Cluster Alignments and Ellipticities in LCDM Cosmology

The ellipticities and alignments of clusters of galaxies, and their evolution with redshift, are examined in the context of a Lambda-dominated cold dark matter cosmology. We use a large-scale, high-resolution N-body simulation to model the matter distribution in a light cone containing ~10^6 clusters out to redshifts of z=3. Cluster ellipticities are determined as a function of mass, radius, and redshift, both in 3D and in projection. We find strong cluster ellipticities: the mean ellipticity increases with redshift from 0.3 at z=0 to 0.5 at z=3, for both 3D and 2D ellipticities; the evolution is well-fit by e=0.33+0.05z. The ellipticities increase with cluster mass and with cluster radius; the main cluster body is more elliptical than the cluster cores, but the increase of ellipticities with redshift is preserved. Using the fitted cluster ellipsoids, we determine the alignment of clusters as a function of their separation. We find strong alignment of clusters for separations <100 Mpc/h; the alignment increases with decreasing separation and with increasing redshift. The evolution of clusters from highly aligned and elongated systems at early times to lower alignment and elongation at present reflects the hierarchical and filamentary nature of structure formation. These measures of cluster ellipticity and alignment will provide a new test of the current cosmological model when compared with upcoming cluster surveys.Comment: 29 pages including 13 figures, to appear in ApJ Jan. 2005 (corrected typos, added reference

POLYMORPHISMS IN THE SERUM- AND GLUCOCORTICOID-INDUCIBLE KINASE 1 GENE ARE ASSOCIATED WITH BLOOD PRESSURE AND RENIN RESPONSE TO DIETARY SALT INTAKE

Serum- and glucocorticoid-inducible kinase 1 (SGK1) plays a central role in epithelial sodium channel (ENaC)-dependent Na+ transport in the distal nephron. We hypothesized that SGK1 gene variants may contribute to the effect of dietary salt intake on BP in humans with hypertension, and consequentially influence renin-angiotensin-aldosterone (RAA) system activity. Our study population included 421 hypertensive Caucasian participants of the HyperPath group who had completed a dietary salt protocol with measurement of BP and RAA system activity. Three SGK1 tagging single nucleotide polymorphisms (SNPs) from the HapMap CEU population captured the genetic variation in the SGK1 region. Assuming an additive genetic model, two SNPs (rs2758151 and rs9402571) were associated with BP and plasma renin activity (PRA) effects of dietary salt intake. Major alleles were associated with higher systolic BP on high salt and decreased PRA on low salt. In contrast, low salt neutralized genotype differences. Similar, non-significant trends were observed in a normotensive population (N=152). Genotype was also associated with two salt-sensitive subtypes of hypertension. SGK1 genetic variants are associated with salt sensitivity of BP and PRA in human hypertension. Genotype status at these SGK1 variants may identify individuals prone to salt-sensitive hypertension

Do inflammation and procoagulation biomarkers contribute to the metabolic syndrome cluster?

<p>Abstract</p> <p>Context</p> <p>The metabolic syndrome (MetS), in addition to its lipid, metabolic, and anthropomorphic characteristics, is associated with a prothrombotic and the proinflammatory state. However, the relationship of inflammatory biomarkers to MetS is not clear.</p> <p>Objective</p> <p>To study the association between a group of thrombotic and inflammatory biomarkers and the MetS.</p> <p>Methods</p> <p>Ten conventional MetS risk variables and ten biomarkers were analyzed. Correlations, factor analysis, hexagonal binning, and regression of each biomarker with the National Cholesterol Education Program (NCEP) MetS categories were performed in the Family Heart Study (n = 2,762).</p> <p>Results</p> <p>Subjects in the top 75% quartile for plasminogen activator inhibitor-1 (PAI1) had a 6.9 CI95 [4.2–11.2] greater odds (p < 0.0001) of being classified with the NCEP MetS. Significant associations of the corresponding top 75% quartile to MetS were identified for monocyte chemotactic protein 1 (MCP1, OR = 2.19), C-reactive protein (CRP, OR = 1.89), interleukin-6 (IL6, OR = 2.11), sICAM1 (OR = 1.61), and fibrinogen (OR = 1.86). PAI1 correlated significantly with all obesity and dyslipidemia variables. CRP had a high correlation with serum amyloid A (0.6) and IL6 (0.51), and a significant correlation with fibrinogen (0.46). Ten conventional quantitative risk factors were utilized to perform multivariate factor analysis. Individual inclusion, in this analysis of each biomarker, showed that, PAI1, CRP, IL6, and fibrinogen were the most important biomarkers that clustered with the MetS latent factors.</p> <p>Conclusion</p> <p>PAI1 is an important risk factor for MetS. It correlates significantly with most of the variables studied, clusters in two latent factors related to obesity and lipids, and demonstrates the greatest relative odds of the 10 biomarkers studied with respect to the MetS. Three other biomarkers, CRP, IL6, and fibrinogen associate also importantly with the MetS cluster. These 4 biomarkers can contribute in the MetS risk assessment.</p

