Explore the vast range of titles available.

Coronary artery disease (CAD) is the leading cause of human morbidity and mortality worldwide, underscoring the need to improve diagnostic strategies. Platelets play a major role, not only in the process of acute thrombosis during plaque rupture, but also in the formation of atherosclerosis itself. MicroRNAs are endogenous small non-coding RNAs that control gene expression and are expressed in a tissue and disease-specific manner. Therefore they have been proposed to be useful biomarkers. It remains unknown whether differences in miRNA expression levels in platelets can be found between patients with premature CAD and healthy controls. In this case-control study we measured relative expression levels of platelet miRNAs using microarrays from 12 patients with premature CAD and 12 age- and sex-matched healthy controls. Six platelet microRNAs were significantly upregulated (miR340*, miR451, miR454*, miR545:9.1. miR615-5p and miR624*) and one miRNA (miR1280) was significantly downregulated in patients with CAD as compared to healthy controls. To validate these results, we measured the expression levels of these candidate miRNAs by qRT-PCR in platelets of individuals from two independent cohorts; validation cohort I consisted of 40 patients with premature CAD and 40 healthy controls and validation cohort II consisted of 27 patients with artery disease and 40 healthy relatives. MiR340* and miR624* were confirmed to be upregulated in patients with CAD as compared to healthy controls in both validation cohorts. Two miRNAs in platelets are significantly upregulated in patients with CAD as compared to healthy controls. Whether the two identified miRNAs can be used as biomarkers and whether they are cause or consequence of the disease remains to be elucidated in a larger prospective study.

Turning genetic discoveries identified in genome-wide association (GWA) studies into biological mechanisms is an important challenge in human genetics. Many GWA signals map outside exons, suggesting that the associated variants may lie within regulatory regions. We applied the formaldehyde-assisted isolation of regulatory elements (FAIRE) method in a megakaryocytic and an erythroblastoid cell line to map active regulatory elements at known loci associated with hematological quantitative traits, coronary artery disease, and myocardial infarction. We showed that the two cell types exhibit distinct patterns of open chromatin and that cell-specific open chromatin can guide the finding of functional variants. We identified an open chromatin region at chromosome 7q22.3 in megakaryocytes but not erythroblasts, which harbors the common non-coding sequence variant rs342293 known to be associated with platelet volume and function. Resequencing of this open chromatin region in 643 individuals provided strong evidence that rs342293 is the only putative causative variant in this region. We demonstrated that the C- and G-alleles differentially bind the transcription factor EVI1 affecting PIK3CG gene expression in platelets and macrophages. A protein-protein interaction network including up- and down-regulated genes in Pik3cg knockout mice indicated that PIK3CG is associated with gene pathways with an established role in platelet membrane biogenesis and thrombus formation. Thus, rs342293 is the functional common variant at this locus; to the best of our knowledge this is the first such variant to be elucidated among the known platelet quantitative trait loci (QTLs). Our data suggested a molecular mechanism by which a non-coding GWA index SNP modulates platelet phenotype.

Mark McCarthy, Michael Boehnke, Andrew Morris and colleagues perform large-scale association analyses using the Metabochip to gain insights into the genetic architecture of type 2 diabetes. They report several new susceptibility loci, including two that show sex-differentiated effects on disease risk. To extend understanding of the genetic architecture and molecular basis of type 2 diabetes (T2D), we conducted a meta-analysis of genetic variants on the Metabochip, including 34,840 cases and 114,981 controls, overwhelmingly of European descent. We identified ten previously unreported T2D susceptibility loci, including two showing sex-differentiated association. Genome-wide analyses of these data are consistent with a long tail of additional common variant loci explaining much of the variation in susceptibility to T2D. Exploration of the enlarged set of susceptibility loci implicates several processes, including CREBBP-related transcription, adipocytokine signaling and cell cycle regulation, in diabetes pathogenesis.

The burden of cardiovascular disease (CVD) cannot be fully addressed by therapy targeting known pathophysiological pathways. Even with stringent control of all risk factors CVD events are only diminished by half. A number of additional pathways probably play a role in the development of CVD and might serve as novel therapeutic targets. Genome wide expression studies represent a powerful tool to identify such novel pathways. We compared the expression profiles in monocytes from twenty two young male patients with premature familial CAD with those from controls matched for age, sex and smoking status, without a family history of CVD. Since all patients were on statins and aspirin treatment, potentially affecting the expression of genes in monocytes, twelve controls were subsequently treated with simvastatin and aspirin for 6 and 2 weeks, respectively. By whole genome expression arrays six genes were identified to have differential expression in the monocytes of patients versus controls; ABCA1, ABCG1 and RGS1 were downregulated in patients, whereas ADRB2, FOLR3 and GSTM1 were upregulated. Differential expression of all genes, apart from GSTM1, was confirmed by qPCR. Aspirin and statins altered gene expression of ABCG1 and ADBR2. All finding were validated in a second group of twenty four patients and controls. Differential expression of ABCA1, RSG1 and ADBR2 was replicated. In conclusion, we identified these 3 genes to be expressed differently in CAD cases which might play a role in the pathogenesis of atherosclerotic vascular disease.

