Early-onset Coronary Artery Disease Research Articles

Gene–smoking interactions in multiple Rho-GTPase pathway genes in an early-onset coronary artery disease cohort

We performed a gene-smoking interaction analysis using families from an early-onset coronary artery disease cohort (GENECARD). This analysis was focused on validating and expanding results from previous studies implicating single nucleotide polymorphisms (SNPs) on chromosome 3 in smoking-mediated coronary artery disease. We analyzed 430 SNPs on chromosome 3 and identified 16 SNPs that showed a gene-smoking interaction at P < 0.05 using association in the presence of linkage--ordered subset analysis, a method that uses permutations of the data to empirically estimate the strength of the association signal. Seven of the 16 SNPs were in the Rho-GTPase pathway indicating a 1.87-fold enrichment for this pathway. A meta-analysis of gene-smoking interactions in three independent studies revealed that rs9289231 in KALRN had a Fisher's combined P value of 0.0017 for the interaction with smoking. In a gene-based meta-analysis KALRN had a P value of 0.026. Finally, a pathway-based analysis of the association results using WebGestalt revealed several enriched pathways including the regulation of the actin cytoskeleton pathway as defined by the Kyoto Encyclopedia of Genes and Genomes.

GW24-e1009 Lack of association of a common polymorphism of the endothelial lipase gene with early onset coronary artery disease in a Chinese Han population

ObjectivesEndothelial lipase (EL) is a novel member of the triglyceride (TG) lipase family. A growing body of evidence has indicated that EL gene polymorphism might contribute to the process of...

GW24-e3089 Association of HMW-total adiponectin ratio with early-onset coronary artery disease in a Chinese population

ObjectivesAdiponectin is an adipose-secreted protein that shows atheroprotective property and inverse relation with coronary artery disease (CAD). HMW adiponectin has been reported as an active form of adiponectin, however, whether...

Is CD36 gene polymorphism in region encoding lipid-binding domain associated with early onset CAD?

CD36 is a fatty acid translocase in striated muscle cells and cardiomyocytes. Some study suggested that alterations in CD36 gene may be associated with coronary artery disease (CAD) risk. The aim of the current study was to compare the frequency of CD36 variants in region encoding lipid-binding domain in Caucasian patients with early-onset CAD, no-CAD adult controls and neonates. The study group comprised 100 patients with early onset CAD. The genetic control groups were 306 infants and 40 no-CAD adults aged over 70years. Exons 4, 5 and 6 including fragments of flanking introns were studied using the denaturing high-performance liquid chromatography technique and direct sequencing. Changes detected in analyzed fragment of CD36: IVS3-6 T/C (rs3173798), IVS4-10 G/A (rs3211892), C311T (Thr104Ile, not described so far) in exon 5, G550A (Asp184Asn, rs138897347), C572T (Pro191Leu, rs143150225), G573A (Pro191Pro, rs5956) and A591T (Thr197Thr, rs141680676) in exon 6. No significant differences in the CD36 genotype, allele and haplotype frequencies were found between the three groups. Only borderline differences (p=0.066) were found between early onset CAD patients and newborns in the frequencies of 591T allele (2.00% vs 0.50%) and CGCGCGT haplotype (2.00% vs 0.50%) with both IVS3-6C and 591T variant alleles. In conclusion, CD36 variants: rs3173798, rs3211892, rs138897347, rs5956, rs143150225 rs141680676 and C311T do not seem to be involved in the risk of early-onset CAD in Caucasian population.

Effect of Positive Well-Being on Incidence of Symptomatic Coronary Artery Disease

