Systematic Evaluation of Pleiotropy Identifies 6 Further Loci Associated With Coronary Artery Disease.

BACKGROUND: Genome-wide association studies have so far identified 56 loci associated with risk of coronary artery disease (CAD). Many CAD loci show pleiotropy; that is, they are also associated with other diseases or traits. OBJECTIVES: This study sought to systematically test if genetic variants identified for non-CAD diseases/traits also associate with CAD and to undertake a comprehensive analysis of the extent of pleiotropy of all CAD loci. METHODS: In discovery analyses involving 42,335 CAD cases and 78,240 control subjects we tested the association of 29,383 common (minor allele frequency >5%) single nucleotide polymorphisms available on the exome array, which included a substantial proportion of known or suspected single nucleotide polymorphisms associated with common diseases or traits as of 2011. Suggestive association signals were replicated in an additional 30,533 cases and 42,530 control subjects. To evaluate pleiotropy, we tested CAD loci for association with cardiovascular risk factors (lipid traits, blood pressure phenotypes, body mass index, diabetes, and smoking behavior), as well as with other diseases/traits through interrogation of currently available genome-wide association study catalogs. RESULTS: We identified 6 new loci associated with CAD at genome-wide significance: on 2q37 (KCNJ13-GIGYF2), 6p21 (C2), 11p15 (MRVI1-CTR9), 12q13 (LRP1), 12q24 (SCARB1), and 16q13 (CETP). Risk allele frequencies ranged from 0.15 to 0.86, and odds ratio per copy of the risk allele ranged from 1.04 to 1.09. Of 62 new and known CAD loci, 24 (38.7%) showed statistical association with a traditional cardiovascular risk factor, with some showing multiple associations, and 29 (47%) showed associations at p < 1 × 10-4 with a range of other diseases/traits. CONCLUSIONS: We identified 6 loci associated with CAD at genome-wide significance. Several CAD loci show substantial pleiotropy, which may help us understand the mechanisms by which these loci affect CAD risk.

Coding Variation in ANGPTL4, LPL, and SVEP1 and the Risk of Coronary Disease.

BACKGROUND: The discovery of low-frequency coding variants affecting the risk of coronary artery disease has facilitated the identification of therapeutic targets. METHODS: Through DNA genotyping, we tested 54,003 coding-sequence variants covering 13,715 human genes in up to 72,868 patients with coronary artery disease and 120,770 controls who did not have coronary artery disease. Through DNA sequencing, we studied the effects of loss-of-function mutations in selected genes. RESULTS: We confirmed previously observed significant associations between coronary artery disease and low-frequency missense variants in the genes LPA and PCSK9. We also found significant associations between coronary artery disease and low-frequency missense variants in the genes SVEP1 (p.D2702G; minor-allele frequency, 3.60%; odds ratio for disease, 1.14; P=4.2×10(-10)) and ANGPTL4 (p.E40K; minor-allele frequency, 2.01%; odds ratio, 0.86; P=4.0×10(-8)), which encodes angiopoietin-like 4. Through sequencing of ANGPTL4, we identified 9 carriers of loss-of-function mutations among 6924 patients with myocardial infarction, as compared with 19 carriers among 6834 controls (odds ratio, 0.47; P=0.04); carriers of ANGPTL4 loss-of-function alleles had triglyceride levels that were 35% lower than the levels among persons who did not carry a loss-of-function allele (P=0.003). ANGPTL4 inhibits lipoprotein lipase; we therefore searched for mutations in LPL and identified a loss-of-function variant that was associated with an increased risk of coronary artery disease (p.D36N; minor-allele frequency, 1.9%; odds ratio, 1.13; P=2.0×10(-4)) and a gain-of-function variant that was associated with protection from coronary artery disease (p.S447*; minor-allele frequency, 9.9%; odds ratio, 0.94; P=2.5×10(-7)). CONCLUSIONS: We found that carriers of loss-of-function mutations in ANGPTL4 had triglyceride levels that were lower than those among noncarriers; these mutations were also associated with protection from coronary artery disease. (Funded by the National Institutes of Health and others.).

A genome-wide association study identifies 6p21 as novel risk locus for dilated cardiomyopathy.