Identification of a pleiotropic locus on chromosome 7q for a composite left ventricular wall thickness factor and body mass index: the HyperGEN Study

<p>Abstract</p> <p>Background</p> <p>Left ventricular (LV) mass and wall thickness are closely associated with measures of body size and blood pressure and also correlated with systolic and diastolic function, suggesting a contribution of common physiologic mechanisms, including pleiotropic genes, to their covariation.</p> <p>Methods</p> <p>Doppler echocardiography was performed in 434 African-American (1344 individuals) and 284 white families (1119 individuals). We conducted a genome-wide linkage scan for LV mass, LV structure and function, and composite factors derived from a factor analysis of LV structure and function in the HyperGEN Study population.</p> <p>Results</p> <p>Factor analysis identified (i) a LV wall thickness factor correlated strongly with interventricular septal thickness (IVSTd) and posterior wall thickness (PWTd) and (ii) a LV diastolic filling factor strongly correlated with early and atrial phase peak transmitral filling velocities. The LV phenotypes and composite factor scores were analyzed in multipoint variance components linkage model implemented in SOLAR with 387 microsatellite markers. In whites, the two highest LODs were 3.42 for LV atrial phase peak filling velocity at 144 cM on chromosome 1 and 3.12 for the LV wall thickness factor at 160 cM on chromosome 7. The peak LODs of the component traits (IVSTd and PWTd) clustered at the same region as the composite factor. Adjusting the factor score for body mass index (BMI) substantially reduced the peak LOD at this region (LOD = 1.92). Bivariate linkage analysis of the composite factor with BMI improved LOD to 3.42 at 158 cM. Also in whites, suggestive linkage was observed on chromosomes 2 and 4 for LV mass, chromosomes 3, 5, 10, and 17 for LV atrial phase peak filling velocity, and chromosome 10 for LV diastolic filling factor. In African Americans, suggestive linkage was observed on chromosome 12 for LV mass, chromosome 21 for IVSTd, and chromosome 3 for LV internal diameter at end-diastole.</p> <p>Conclusion</p> <p>Our study suggests that a region on chromosome 7 contains pleiotropic genes contributing to the variations of both LV wall thickness and BMI in whites.</p

Salt restriction lowers blood pressure at rest and during exercise without altering peripheral hemodynamics in hypertensive individuals

Dietary salt restriction is a well-established approach to lower blood pressure and reduce cardiovascular disease risk in hypertensive individuals. However, little is currently known regarding the effects of salt restriction on central and peripheral hemodynamic responses to exercise in those with hypertension. Therefore, this study sought to determine the impact of salt restriction on the central and peripheral hemodynamic responses to static-intermittent handgrip (HG) and dynamic single-leg knee extension (KE) exercise in individuals with hypertension. Twenty-two subjects (14 men and 8 women, 51 ± 10 yr, 173 ± 11 cm, 99 ± 23 kg) forewent their antihypertensive medication use for at least 2 wk before embarking on a 5-day liberal salt (LS: 200 mmol/day) diet followed by a 5-day restricted salt (RS: 10 mmol/day) diet. Subjects were studied at rest and during static intermittent HG exercise at 15, 30, and 45% of maximal voluntary contraction and KE exercise at 40, 60, and 80% of maximum KE work rate. Salt restriction lowered resting systolic blood pressure (supine: −12 ± 12 mmHg, seated: −17 ± 12 mmHg) and diastolic blood pressure (supine: −3 ± 9 mmHg, seated: −5 ± 7 mmHg, P \u3c 0.05). Despite an ~8 mmHg lower mean arterial blood pressure during both HG and KE exercise following salt restriction, neither central nor peripheral hemodynamics were altered. Therefore, salt restriction can lower blood pressure during exercise in subjects with hypertension, reducing the risk of cardiovascular events, without impacting central and peripheral hemodynamics during either arm or leg exercise

