-reactive protein (hsCRP) (r = 0.350, p = 0.006). In step-wise multiple regression analyses, hsCRP independently correlated with MCP-4 levels. The expression of MCP-4 mRNA in visceral adipose tissue positively correlates with BMI. Serum eotaxin levels correlate with BMI (r = 0.262, p = 0.045) and WHR (r = 0.383, p = 0.003). Serum eotaxin-2 levels correlated with BMI (r = 0.464, p < 0.001), waist (r = 0.333, p = 0.017), and WHR (r = 0.278, p = 0.048). However, eotaxin and eotaxin-2 levels did not show significant correlation with hsCRP.

DISCUSSION

Serum levels of MCP-4, eotaxin, and eotaxin-2, which belong to CC chemokine family and share CC chemokine receptor 3, correlated with BMI. These chemokines, especially MCP-4, may be critical molecules that link obesity and chronic inflammation.

Markers of eosinophilic inflammation and risk prediction in patients with coronary artery disease

BACKGROUND

The eotaxin family comprises three distinct peptides (eotaxin, eotaxin-2 and eotaxin-3) which have been implicated in eosinophilic inflammation. In vitro and clinical studies suggest that eotaxins could play a role in vascular inflammation, but no data are available on their prognostic significance in patients with angiographically documented coronary artery disease (CAD).

MATERIALS AND METHODS

Baseline plasma samples were obtained from 1014 patients with documented CAD. We tested the predictive effect of markers of eosinophilic inflammation and C-reactive protein (CRP) on death from cardiovascular causes and nonfatal myocardial infarction over a 2.7-4.1-year follow-up period.

RESULTS

Unexpectedly, lower eotaxin-3 concentrations were observed in patients with adverse cardiovascular events, whereas both eotaxin and eotaxin-2 showed no association with risk. After adjustment for most potential confounders, patients in the upper-quartile of eotaxin-3 levels had a 0.42 hazard-ratio (95% CI, 0.29-0.61, P < 0.001) for adverse events compared with subjects in the lower-quartile. The highest risk of future cardiovascular events was observed in subjects with combined elevation of CRP and reduction of eotaxin-3; 4.4 hazard-ratio (95% CI, 2.1-9.5, P < 0.001). Importantly, receiver-operating-characteristic curves analysis suggested a superior prognostic value of eotaxin-3 compared with CRP for predicting cardiac events in patients with CAD.

CONCLUSIONS

Low levels of eotaxin-3 are an independent predictor of future adverse cardiovascular events in patients with CAD and may be useful for risk stratification.

Influence of eotaxin 67G>A polymorphism on plasma eotaxin concentrations in myocardial infarction survivors and healthy controls

Eotaxin (CCL11) is a CC chemokine, whose systemic levels might be associated with coronary artery disease (CAD) and genetic variants predispose to the myocardial infarction (MI). However, the relationship between eotaxin genetic variants and plasma concentrations in CAD patients is still incompletely characterized. We genotyped 311 patients, who survived first MI and 338 controls for a 67G>A single nucleotide polymorphism in the eotaxin gene. By measuring plasma eotaxin concentrations in those subjects we related the former to the presence of 67G>A SNP. There were no differences in eotaxin genotype frequencies between patients and controls. Patient G/G carriers had higher circulating eotaxin levels compared both to G/A and A/A patients (P=0.046) and G/G controls (P=0.028), which might indicate the influence of additional factors (e.g. inflammatory mediators) on eotaxin secretion in those patients. At the same time, eotaxin levels did not differ between patients and controls irrespective of the 67G>A SNP variants they carried. There were no associations between plasma eotaxin levels, biochemical indicators of CAD and the degree of coronary artery stenosis in post-MI patients. Interestingly, some medications taken by the patients (e.g. diuretics and short-acting nitrates) might affect plasma eotaxin levels. In conclusion, our results show that there is no clear association between the presence of eotaxin 67G>A SNP, its plasma levels and CAD parameters in post-MI patients and that circulating eotaxin levels do not differ between subjects with clinical manifestations of coronary atherosclerosis and healthy controls.