AIMS: Dilated cardiomyopathy (DCM) is one of the leading causes for cardiac transplantations and accounts for up to one-third of all heart failure cases. Since extrinsic and monogenic causes explain only a fraction of all cases, common genetic variants are suspected to contribute to the pathogenesis of DCM, its age of onset, and clinical progression. By a large-scale case-control genome-wide association study we aimed here to identify novel genetic risk loci for DCM. METHODS AND RESULTS: Applying a three-staged study design, we analysed more than 4100 DCM cases and 7600 controls. We identified and successfully replicated multiple single nucleotide polymorphism on chromosome 6p21. In the combined analysis, the most significant association signal was obtained for rs9262636 (P = 4.90 × 10(-9)) located in HCG22, which could again be replicated in an independent cohort. Taking advantage of expression quantitative trait loci (eQTL) as molecular phenotypes, we identified rs9262636 as an eQTL for several closely located genes encoding class I and class II major histocompatibility complex heavy chain receptors. CONCLUSION: The present study reveals a novel genetic susceptibility locus that clearly underlines the role of genetically driven, inflammatory processes in the pathogenesis of idiopathic DCM.

The large non-coding RNA ANRIL, which is associated with atherosclerosis, periodontitis and several forms of cancer, regulates ADIPOR1, VAMP3 and C11ORF10.

The long non-coding RNA ANRIL is the best replicated genetic risk locus of coronary artery disease (CAD) and periodontitis (PD), and is independently associated with a variety of other immune-mediated and metabolic disorders and several forms of cancer. Recent studies showed a correlation of decreased concentrations of proximal ANRIL transcripts with homozygous carriership of the CAD and PD main risk alleles. To elucidate the relation of these transcripts to disease manifestation, we constructed a short hairpin RNA in a stable inducible knock-down system of T-Rex 293 HEK cell lines, specifically targeting the proximal transcripts EU741058 and DQ485454. By genome-wide expression profiling using Affymetrix HG1.0 ST Arrays, we identified the transcription of ADIPOR1, VAMP3 and C11ORF10 to be correlated with decreased ANRIL expression in a time-dependent manner. We validated these findings on a transcriptional and translational level in different cell types. Exploration of the identified genes for the presence of disease associated variants, using Affymetrix 500K genotyping and Illumina custom genotyping arrays, highlighted a region upstream of VAMP3 within CAMTA1 to be associated with increased risk of CAD [rs10864294 P = 0.015, odds ratio (OR) = 1.30, 95% confidence interval (CI) = 1.1-1.6, 1471 cases, 2737 controls] and aggressive PD (AgP; P = 0.008, OR = 1.31, 95% CI = 1.1-1.6, 864 cases, 3664 controls). In silico replication in a meta-analysis of 14 genome-wide association studies of CAD of the CARDIoGRAM Consortium identified rs2301462, located on the same haplotype block, as associated with P = 0.001 upon adjustment for sex and age. Our results give evidence that specific isoforms of ANRIL regulate key genes of glucose and fatty acid metabolism.

Association between the chromosome 9p21 locus and angiographic coronary artery disease burden: a collaborative meta-analysis.

OBJECTIVES: This study sought to ascertain the relationship of 9p21 locus with: 1) angiographic coronary artery disease (CAD) burden; and 2) myocardial infarction (MI) in individuals with underlying CAD. BACKGROUND: Chromosome 9p21 variants have been robustly associated with coronary heart disease, but questions remain on the mechanism of risk, specifically whether the locus contributes to coronary atheroma burden or plaque instability. METHODS: We established a collaboration of 21 studies consisting of 33,673 subjects with information on both CAD (clinical or angiographic) and MI status along with 9p21 genotype. Tabular data are provided for each cohort on the presence and burden of angiographic CAD, MI cases with underlying CAD, and the diabetic status of all subjects. RESULTS: We first confirmed an association between 9p21 and CAD with angiographically defined cases and control subjects (pooled odds ratio [OR]: 1.31, 95% confidence interval [CI]: 1.20 to 1.43). Among subjects with angiographic CAD (n = 20,987), random-effects model identified an association with multivessel CAD, compared with those with single-vessel disease (OR: 1.10, 95% CI: 1.04 to 1.17)/copy of risk allele). Genotypic models showed an OR of 1.15, 95% CI: 1.04 to 1.26 for heterozygous carrier and OR: 1.23, 95% CI: 1.08 to 1.39 for homozygous carrier. Finally, there was no significant association between 9p21 and prevalent MI when both cases (n = 17,791) and control subjects (n = 15,882) had underlying CAD (OR: 0.99, 95% CI: 0.95 to 1.03)/risk allele. CONCLUSIONS: The 9p21 locus shows convincing association with greater burden of CAD but not with MI in the presence of underlying CAD. This adds further weight to the hypothesis that 9p21 locus primarily mediates an atherosclerotic phenotype.