EFFICACY OF ALIROCUMAB IN 1,191 PATIENTS WITH A WIDE SPECTRUM OF MUTATIONS IN GENES CAUSATIVE FOR FAMILIAL HYPERCHOLESTEROLEMIA

Background Mutation(s) in genes involved in the low-density lipoprotein receptor (LDLR) pathway are typically the underlying cause of familial hypercholesterolemia. Objective The objective of the study was to examine the influence of genotype on treatment responses with alirocumab. Methods Patients from 6 trials (n = 1191, including 758 alirocumab-treated; Clinicaltrials.gov identifiers: NCT01266876; NCT01507831; NCT01623115; NCT01709500; NCT01617655; NCT01709513) were sequenced for mutations in LDLR , apolipoprotein B ( APOB ), proprotein convertase subtilisin/kexin type 9 ( PCSK9 ), LDLR adaptor protein 1, and signal-transducing adaptor protein 1 genes. New mutations were confirmed by Sanger sequencing. Results One or more specific gene mutations were found in 898 patients (75%): 387 and 437 patients had heterozygous LDLR defective and negative mutations, respectively; 46 had a heterozygous APOB -defective mutation; 8 patients had a heterozygous PCSK9 gain-of-function mutation; 293 (25%) had no identifiable mutation in the genes investigated. LDL cholesterol reductions at Week 24 were generally similar across genotypes: 48.3% (n = 131) and 54.3% (n = 89) in LDLR -defective heterozygotes with alirocumab 75 mg Q2W (with possible increase to 150 mg at Week 12) and 150 mg Q2W, respectively; 49.7% (n = 168) and 60.7% (n = 88) in LDLR -negative heterozygotes; 54.1% (n = 20) and 50.1% (n = 6) in APOB -defective heterozygotes; 60.5% (n = 5) and 94.0% (n = 1) in PCSK9 heterozygotes; and 44.9% (n = 85) and 55.4% (n = 69) in patients with no identified mutations. Overall rates of treatment-emergent adverse events were similar for alirocumab vs controls (placebo in 5 trials, ezetimibe control or atorvastatin calibrator arm in 1 trial), with only a higher rate of injection-site reactions with alirocumab. Conclusions In this large patient cohort, individuals with a wide spectrum of mutations in genes underlying familial hypercholesterolemia responded substantially and similarly to alirocumab treatment

Longitudinal and age trends of metabolic syndrome and its risk factors: The Family Heart Study

BACKGROUND: We report longitudinal changes in the metabolic syndrome (MetS) in 2,458 participants from 480 families in the Family Heart Study. Participants were examined between 1994–96 (FHS-T1) and 2002–03 (FHS-T2), about 7.4 years apart. Additionally, the impact of medication on estimates of MetS prevalence, and associations of MetS with prevalent coronary heart disease (CHD) and type 2 diabetes (T2D) were studied. METHODS: Three definitions for MetS prevalence were considered. One represented the original (o) National Cholesterol Education Program (NCEP) MetS criteria. Two others considered the confounding of medications effects, respectively (m) lipid medications constituted a categorical diagnostic criterion for lipids variables, and (c) lipids and blood pressure variables were corrected with average clinical trials medications effects. Logistic regression of MetS on CHD and T2D, as well as the trend analysis of MetS by age, were performed. RESULTS: MetS increased from 17.1% in FHS-T1(o) to 28.8% in FHS-T2(o); from 19.7% in FHS-T1(m) to 42.5% in FHS-T2(m); and from 18.4% in FHS-T1(c) to 33.6% in FHS-T2(c). While we observed adverse changes in all risk factors, the greatest increase was for waist circumference (25%). The percentages of MetS were about 2 to almost 3 times higher in ages 50 years and older than in younger ages. The odds of having prevalent CHD were about 2.5 times higher in the subjects classified with MetS than without. CONCLUSION: MetS percentages increased noticeably longitudinally and cross-sectionally with older age. These conclusions were reached with and without considering medication use, but correcting risk factors for medications use affects the MetS prevalence estimates. As found in other studies, MetS was associated with increased odds for prevalent CHD