Although negative emotions and psychiatric morbidity have often been found to increase incident coronary artery disease (CAD) risk, fewer studies have shown positive emotions to be protective against CAD; none have been performed in high-risk healthy populations, taking risk factors into account. Thus, we examined the effect of positive well-being on incident CAD in both a high-risk initially healthy population and a national probability sample. We screened healthy siblings of probands with documented early-onset CAD from 1985 to 2007 in the GeneSTAR (Genetic Study of Atherosclerosis Risk) population and examined sociodemographic data, risk factors, and positive well-being using the General Well-Being Schedule. We further classified siblings into high-, intermediate-, and low-risk strata according to the Framingham risk score and followed them for 5 to 25years. Siblings (n= 1,483) with greater baseline General Well-Being Schedule total scores were significantly less likely to develop CAD (hazard ratio 0.67, 95% confidence interval 0.58 to 0.79), independent of age, gender, race, and traditional risk factors. Protection was strongest in the high Framingham risk score stratum (hazard ratio 0.52, 95% confidence interval 0.30 to 0.90). The findings were replicated in the first National Health and Nutrition Examination Survey and Epidemiologic Follow-up Study (n= 5,992; hazard ratio 0.87, 95% confidence interval 0.83 to 0.93). In conclusion, positive well-being was associated with nearly a 1/3 reduction in CAD in a high-risk population with a positive family history, a nearly 50% reduction in incident CAD in the highest risk stratum in those with a positive family history, and a 13% reduction in incident CAD in a national probability sample, independent of the traditional CAD risk factors.

Relation of Subclinical Coronary Artery Atherosclerosis to Cerebral White Matter Disease in Healthy Subjects From Families With Early-Onset Coronary Artery Disease

White matter disease (WMD) of the brain is associated with incident stroke. Similarly, subclinical calcified coronary artery plaque has been associated with incident coronary artery disease (CAD) events. Although atherogenesis in both vascular beds may share some common mechanisms, the extent to which subclinical CAD is associated with WMD across age ranges in subjects with a family history of early-onset CAD remains unknown. We screened 405 apparently healthy participants in the Genetic Study of Atherosclerotic Risk for CAD risk factors and for the presence of noncalcified and calcified coronary plaque using dual-source multidetector cardiac computed tomographic angiography. The presence and volumes of WMD were assessed by 3-Tesla brain magnetic resonance imaging. Participants were 60% women, 36% African-American, mean age 51.6 ± 10.6 years. The overall prevalence of coronary plaque was 43.0%. Subjects with coronary plaque had significantly greater WMD volumes (median 1,222 mm³, interquartile range 448 to 3,871) compared with those without coronary plaque (median 551 mm³, interquartile range 105 to 1,523, p <0.001). In multivariate regression analysis, adjusting for age, gender, race, traditional risk factors, total brain volume, and intrafamilial correlations, the presence of coronary plaque was independently associated with WMD volume (p = 0.05). This study shows a significant association between WMD and noncalcified and calcified coronary plaque in healthy subjects, independent of age and risk factors. In conclusion, these findings support the premise of possible shared causal pathways in 2 vascular beds in families at increased risk for early-onset vascular disease.

AB1226 Leptin, adiponectin, resistin, visfatin serum levels and idiopathic recurrent pericarditis: A preliminary report

BackgroundIdiopathic acute recurrent pericarditis (IRAP) represents the most troublesome complication of acute pericarditis and is an autoimmune process (1). White adipose tissue produces more than 50 adipokines that participate in...

Two Chromosome 9p21 Haplotype Blocks Distinguish Between Coronary Artery Disease and Myocardial Infarction Risk

Variants at the 9p21 locus associate with the risk of coronary artery disease (CAD) or myocardial infarction (MI). However, atherosclerotic plaque deposition is distinct from MI (plaque rupture and thrombosis), and recent studies showed no association between these variants and MI in patients with preexisting CAD. We performed haplotype analysis at the 9p21 locus to test whether haplotypes at distinct linkage disequilibrium blocks predict these phenotypes. Using 24 single-nucleotide polymorphisms genotyped in white patients without diabetes mellitus, we reconstructed haplotypes at the 9p21 locus. Patients with angiograhic CAD/MI had ≥1 epicardial stenosis >50% (n=2352), whereas controls were asymptomatic and over the age of 60 years (n=2116). For CAD patients, regression models examined the association of haplotypes with initial age of symptomatic CAD, number of diseased vessels, and history of MI. In the case-control study, only haplotypes at 1 block tagged by rs1333049 associated with CAD more so than MI. These haplotypes also associated with early onset of CAD (β=-0.13; P=1.37×10(-4)) and disease severity (β=0.1823; P=0.006) but not with prevalent MI among patients with CAD. In contrast, haplotypes at another block tagged by rs518394 associated with prevalent MI (β=0.239; P=2.05×10(-4)), but remarkably these are inversely associated with disease severity (β=-0.196; P=0.003). This MI association was replicated in the Cleveland Clinic GeneBank premature CAD cohort (n=1385; β=0.207; P=0.019). Variants/haplotypes at 2 blocks are distinguished at 9p21; those at 1 block predispose to atherosclerosis, whereas those at the other predispose to MI among patients with preexisting CAD.