Genome-wide association study identifies a new locus for coronary artery disease on chromosome 10p11.23.

AIMS: Recent genome-wide association (GWA) studies identified 10 chromosomal loci for coronary artery disease (CAD) or myocardial infarction (MI). However, these loci explain only a small proportion of the genetic variability of these pertinent diseases. We sought to identify additional CAD/MI loci by applying a three-stage approach. METHODS AND RESULTS: We genotyped n = 1157 MI cases and n = 1748 controls from a population-based study population [German MI Family Study (GerMIFS) III (KORA)] with genome-wide SNP arrays. At this first stage, n = 462 SNPs showed association with MI at P<1 × 10(-3) in two-sided logistic regression. In a second stage, 415 of these SNPs were evaluated in silico in two independent GWA samples, the GerMIFS I (875 cases/1644 controls) and GerMIFS II (1222 cases/1298 controls). Nine SNPs, representing three regions, displayed consistent replication in this in silico analysis (P<0.05 for each GWA sample): five SNPs at 9p21.3, a well-known CAD/MI locus, two SNPs at 10p11.21, and two SNPs at 2p24.3. Wet-lab replication, i.e. the third stage, of SNP rs3739998 (representing the novel locus at 10p11.21, p.S1002T in the KIAA1462 gene) in additional 5790 cases and 5302 controls confirmed the association (P=9.54 × 10(-4)), but not for the 2p24.3 locus. The combined P-value across all stages for SNP rs3739998 is P=1.27 × 10(-11) [odds ratio (OR) = 1.15 (1.11-1.20)]. CONCLUSION: Analysis of a GWA study followed by in silico and wet-lab replication steps identified the KIAA1462 gene, encoding a yet uncharacterized protein, on chromosome 10p11.23 with genome-wide significant association for CAD/MI. Further studies are needed to characterize the functional role of this locus in the aetiology of these diseases.

Platelet-activating factor levels of serum and gingival crevicular fluid in nonsmoking patients with periodontitis and/or coronary heart disease.

The purpose of the present study was to investigate systemic and local levels of platelet-activating factor (PAF), a potent proinflammatory mediator implicated in cardiovascular pathophysiology in adult nonsmoking patients with periodontitis with or without coronary heart disease (CHD). Eighty-seven volunteers, 25 periodontitis patients, 19 periodontitis with CHD patients, 19 CHD patients, and 24 healthy controls were included, and periodontal conditions were assessed. Gingival crevicular fluid (GCF) and venous blood were collected, and PAF levels were measured by enzyme-linked immunosorbent assay. PAF levels in serum (303.3 ± 204 pg/ml) and in GCF (26.3 ± 6 pg/µl) of the periodontitis group with CHD, the periodontitis group (serum, 302.4 ± 241 pg/ml and GCF, 26.3 ± 8 pg/µl) and the CHD group (serum, 284.7 ± 192 pg/ml and GCF, 20.8 ± 6 pg/µl) were significantly higher than the healthy control group (serum, 65.4 ± 35 pg/ml and GCF, 7.7 ± 3 pg/µl; p < 0.05). In summary, the present study could demonstrate that in patients with periodontitis, the inflammatory mediator PAF is released into serum at least in the same range as for patients with coronary heart disease. However, no additive effects were seen when both conditions were present.

Identification of a shared genetic susceptibility locus for coronary heart disease and periodontitis.