Multi-locus candidate gene polymorphisms and risk of myocardial infarction: a population-based, prospective genetic analysis

BACKGROUND

Polymorphisms in candidate genes related to lipid metabolism, thrombosis, hemostasis, cell-matrix adhesion, and inflammation have been suggested clinically useful in risk assessment of cardiovascular disease.

METHODS

We evaluated a panel of 92 candidate gene polymorphisms, using a multiplex polymerase chain reaction-immobilized probe assay amongst 523 individuals who subsequently developed myocardial infarction (MI), and amongst 2092 individuals who remained free of reported cardiovascular disease over a mean follow-up period of 13.2 years.

RESULTS

Of the 92 polymorphisms tested, three that we previously reported on were associated with risk of MI, [pro12ala in the peroxisome proliferator activated-receptor gamma gene (odds ratio, OR = 0.75, P = 0.02); thr164ile in the beta-2 adrenergic receptor gene (OR = 0.14, P = 0.007); and ala23thr polymorphism in the eotaxin gene (OR = 1.87, P = 0.01)]. However, when adjusted for the other 89 polymorphisms evaluated, these findings were no longer statistically significant. Further, in contrast to reports from other investigators, we found little evidence for association of a C677T polymorphism in the 5,10-methylenetetrahydrofolate reductase gene, the angiotensin-I-converting enzyme 1 insertion/deletion polymorphism, a 4G/5G polymorphism in the serine/cysteine proteinase inhibitor-clade E-member 1 gene, the factor V Leiden mutation, the G20210A factor II mutation, a -455G>A polymorphism in the beta-fibrinogen gene, the cys112arg/arg158cys apolipoprotein E gene polymorphism, a gly460trp polymorphism in the alpha-adducin gene, and a -629C>A polymorphism in the cholesteryl ester transfer protein gene with risk of MI.

CONCLUSIONS

After correction for multiple comparisons, the addition of genetic information observed in the present study had little impact on risk prediction models for MI. The present investigation highlights the importance of replication and validation of findings from genetic association studies.

Interaction between inflammation-related gene polymorphisms and cigarette smoking on the risk of myocardial infarction in the Physician’s Health Study

Inflammation is known to be a major component of atherosclerosis, and cigarette smoking is known to induce a systemic inflammatory response. We therefore, investigated possible gene-environment interactions between various inflammation-related gene polymorphisms and cigarette smoking on the risk of myocardial infarction (MI) in the Physician's Health Study (PHS), a cohort of initially healthy middle-aged men. We used a nested case-control design consisting of 522 MI cases and 2,089 controls derived from PHS. Eleven inflammatory polymorphisms were studied using logistic regression analysis: eotaxin (ala23thr), intercellular adhesion molecule 1 (gly241arg), interleukin-4 (582C>T), interleukin-4 receptor (ile75val, gln576arg), interleukin-6 (-174G>C), interleukin-10 (-571C>A), P-selectin (val640leu, thr756pro, ser330asn), and vascular cell adhesion molecule 1 (-1594T>C). Interactions of smoking with all the three modes of inheritance (additive, dominant, recessive) were tested. Statistically significant (P<0.05) interaction terms were found for interleukin-4 receptor (ile75val), with odds ratios of 0.52 (95%CI:0.29-0.95) for Ile-Val and 0.34 (95%CI:0.14-0.83) for Val-Val, compared to the wildtype Ile-Ile; for interleukin-6 (-174G>C) with odds ratios of 2.16 (1.14-4.09) for GC and 0.81 (0.31-2.12) for CC, compared to the wildtype GG; and for P-selectin (ser330asn) with odds ratios of 0.48 (0.24-0.95) for Ser-Asn and 1.08 (0.29-3.93) for Asn-Asn, compared to the wildtype Ser-Ser, with these effects occurring only among the smokers. These data raise the possibility of interaction between the smoking status and certain inflammatory polymorphisms on the risk of MI in men. However, these results should be interpreted with caution due to the potential for false positive results that can arise from analyses with multiple comparisons.