Smooth muscle hyperplasia due to loss of smooth muscle α-actin is driven by activation of focal adhesion kinase, altered p53 localization and increased levels of platelet-derived growth factor receptor-β

Mutations in ACTA2, encoding the smooth muscle cell (SMC)-specific isoform of α-actin (α-SMA), cause thoracic aortic aneurysms and dissections and occlusive vascular diseases, including early onset coronary artery disease and stroke. We have shown that occlusive arterial lesions in patients with heterozygous ACTA2 missense mutations show increased numbers of medial or neointimal SMCs. The contribution of SMC hyperplasia to these vascular diseases and the pathways responsible for linking disruption of α-SMA filaments to hyperplasia are unknown. Here, we show that the loss of Acta2 in mice recapitulates the SMC hyperplasia observed in ACTA2 mutant SMCs and determine the cellular pathways responsible for SMC hyperplasia. Acta2(-/-) mice showed increased neointimal formation following vascular injury in vivo, and SMCs explanted from these mice demonstrated increased proliferation and migration. Loss of α-SMA induced hyperplasia through focal adhesion (FA) rearrangement, FA kinase activation, re-localization of p53 from the nucleus to the cytoplasm and increased expression and ligand-independent activation of platelet-derived growth factor receptor beta (Pdgfr-β). Disruption of α-SMA in wild-type SMCs also induced similar cellular changes. Imatinib mesylate inhibited Pdgfr-β activation and Acta2(-/-) SMC proliferation in vitro and neointimal formation with vascular injury in vivo. Loss of α-SMA leads to SMC hyperplasia in vivo and in vitro through a mechanism involving FAK, p53 and Pdgfr-β, supporting the hypothesis that SMC hyperplasia contributes to occlusive lesions in patients with ACTA2 missense mutations.

Postmenopausal sex hormones: comparing apples and pears

Postmenopausal sex hormones: comparing apples and pears

Multi-allelic haplotype association identifies novel information different from single-SNP analysis: A new protective haplotype in the LRP8 gene is against familial and early-onset CAD and MI

Our previous studies identified a functional SNP, R952Q in the LRP8 gene, that was associated with increased platelet activation and familial and early-onset coronary artery disease (CAD) and myocardial infarction (MI) in American and Italian Caucasian populations. In this study, we analyzed four additional SNPs near R952Q (rs7546246, rs2297660, rs3737983, rs5177) to identify a specific LRP8 SNP haplotype that is associated with familial and early-onset CAD and MI. We employed a case–control association design involving 381 premature CAD and MI probands and 560 controls in GeneQuest, 441 individuals from 22 large pedigrees in GeneQuest II, and 248 MI patients with family history and 308 controls in an Italian cohort. Like R952Q, LRP8 SNPs rs7546246, rs2297660, rs3737983, and rs5177 were significantly associated with early-onset CAD/MI in both population-based and family-based association studies in GeneQuest. The results were replicated in the GeneQuest II family-based population and the Italian population. We then carried out a haplotype analysis for all five SNPs including R952Q. One common haplotype (TCCGC) was significantly associated with CAD (P=4.0×10−11) and MI (P=6.5×10−12) in GeneQuest with odds ratios of 0.53 and 0.42, respectively. The results were replicated in the Italian cohort (P=0.004, OR=0.71). The sib-TDT analysis also showed significant association between the TCCGC haplotype and CAD in GeneQuest II (P=0.001). These results suggest that a common LRP8 haplotype TCCGC confers a significant protective effect on the development of familial, early-onset CAD and/or MI.