Recent studies indicate a mutual epidemiological relationship between coronary heart disease (CHD) and periodontitis. Both diseases are associated with similar risk factors and are characterized by a chronic inflammatory process. In a candidate-gene association study, we identify an association of a genetic susceptibility locus shared by both diseases. We confirm the known association of two neighboring linkage disequilibrium regions on human chromosome 9p21.3 with CHD and show the additional strong association of these loci with the risk of aggressive periodontitis. For the lead SNP of the main associated linkage disequilibrium region, rs1333048, the odds ratio of the autosomal-recessive mode of inheritance is 1.99 (95% confidence interval 1.33-2.94; P = 6.9 x 10(-4)) for generalized aggressive periodontitis, and 1.72 (1.06-2.76; P = 2.6 x 10(-2)) for localized aggressive periodontitis. The two associated linkage disequilibrium regions map to the sequence of the large antisense noncoding RNA ANRIL, which partly overlaps regulatory and coding sequences of CDKN2A/CDKN2B. A closely located diabetes-associated variant was independent of the CHD and periodontitis risk haplotypes. Our study demonstrates that CHD and periodontitis are genetically related by at least one susceptibility locus, which is possibly involved in ANRIL activity and independent of diabetes associated risk variants within this region. Elucidation of the interplay of ANRIL transcript variants and their involvement in increased susceptibility to the interactive diseases CHD and periodontitis promises new insight into the underlying shared pathogenic mechanisms of these complex common diseases.

New susceptibility locus for coronary artery disease on chromosome 3q22.3.

We present a three-stage analysis of genome-wide SNP data in 1,222 German individuals with myocardial infarction and 1,298 controls, in silico replication in three additional genome-wide datasets of coronary artery disease (CAD) and subsequent replication in approximately 25,000 subjects. We identified one new CAD risk locus on 3q22.3 in MRAS (P = 7.44 x 10(-13); OR = 1.15, 95% CI = 1.11-1.19), and suggestive association with a locus on 12q24.31 near HNF1A-C12orf43 (P = 4.81 x 10(-7); OR = 1.08, 95% CI = 1.05-1.11).

HBEGF, SRA1, and IK: Three cosegregating genes as determinants of cardiomyopathy.

Human dilated cardiomyopathy (DCM), a disorder of the cardiac muscle, causes considerable morbidity and mortality and is one of the major causes of sudden cardiac death. Genetic factors play a role in the etiology and pathogenesis of DCM. Disease-associated genetic variations identified to date have been identified in single families or single sporadic patients and explain a minority of the etiology of DCM. We show that a 600-kb region of linkage disequilibrium (LD) on 5q31.2-3, harboring multiple genes, is associated with cardiomyopathy in three independent Caucasian populations (combined P-value = 0.00087). Functional assessment in zebrafish demonstrates that at least three genes, orthologous to loci in this LD block, HBEGF, IK, and SRA1, result independently in a phenotype of myocardial contractile dysfunction when their expression is reduced with morpholino antisense reagents. Evolutionary analysis across multiple vertebrate genomes suggests that this heart failure-associated LD block emerged by a series of genomic rearrangements across amphibian, avian, and mammalian genomes and is maintained as a cluster in mammals. Taken together, these observations challenge the simple notion that disease phenotypes can be traced to altered function of a single locus within a haplotype and suggest that a more detailed assessment of causality can be necessary.

Lifelong reduction of LDL-cholesterol related to a common variant in the LDL-receptor gene decreases the risk of coronary artery disease--a Mendelian Randomisation study.

BACKGROUND: Rare mutations of the low-density lipoprotein receptor gene (LDLR) cause familial hypercholesterolemia, which increases the risk for coronary artery disease (CAD). Less is known about the implications of common genetic variation in the LDLR gene regarding the variability of cholesterol levels and risk of CAD. METHODS: Imputed genotype data at the LDLR locus on 1 644 individuals of a population-based sample were explored for association with LDL-C level. Replication of association with LDL-C level was sought for the most significant single nucleotide polymorphism (SNP) within the LDLR gene in three European samples comprising 6 642 adults and 533 children. Association of this SNP with CAD was examined in six case-control studies involving more than 15 000 individuals. FINDINGS: Each copy of the minor T allele of SNP rs2228671 within LDLR (frequency 11%) was related to a decrease of LDL-C levels by 0.19 mmol/L (95% confidence interval (CI) [0.13-0.24] mmol/L, p = 1.5x10(-10)). This association with LDL-C was uniformly found in children, men, and women of all samples studied. In parallel, the T allele of rs2228671 was associated with a significantly lower risk of CAD (Odds Ratio per copy of the T allele: 0.82, 95% CI [0.76-0.89], p = 2.1x10(-7)). Adjustment for LDL-C levels by logistic regression or Mendelian Randomisation models abolished the significant association between rs2228671 with CAD completely, indicating a functional link between the genetic variant at the LDLR gene locus, change in LDL-C and risk of CAD. CONCLUSION: A common variant at the LDLR gene locus affects LDL-C levels and, thereby, the risk for CAD.