High-fat meal effect on LDL, HDL, and VLDL particle size and number in the Genetics of Lipid-Lowering drugs and diet network (GOLDN): an interventional study

<p>Abstract</p> <p>Background</p> <p>Postprandial lipemia (PPL) is likely a risk factor for cardiovascular disease but these changes have not been well described and characterized in a large cohort. We assessed acute changes in the size and concentration of total and subclasses of LDL, HDL, and VLDL particles in response to a high-fat meal. Participants (n = 1048) from the Genetics of Lipid-Lowering Drugs and Diet Network (GOLDN) Study who ingested a high-fat meal were included in this analysis. Lipids were measured at 0 hr (fasting), 3.5 hr, and 6 hr after a standardized fat meal. Particle size distributions were determined using nuclear magnetic resonance spectroscopy. Analyses were stratified by baseline triglycerides (normal vs. elevated) and gender. The effect of PPL on changes in lipoprotein subclasses was assessed using repeated measures ANOVA.</p> <p>Results</p> <p>Postprandially, LDL-C, HDL-C, VLDL-C, and triglycerides increased regardless of baseline triglyceride status, with the largest increases in VLDL-C and TG; however, those with elevated triglycerides demonstrated larger magnitude of response. Total LDL particle number decreased over the 6-hour time interval, mostly from a decrease in the number of small LDL particles. Similarly, total VLDL particle number decreased due to reductions in medium and small VLDL particles. Large VLDL particles and chylomicrons demonstrated the largest increase in concentration. HDL particles demonstrated minimal overall changes in total particle number.</p> <p>Conclusions</p> <p>We have characterized the changes in LDL and VLDL particle number, and their subclass patterns following a high-fat meal.</p

Alirocumab efficacy in patients with double heterozygous, compound heterozygous, or homozygous familial hypercholesterolemia

Background Mutations in the genes for the low-density lipoprotein receptor ( LDLR ), apolipoprotein B, and proprotein convertase subtilisin/kexin type 9 have been reported to cause heterozygous and homozygous familial hypercholesterolemia (FH). Objective The objective is to examine the influence of double heterozygous, compound heterozygous, or homozygous mutations underlying FH on the efficacy of alirocumab. Methods Patients from 6 alirocumab trials with elevated low-density lipoprotein cholesterol (LDL-C) and FH diagnosis were sequenced for mutations in the LDLR , apolipoprotein B, proprotein convertase subtilisin/kexin type 9, LDLR adaptor protein 1 ( LDLRAP1 ), and signal-transducing adaptor protein 1 genes. The efficacy of alirocumab was examined in patients who had double heterozygous, compound heterozygous, or homozygous mutations. Results Of 1191 patients sequenced, 20 patients were double heterozygotes (n = 7), compound heterozygotes (n = 10), or homozygotes (n = 3). Mean baseline LDL-C levels were similar between patients treated with alirocumab (n = 11; 198 mg/dL) vs placebo (n = 9; 189 mg/dL). All patients treated with alirocumab 75/150 or 150 mg every 2 weeks had an LDL-C reduction of ≥15% at either week 12 or 24. At week 12, 1 patient had an increase of 7.1% in LDL-C, whereas in others, LDL-C was reduced by 21.7% to 63.9% (corresponding to 39–114 mg/dL absolute reduction from baseline). At week 24, LDL-C was reduced in all patients by 8.8% to 65.1% (10–165 mg/dL absolute reduction from baseline). Alirocumab was generally well tolerated in the 6 trials. Conclusion Clinically meaningful LDL-C–lowering activity was observed in patients receiving alirocumab who were double heterozygous, compound heterozygous, or homozygous for genes that are causative for FH