LRP6 Enhances Glucose Metabolism by Promoting TCF7L2-Dependent Insulin Receptor Expression and IGF Receptor Stabilization in Humans

Common genetic variations in Wnt signaling genes have been associated with metabolic syndrome and diabetes by mechanisms that are poorly understood. A rare nonconservative mutation in Wnt coreceptor LRP6 (LRP6(R611C)) has been shown to underlie autosomal dominant early onset coronary artery disease, type 2 diabetes, and metabolic syndrome. We examined the interplay between Wnt and insulin signaling pathways in skeletal muscle and skin fibroblasts of healthy nondiabetic LRP6(R611C) mutation carriers. LRP6 mutation carriers exhibited hyperinsulinemia and reduced insulin sensitivity compared to noncarrier relatives in response to oral glucose ingestion, which correlated with a significant decline in tissue expression of the insulin receptor and insulin signaling activity. Further investigations showed that the LRP6(R611C) mutation diminishes TCF7L2-dependent transcription of the IR while it increases the stability of IGFR and enhances mTORC1 activity. These findings identify the Wnt/LRP6/TCF7L2 axis as a regulator of glucose metabolism and a potential therapeutic target for insulin resistance.

Extradural hematoma surgery in a child with Hutchinson-Gilford progeria syndrome: Perioperative concerns

Hutchinson–Gilford progeria syndrome (HGPS) is a very rare genetic disorder characterized by premature ageing, severe growth failure, and very early onset atherosclerosis. Psychologically and emotionally child-like, these patients suffer from physiological changes of old age. Early and progressive atherosclerosis of intra-cranial vessels in HGPS patients, along with a thin skin and fragile vessels, make these patients susceptible to intra-cranial hematomas following relatively trivial injuries and to severe intra-cranial disease. Anesthetizing HGPS patients for surgery can be challenging due to the presence of a possible difficult airway, multi-system derangements, and associated skin, bone and joint disease. We report here one such child with HGPS who underwent craniotomy and evacuation of an extradural hematoma that developed after minor head trauma. Securing his airway during surgery was difficult.

Frequency of MTHFR G1793A polymorphism in individuals with early coronary artery disease: cross-sectional study.

Atherosclerotic disease is the leading cause of death in Brazil. It is a complex disease and its prevention involves identification and control of risk factors. Moderately increased plasma homocysteine concentration (hyperhomocysteinemia) has been considered to be a risk factor for several vascular diseases. Mutations in the methylenetetrahydrofolate reductase (MTHFR) enzyme, which is involved in homocysteine metabolism, have been investigated as potential vascular disease risk factors. G1793A polymorphism was described in 2002 and there are few studies analyzing its involvement in diseases. The objective of this study was to investigate the prevalence of G1793A polymorphism in subjects with early coronary artery disease (CAD). Cross-sectional study with control group conducted at a private cardiology clinic and a molecular biology laboratory (Universidade do Vale do Itajaí). We studied 74 early-onset CAD+ patients and 40 CAD- individuals with normal angiography results. DNA was extracted from blood samples. Molecular data were obtained via PCR/RFLP and agarose gel electrophoresis. The occurrence of G1793A heterozygotes was similar in the control (5%) and test (6.25%) groups, thus showing that in the population studied there was no correlation between the marker and occurrences of early CAD. There was also no association between the polymorphism and the risk factors for atherosclerosis. The frequency of the 1793A allele in the test group (3.4%) was similar to what was found in the control individuals (2.5%). There was no correlation between G1793A polymorphism and occurrences of early CAD in this population.

Risk Factors for Subclinical Atherosclerosis in Diabetic and Obese Children

Background. Increased carotid intima-media thickness (cIMT) is considered a marker of early-onset atherosclerosis and it seems to predict cardiovascular events both in obese and diabetic subjects. We aimed to evaluate early signs of atherosclerosis and investigate for predisposing factors in children and adolescents affected by type 1 diabetes (T1DM) or obesity, comparing them with healthy controls.Methods. Out of 71 enrolled subjects (mean age 12.8 ± 2.3 years), 26 had T1DM and 24 were obese, while 21 age- and sex-matched subjects acted as controls. cIMT was measured using standardized methods. Serum glucose, insulin, cholesterol, triglycerides and C-reactive protein levels were evaluated. An oral glucose tolerance test (OGTT) was performed in obese subjects.Results. Diabetic and obese individuals showed higher cIMT mean values than healthy controls (p<0.005). cIMT of the three examined segments correlated positively with fasting glucose levels and negatively with units of insulin/kg/day administered in T1DM individuals. A positive correlation between insulin levels (basal and after oral glucose load) and cIMT of common, internal and external carotid artery was found in obese subjects (p<0.03). High density cholesterol levels represented a protective factor for cIMT in this latter group of the study population.Conclusions. Our findings show that cIMT correlates with high insulin levels (a sign of insulin resistance) in obese patients and with high fasting glucose levels (a sign of relative insulin deficiency) in T1DM subjects, confirming the need of reducing hyperinsulinism and monitoring blood glucose levels in these subjects to prevent atherosclerosis.