Standardized quantification of pulmonary fibrosis in histological samples.

The Ashcroft scale for the evaluation of bleomycin-induced lung fibrosis is the analysis of stained histological samples by visual assessment. Based on the knowledge that this procedure is not standardized in animals and results are highly variable, we hypothesized that modification of this method may improve quantification of lung fibrosis in small animals. To prove our hypothesis, we evaluated pulmonary fibrosis in Lewis rats induced by a single intratracheal injection of 0.3 mg/kg body weight bleomycin (n = 13) compared with the same amount of saline in a control group (n = 4). We modified the Ashcroft scale by precisely defining the assignment of grades from 0 to 8 for the increasing extent of fibrosis in lung histological samples. Thirty-two observers were randomly assigned to evaluate 108 photographs of slides using either the Ashcroft scale or the modified scale. Consistent with our hypothesis, there was a significant reduction in the variability of standard deviations with the modified scale compared with the Ashcroft scale (mean of variability 0.25 versus 0.62, P < 0.0001). Applying the kappa index, the Ashcroft scale showed only a fair to moderate agreement (0.23-0.59) between the observers and a low intra-observer agreement (0.51-0.74) in contrast to the modified scale, which demonstrated a moderate to good agreement between the observers (0.65-0.93, P < 0.0001) and a high intra-observer agreement (0.87-0.91, P < 0.05). To test the modified scale in vivo, we compared both scales with the results of computed tomography (CT) of the lungs obtained from the same mice. In agreement, the modified scale demonstrated a better correlation to CT scans (R = 0.58) compared with the Ashcroft scale (R = 0.33). In summary, quantification of lung fibrosis in histological lung sections using the modified scale is reliable and reproducible.

Repeated replication and a prospective meta-analysis of the association between chromosome 9p21.3 and coronary artery disease.

BACKGROUND: Recently, genome-wide association studies identified variants on chromosome 9p21.3 as affecting the risk of coronary artery disease (CAD). We investigated the association of this locus with CAD in 7 case-control studies and undertook a meta-analysis. METHODS AND RESULTS: A single-nucleotide polymorphism (SNP), rs1333049, representing the 9p21.3 locus, was genotyped in 7 case-control studies involving a total of 4645 patients with myocardial infarction or CAD and 5177 controls. The mode of inheritance was determined. In addition, in 5 of the 7 studies, we genotyped 3 additional SNPs to assess a risk-associated haplotype (ACAC). Finally, a meta-analysis of the present data and previously published samples was conducted. A limited fine mapping of the locus was performed. The risk allele (C) of the lead SNP, rs1333049, was uniformly associated with CAD in each study (P<0.05). In a pooled analysis, the odds ratio per copy of the risk allele was 1.29 (95% confidence interval, 1.22 to 1.37; P=0.0001). Haplotype analysis further suggested that this effect was not homogeneous across the haplotypic background (test for interaction, P=0.0079). An autosomal-additive mode of inheritance best explained the underlying association. The meta-analysis of the rs1333049 SNP in 12,004 cases and 28,949 controls increased the overall level of evidence for association with CAD to P=6.04x10(-10) (odds ratio, 1.24; 95% confidence interval, 1.20 to 1.29). Genotyping of 31 additional SNPs in the region identified several with a highly significant association with CAD, but none had predictive information beyond that of the rs1333049 SNP. CONCLUSIONS: This broad replication provides unprecedented evidence for association between genetic variants at chromosome 9p21.3 and risk of CAD.

NT-proBNP is not elevated in patients with obstructive sleep apnoea.