Persistent inflammation has been proposed to contribute to various stages in the pathogenesis of cardiovascular disease. Interleukin-6 receptor (IL6R) signalling propagates downstream inflammation cascades. To assess whether this pathway is causally relevant to coronary heart disease, we studied a functional genetic variant known to affect IL6R signalling. In a collaborative meta-analysis, we studied Asp358Ala (rs2228145) in IL6R in relation to a panel of conventional risk factors and inflammation biomarkers in 125 222 participants. We also compared the frequency of Asp358Ala in 51 441 patients with coronary heart disease and in 136 226 controls. To gain insight into possible mechanisms, we assessed Asp358Ala in relation to localised gene expression and to postlipopolysaccharide stimulation of interleukin 6. The minor allele frequency of Asp358Ala was 39%. Asp358Ala was not associated with lipid concentrations, blood pressure, adiposity, dysglycaemia, or smoking (p value for association per minor allele ≥0·04 for each). By contrast, for every copy of 358Ala inherited, mean concentration of IL6R increased by 34·3% (95% CI 30·4–38·2) and of interleukin 6 by 14·6% (10·7–18·4), and mean concentration of C-reactive protein was reduced by 7·5% (5·9–9·1) and of fibrinogen by 1·0% (0·7–1·3). For every copy of 358Ala inherited, risk of coronary heart disease was reduced by 3·4% (1·8–5·0). Asp358Ala was not related to IL6R mRNA levels or interleukin-6 production in monocytes. Large-scale human genetic and biomarker data are consistent with a causal association between IL6R-related pathways and coronary heart disease. British Heart Foundation; UK Medical Research Council; UK National Institute of Health Research, Cambridge Biomedical Research Centre; BUPA Foundation.

In a 2-year clinical trial, the addition of ezetimibe to simvastatin had no effect on the progression of atherosclerosis, as measured by carotid-artery intima–media thickness, despite the additional lowering of levels of low-density lipoprotein cholesterol and C-reactive protein by ezetimibe when added to simvastatin. However, the study was not powered to assess clinical end points. The addition of ezetimibe to simvastatin had no effect on the progression of atherosclerosis, as measured by carotid-artery intima–media thickness, despite the additional lowering of levels of low-density lipoprotein cholesterol and C-reactive protein. A reduction in levels of low-density lipoprotein (LDL) cholesterol constitutes one of the cornerstones in the prevention of cardiovascular disease. In recent trials comparing various statins or the same statin at various doses, aggressive therapy to lower LDL cholesterol levels was associated with a reduction in rates of cardiovascular events. 1 – 4 However, administration of the highest approved statin dose offers only limited additional lowering of LDL cholesterol at the expense of an increased incidence of side effects. 5 Therefore, novel compounds that further reduce LDL cholesterol levels when added to statin therapy are of interest. A recently introduced compound, ezetimibe, selectively . . .

It is widely accepted that atherosclerosis and inflammation are intimately linked. Monocytes play a key role in both of these processes and we hypothesized that activation of inflammatory pathways in monocytes would lead to, among others, proatherogenic changes in the monocyte transcriptome. Such differentially expressed genes in circulating monocytes would be strong candidates for further investigation in disease association studies. Endotoxin, lipopolysaccharide (LPS), or saline control was infused in healthy volunteers. Monocyte RNA was isolated, processed and hybridized to Hver 2.1.1 spotted cDNA microarrays. Differential expression of key genes was confirmed by RT-PCR and results were compared to in vitro data obtained by our group to identify candidate genes. All subjects who received LPS experienced the anticipated clinical response indicating successful stimulation. One hour after LPS infusion, 11 genes were identified as being differentially expressed; 1 down regulated and 10 up regulated. Four hours after LPS infusion, 28 genes were identified as being differentially expressed; 3 being down regulated and 25 up regulated. No genes were significantly differentially expressed following saline infusion. Comparison with results obtained in in vitro experiments lead to the identification of 6 strong candidate genes (BATF, BID, C3aR1, IL1RN, SEC61B and SLC43A3) In vivo endotoxin exposure of healthy individuals resulted in the identification of several candidate genes through which systemic inflammation links to atherosclerosis.