Association of CD36 gene polymorphisms with echo- and electrocardiographic parameters in patients with early onset coronary artery disease

IntroductionCD36 plays an important role in long-chain fatty acid homeostasis in skeletal muscle and the myocardium. CD36 deficiency may lead to reduced myocardial uptake of long-chain fatty acid. Therefore, different mutations of the CD36 gene may contribute to the clinical heterogeneity of cardiac hypertrophy.Material and methodsThe objective of the study was to investigate whether there is an association between the sequence changes in CD36 and echocardiographic and electrocardiographic parameters in Caucasian patients with early onset coronary artery disease. The study group comprised 100 patients. Electrocardiography and echocardiography were performed in all patients. Amplicons of exons 4 to 6 including fragments of introns were studied using the denaturing high-performance liquid chromatography technique.ResultsIVS3-6TC (rs3173798) heterozygotes had impaired left ventricle diastolic function. 573GA heterozygotes (rs5956) had higher frequency of pseudonormal left ventricular diastolic function and it was confirmed by the increase in wave A’ in the tissue Doppler. 591AT genotype was associated with borderline higher posterior wall end-diastolic thickness and lower E/A ratio. These results are consistent with electrocardiography parameters which could reflect left ventricular hypertrophy (higher RV5(6) and RV5(6) + SV1(2) parameters, depressed ST segments and tendency to longer Qtc II interval) in 591AT heterozygotes.ConclusionsDetected variant alleles of CD36 may be associated with features of left ventricular hypertrophy and impaired diastolic function.

Endothelial dysfunction, arterial stiffening, and intima-media thickening in large arteries from HIV-1 transgenic mice.

HIV patients on highly active antiretroviral therapy (HAART) exhibit elevated incidence of cardiovascular disease (CVD), including a higher risk of myocardial infarction and prevalence of atherosclerotic lesions, as well as increases in markers of subclinical atherosclerosis including increased carotid artery intima-media thickness (c-IMT), increased arterial stiffness, and impaired flow-mediated dilation. Both HAART and HIV-infection are independent risk factors for atherosclerosis and myocardial infarction. Studies implicate the HIV proteins tat, gp120, vpu, and nef in early on-set atherosclerosis. The objective of this study was to quantify the role of expression of HIV-1 proteins on the vascular function, biomechanics, and geometry of common carotid arteries and aortas. This study employed NL4-3Δ gag/pol transgenic mice (HIV-Tg), which contain the genetic sequence for the HIV-1 proteins env, tat, nef, rev, vif, vpr, and vpu but lacks the gag and pol genes and reports that HIV-Tg mice have impaired aortic endothelial function, increased c-IMT, and increased arterial stiffness. Further, HIV-Tg arteries show decreased elastin content, increased cathepsin K and cathepsin S activity, and increased mechanical residual stress. Thus, mice that express HIV proteins exhibit pre-clinical markers of atherosclerosis and these markers correlate with changes in markers of vascular remodeling. These findings are consistent with the hypothesis that HIV-proteins, independent of HAART treatment or HIV infection, could play a role in of the development of CVD.

Abstract 19364: Coronary Plaque Characteristics by Age and Sex in Healthy Individuals with a Family History of Early-Onset Coronary Artery Disease