BACKGROUND: N-terminal pro-brain natriuretic peptide (NT-ProBNP) has emerged as an important marker of cardiac stress and may reflect the severity of underlying cardiac dysfunction, which is thought to be associated with obstructive sleep apnoea syndrome (OSAS). METHODS: This study evaluated the plasma concentration of NT-ProBNP in 60 consecutive patients (median age 55.7 years, median body mass index (BMI) 31.8) who were referred to a sleep laboratory with a suspicion of OSAS. Each subject underwent measurement of morning NT-ProBNP plasma levels, polysomnography and echocardiography. Patients were treated with nasal continuous or bilevel positive airway pressure ventilation (nCPAP/BIPAP) or without mechanical respiratory support, depending on clinical symptoms and results of polysomnography. Three months after treatment of OSAS 28 of the patients were reassessed for re-evaluation of NT-ProBNP and polysomnography. RESULTS: Low or high levels of NT-proBNP were not associated with AHI and other sleep related indices (p>0.3). There was no correlation between NT-proBNP and AHI or other sleep related indices. In multiple regression analysis, NT-proBNP was significantly correlated with left ventricular ejection fraction, creatinine clearance and the presence of systemic arterial hypertension but not with AHI. CONCLUSIONS: Our results show by a robust multiple regression analysis, that NT-pro BNP is not associated with OSAS and NT-pro BNP cannot be used as a sensitive marker for underlying cardiovascular abnormalities in patients with OSAS.

Inotropic therapy for cardiac low output syndrome: comparison of hemodynamic effects of dopamine/dobutamine versus dopamine/dopexamine.

OBJECTIVE: To examine the effects of a therapy with dopexamine/dopamine in comparison with a regimen of dobutamine/dopamine on the outcome of patients with profound cardiogenic shock. MATERIAL AND METHODS: Twenty patients presenting with an acute cardiogenic shock assisted with mechanical ventilation, being refractory to a therapy with dopamine alone were analyzed. After persistence of low cardiac output syndrome (cardiac index <2.5 l/min/m2) was confirmed, patients were treated either with receiving dopexamine (2 microg/kg/min) (group 1) or dobutamine (6 microg/kg/min) (group 2) in combination with dopamine (6 microg/kg/min) for 24 hrs. Hemodynamic parameters, urine production and clinical outcome were measured at intervals throughout the study. The groups were similar with respect to demographics and risk factors and there were no significant differences in the supportive treatment and hemodynamics at baseline. RESULTS: The dopexamine treated patients had lower myocardial oxygen consumption (9310 +/- 2243 mmHg O2/sec vs. 10621 +/- 2552 mmHg O2/sec) and lower mean arterial pressure (66 +/- 11 mmHg vs. 71 +/- 10 mmHg) after the 24 hrs treatment interval, but no one of the changes reached statistical significance. No differences were found between the two groups for other variables and the overall clinical outcome. CONCLUSION: The present study revealed that neither substance is superior in the treatment of cardiogenic shock, even if the effect on myocardial consumption and the reported beneficial effects on renal and splanchnic functions might favour the use of dopexamine under certain circumstances.

Fungal rDNA signatures in coronary atherosclerotic plaques.

Bacterial DNA has been found in coronary plaques and it has therefore been concluded that bacteria may play a role as trigger factors in the chronic inflammatory process underlying coronary atherosclerosis. However, the microbial spectrum is complex and it is not known whether microorganisms other than bacteria are involved in coronary disease. Fungal 18S rDNA signatures were systematically investigated in atherosclerotic tissue obtained through catheter-based atherectomy of 38 patients and controls (unaffected coronary arteries) using clone libraries, denaturating gradient gel analysis (DGGE), in situ hybridization and fluorescence in situ hybridization (FISH). Fungal DNA was found in 35 of 38 (92.11%) coronary heart disease patients by either polymerase chain reaction (PCR) with universal primers or in situ hybridization analysis (n = 5), but not in any control sample. In a clone library with more than 350 sequenced clones from pooled patient DNA, an overall richness of 19 different fungal phylotypes could be observed. Fungal profiles of coronary heart disease patients obtained by DGGE analysis showed a median richness of fungal species of 5 (range from 2 to 9) with a high interindividual variability (mean similarity 18.83%). For the first time, the presence of fungal components in atherosclerotic plaques has been demonstrated. Coronary atheromatous plaques harbour diverse and variable fungal communities suggesting a polymicrobial contribution to the chronic inflammatory aetiology.