ObjectiveThe value of a family history for coronary heart disease (CHD) in addition to established cardiovascular risk factors in predicting an individual's risk of CHD is unclear. In the European Prospective Investigation of Cancer (EPIC)-Norfolk cohort, the authors tested whether adding family history of premature CHD in first-degree relatives improves risk prediction compared with the Framingham risk score (FRS) alone.Methods and resultsThis study comprised 10 288 men and 12 553 women aged 40–79 years participating in the EPIC-Norfolk cohort who were followed for a mean of 10.9±2.1 years (mean±SD). The authors computed the FRS as well as a modified score taking into account family history of premature CHD. A family history of CHD was indeed associated with an increased risk of future CHD, independent of established risk factors (FRS-adjusted HR of 1.74 (95% CI 1.56 to 1.95) for family history of premature CHD). However, adding family history of CHD to the FRS resulted in a negative net reclassification of 2%. In the subgroup of individuals estimated to be at intermediate risk, family history of premature CHD resulted in an increase in net reclassification of 2%. The sensitivity increased with 0.4%, and the specificity decreased 0.8%.ConclusionAlthough family history of CHD was an independent risk factor of future CHD, its use did not improve classification of individuals into clinically relevant risk categories based on the FRS. Among study participants at intermediate risk of CHD, adding family history of premature CHD resulted in, at best, a modest improvement in reclassification of individuals into a more accurate risk category.

Atherosclerosis is a common multifactorial disease resulting from an interaction between susceptibility genes and environmental factors. The causative genes that contribute to atherosclerosis are elusive. Based on recent findings with a Wistar rat model, we speculated that the gamma-secretase pathway may be associated with atherosclerosis. We have tested for association of premature coronary atherosclerosis with a non-synonymous single-nucleotide polymorphism (SNP) in the gamma-secretase component APH1B (Phe217Leu; rs1047552), a SNP previously linked to Alzheimer's disease. Analysis of a Dutch Caucasian cohort (780 cases; 1414 controls) showed a higher prevalence of the risk allele in the patients (odds ratio (OR) = 1.35), albeit not statistically different from the control population. Intriguingly, after gender stratification, the difference was significant in males (OR = 1.63; p = 0.033), but not in females (OR = 0.50; p = 0.20). Since Phe217Leu-mutated APH1B showed reduced gamma-secretase activity in mouse embryonic fibroblasts, the genetic variation is likely functional. We conclude that, in a male-specific manner, disturbed gamma-secretase signalling may play a role in the susceptibility for premature coronary atherosclerosis.

We tested the hypothesis that an increase in spontaneous aggregability of platelets in vitro predicts mortality and coronary events in patients who have survived a recent myocardial infarction. A cohort of 149 survivors of infarction entered our study three months after the index infarction and was followed for five years. At entry and at intervals of six months, spontaneous platelet aggregation (SPA) was tested and graded as positive (aggregation within 10 minutes), intermediate (aggregation after 10 to 20 minutes), or negative (no aggregation within 20 minutes). During follow-up, 6.4 percent (6 of 94) of the patients in the SPA-negative group died, as compared with 10.3 percent (3 of 29) in the SPA-intermediate group and 34.6 percent (9 of 26) in the SPA-positive group. As compared with the SPA-negative group, the SPA-intermediate group had a relative risk of death of 1.6 (95 percent confidence interval, 0.5 to 5.5) and the SPA-positive group had a risk of 5.4 (95 percent confidence interval, 2.2 to 13.4). At least one cardiac event (cardiac death or recurrent nonfatal myocardial infarction) occurred in 14.9 percent (14 of 94 patients) of the SPA-negative group, 24.1 percent (7 of 29) of the SPA-intermediate group, and 46.2 percent (12 of 26) of the SPA-positive group. A positive test result continued to have prognostic value throughout the five-year study. We conclude that spontaneous platelet aggregation in vitro is a useful biologic marker for the prediction of coronary events and mortality in this low-risk group of survivors of a myocardial infarction. A causal relation is suggested but not proved by our study. (N Engl J Med 1990; 322:1549–54.) PLATELETS have an important role in atherosclerosis and its complications, such as acute coronary ischemia. 1 2 3 4 The pathophysiologic mechanism by which platelets contribute to the acute manifestations of coronary artery disease is not fully understood. A causal role of platelet hyperreactivity or of local platelet activation in an acute coronary event has been suggested but never proved. 5 Platelet products in plasma (beta-thromboglobulin, thromboxane, and platelet factor 4) have been measured to determine platelet activation in patients with coronary artery disease. 6 7 8 9 The results of these tests remain controversial and difficult to interpret. It has not yet been possible to select a platelet-function . . .