Background: Although calcified coronary plaque (CCP) increases with age and is more prevalent in males, the extent to which noncalcified plaque (NCP) is present across the age range of both sexes is unknown. This has important implications for primary prevention guidelines, particularly in high risk populations, since NCP is a putative immediate precursor for coronary artery disease (CAD) events. We thus examined total coronary plaque (TCP), CCP, and NCP distributions in healthy male and female first degree relatives of persons with early-onset CAD. Methods: Participants in GeneSTAR (N=561), mean age 51.5 ± 10.8 years, range 30 to 75 years, 58% female, were screened for coronary plaque using 256 multidetector dual-source CT angiography. Segmental plaque volumes (mm3) were quantified using an automated well-validated proprietary method and summed for CCP and NCP. TCP was calculated from CCP+NCP. Results: Males had a higher prevalence of any coronary plaque compared to females, (58.1% vs 36.7% respectively, p&lt;0.0001); plaque prevalence increased significantly with age (Table). However, females more often had only NCP than males, (17.6% vs 8.9%, p= 0.11). CCP and NCP volumes both increased with age in both sexes, but NCP accounted for more than half of TPV in both sexes at all ages; NCP represented more than 80% of TPV in subjects &lt;55 years of age. Conclusion: The majority of TPV was noncalcified plaque in this healthy high risk population, particularly in females and in males &lt;55 years old. Thus, conditioning aggressive primary prevention on traditional coronary calcium scoring algorithms, may obviate appropriate risk reduction interventions in young persons with a family history of early onset-CAD. Table: Sex-specific noncalcified and calcified coronary plaque volumes by age group (median [IQR])

Inflammatory Dilated Cardiomyopathy in Abcg5-deficient Mice

Dilated cardiomyopathy (DCM) in A/J mice homozygous for the spontaneous thrombocytopenia and cardiomyopathy (trac) mutation results from a single base pair change in the Abcg5 gene. A similar mutation in humans causes sitosterolemia with high plant sterol levels, hypercholesterolemia, and early onset atherosclerosis. Analyses of CD3+ and Mac-3+ cells and stainable collagen in hearts showed inflammation and myocyte degeneration in A/J-trac/trac mice beginning postweaning and progressed to marked dilative and fibrosing cardiomyopathy by 140 days. Transmission electron microscopy (TEM) demonstrated myocyte vacuoles consistent with swollen endoplasmic reticulum (ER). Myocytes with cytoplasmic glycogen and irregular actinomyosin filament bundles formed mature intercalated disks with normal myocytes suggesting myocyte repair. A/J-trac/trac mice fed lifelong phytosterol-free diets did not develop cardiomyopathy. BALB/cByJ-trac/trac mice had lesser inflammatory infiltrates and later onset DCM. BALB/cByJ-trac/trac mice changed from normal to phytosterol-free diets had lesser T cell infiltrates but persistent monocyte infiltrates and equivalent fibrosis to mice on normal diets. B- and T-cell-deficient BALB/cBy-Rag1(null) trac/trac mice fed normal diets did not develop inflammatory infiltrates or DCM. We conclude that the trac/trac mouse has many features of inflammatory DCM and that the reversibility of myocardial T cell infiltration provides a novel model for investigating the progression of myocardial fibrosis.

Protective effect of Tulbaghia violacea Harv. on aortic pathology, tissue antioxidant enzymes and liver damage in diet-induced atherosclerotic rats.

The protective effect Tulbaghia violacea rhizomes (TVR) against derangements in serum lipid profile, tissue antioxidant enzyme depletion, endothelium dysfunction and histopathological changes in the aorta and liver of rats fed with an atherosclerogenic (Ath) diet (4% cholesterol, 1% cholic acid and 0.5% thiouracil) was investigated in this study. Co-treatment with the TVR extracts (250 and 500 mg/kg body weight for two weeks significantly (p < 0.05) protected against elevated serum triglyceride (TG), total cholesterol (TC), LDL-cholesterol, VLDL-cholesterol and decreased HDL-cholesterol in a dosedependent manner when compared with the atherogenic control. The extracts also reduced (p < 0.05) elevated thiobabutric reacting substance (TBARS) and reversed endothelial dysfunction parameters (fibrinogen and total NO levels) and tissue antioxidant enzyme activities to near normal. The protective ability of the extract was confirmed by the significant (p < 0.05) reduction in the activities of serum markers of liver (LDH, AST, ALT, ALP, bilirubin) and kidney damage (creatinine and bilirubin) in extract-treated groups compared with the atherogenic control group. Also, histopathology evaluations of aorta sections revealed that the extracts protected against the development of fatty streak plaques (aorta) and fatty changes in hepatocytes. The observed activities of the extracts compared favorably with standard drug atorvastatin. Our study thus showed that the methanolic extract of TVR could protect against the early onset of atherosclerosis.