Role of NOD2/CARD15 in coronary heart disease.

BACKGROUND: Bacterial DNA has been repeatedly detected in atheromatous lesions of coronary heart disease (CHD) patients. Phylogenetic signatures in the atheroma lesions that are similar to those of bacterial biofilms on human barrier organs, including the respiratory or gastrointestinal tract, raise the question of a defective barrier function in CHD. NOD2 plays a major role in defense against bacterial invasion. Genetic variation in the CARD15 gene, which encodes NOD2, was previously shown to result in a barrier defect that causes chronic inflammatory disorders (e.g. Crohn disease). In the present study, we investigated the possible involvement of NOD2/CARD15 in the pathology of CHD by i) analyzing the local expression of NOD2 in atherectomy versus healthy tissue (n = 5 each) using histochemical immunofluorescence and ii) by testing the three major functional CARD15 variants (R702W, G908R and 1007fs) for association with early-onset CHD in 900 German patients and 632 healthy controls. RESULTS: In atherectomy tissue of CHD patients, NOD2 was detected in inflammatory cells at the luminal sides of the lesions. However, the allele and genotype frequencies of the three major CARD15 polymorphisms did not differ between CHD patients and controls. CONCLUSION: The NOD2 up-regulation in atheroma lesions indicates an involvement of this protein in the pathology of CHD. Although NOD2 could be important in local immune response mechanisms, none of the analyzed CARD15 variants seem to play a significant role in the etiology of CHD.

Signal transducer of inflammation gp130 modulates atherosclerosis in mice and man.

Liver-derived acute phase proteins (APPs) emerged as powerful predictors of cardiovascular disease and cardiovascular events, but their functional role in atherosclerosis remains enigmatic. We report that the gp130 receptor, which is a key component of the inflammatory signaling pathway within hepatocytes, influences the risk of atherosclerosis in a hepatocyte-specific gp130 knockout. Mice on an atherosclerosis-prone genetic background exhibit less aortic atherosclerosis (P < 0.05) with decreased plaque macrophages (P < 0.01). Translating these findings into humans, we show that genetic variation within the human gp130 homologue, interleukin 6 signal transducer (IL6ST), is significantly associated with coronary artery disease (CAD; P < 0.05). We further show a significant association of atherosclerotic disease at the ostium of the coronary arteries (P < 0.005) as a clinically important and heritable subphenotype in a large sample of families with myocardial infarction (MI) and a second independent population-based cohort. Our results reveal a central role of a hepatocyte-specific, gp130-dependent acute phase reaction for plaque development in a murine model of atherosclerosis, and further implicate IL6ST as a genetic susceptibility factor for CAD and MI in humans. Thus, the acute phase reaction should be considered an important target for future drug development in the management of CAD.

Functional promoter polymorphism in the VKORC1 gene is no major genetic determinant for coronary heart disease in Northern Germans.

Recently, the C-allele of polymorphism rs2359612 (VKORC1: c.283+837C>T) in the VKORC1 gene has been reported to represent a major risk factor for coronary heart disease (CHD), stroke, and aortic dissection in Chinese patients. VKOR activity itself is the rate-limiting step in gamma-carboxylation of vitamin K-dependent coagulation factors (factors II, VII, IX, X, protein C, S, and Z) and proteins of calcium metabolism (matrix Gla protein and osteocalcin). Gamma-carboxylation is essential for the biological activity of these proteins that have been previously hypothesised to play a role in the pathogenesis of atherosclerosis. It was the objective of this study to analyse the VKORC1 genotype frequency in patients with CHD and controls from Northern Germany and to investigate the association of VKORC1 and CHD risk in patients with an European background. CHD patients (n = 901) and healthy controls (n = 521) were part of the PopGen biobank. Case and control samples were matched for ethnic and geographic origin, age and gender. After typing German CHD patients and control individuals, no evidence for a statistically significant association was detected between VKORC1 genotype and CHD phenotype. Also stratification for gender and myocardial infarction yielded no significant results. In conclusion, the discrepant association findings in Chinese and German populations may be explained by ethnic differences in genetic and perhaps environmental predisposition, modifying the polygenic CHD phenotype by interacting with VKORC1 variants and thus conferring disease susceptibility in some populations, but not in others.